NOAA Facility Electrical and Grounding Survey February 26, 2021

Lee Santoro Electrical Engineer Summit Kinetics

Andrew Cooper Electrical Engineer Summit Kinetics 1 Abstract

At the request of the National Oceanic and Atmospheric Administration (NOAA) a survey of the electrical and grounding systems of the Mauna Loa Observatory (MLO) was undertaken. MLO is a premier atmospheric research facility that has been continuously monitoring and collecting data related to atmospheric change since the 1950's.

The electrical and grounding systems of the MLO facility have evolved over six decades of use, modified and expanded as the scientific needs of the facility have changed. The result is a patchwork of old and newer systems built to the prevailing standards of the era in which they were installed.

The report outlines the geological and resultant extreme electrical isolation from reasonably conductive soil and ground water at this site. The site’s extremely poor ground conductivity provides no practical remediation using a conventional approach for a properly earthed grounding electrode system. As a result, the conclusions and recommendations provided treat the site as a whole, similar to a ship, requiring extraordinary efforts to provide a safe and effective grounding system.

The high level results of this survey are contained in this report, along with recommendations for the improvement of these systems. The goal is to support the continued atmospheric and climate research that is proving ever more critical in this era of climate change.

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 2 Table of Contents

1 Abstract______2 2 NOAA Mauna Loa Site______6 2.1 Facility______7 2.1.1 Logistics______8 2.1.2 Safety______8 2.2 Landscape______8 2.3 Geology______9 3 Grounding and Bonding Theory______11 3.1 Typical Structural Grounding and Bonding______11 3.2 Soils and Substrates______12 3.3 Moisture and Conductivity______12 3.4 Testing______12 3.5 Conventional Remediation and Conductivity Enhancement______12 3.6 Ufer or Concrete Encased Electrode Grounding______13 4 Current Site Conditions and Challenges______14 4.1 Current Grounding System______14 4.2 Ground Measurements______15 4.3 MLO Site Power______16 4.4 Electrical Equipment______19 4.5 Facility Notes______21 4.5.1 NDACC Building______21 4.5.2 Keeling Building______21 4.5.3 Butler Building______22 4.5.4 Telcom Building______23 4.5.5 US Army LMR______23 4.5.6 AEC Building______24 4.5.7 The Simpson Building (Groundwinds)______24 4.5.8 High Sampling Tower______25 4.5.9 Mauna Loa Solar Observatory______25 4.5.10 ASIAA (AMiBA)______26 4.6 Site Communications______26 4.6.1 Telephone______27 4.6.2 Network______27 5 Recommendations______28 5.1 High Priority Recommendations______28 5.1.1 Removal of the 50kVA Single Phase Service______28

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 3 5.1.2 Removal the Special Projects Panel______29 5.1.3 Resolution of Code Issues______30 5.1.4 General Electrical System Condition______30 5.1.5 Inspection and Repair of the Existing Grounding System______31 5.2 Facility Improvements______31 5.2.1 Design and Installation of a Main Facility Primary Ground Point______31 5.2.2 Design and Installation of Ufer Ground / Utility Corridor System______32 5.2.3 Communications Standardization and Consolidation______33 5.3 Follow-On recommendations______34 5.3.1 Site Wide Electrical Utility Distribution Standardization______34 5.3.2 Future Construction Recommendations______34 5.3.3 Maintenance of the Existing Grounding System______34 5.3.4 Design and Upgrade of the On-Site Computer Network______35 5.3.5 Relocation of Radio Frequency Communications______35 5.3.6 Design of Photovoltaic Additions______35 6 References______37

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 4 Table of Figures Figure 1: NOAA Mauna Loa Facility as of late 2020______6 Figure 2: MLO Facility Location on the Island of Hawaii______7 Figure 3: MLO Site Looking Toward Sampling Tower with Typical Surface Conditions______9 Figure 4: Exposed Mauna Loa lava flows at Kealakekua Bay______10 Figure 5: Electrical Conductivity of Various Rocks______11 Figure 6: Typical Grounding Distribution Panel at the Butler Building______14 Figure 7: Performing Ground Quality Measurements______15 Figure 8: Power Line and Transformer Locations______17 Figure 9: Electrical and Communications Conduits beside the AEC Building______18 Figure 10: Unburied Conduit at the Camera Building______18 Figure 11: Power Line Termination and Transformers______19 Figure 12: Mauna Loa Observatory Facility Map______20 Figure 13: Circuit Breaker Panel Located Above a Sink in the Keeling Building______22 Figure 14: Distribution Panels and Meters on the Rear of the Butler Building______23 Figure 15: The Hawaii Telcom, Army, and AEC Buildings______24 Figure 16: The Simpson Building (Groundwinds) with the AEC Building (blue)______25 Figure 17: Mauna Loa Solar Observatory______26 Figure 18: Typical Communications Pull Box______27 Figure 19: 50kVA Transformer Enclosure______28 Figure 20: The Special Projects Panel______30 Figure 21: Conduit at the Base of the Special Projects Panel______31 Figure 22: Utility Corridor Cross Section______33 Figure 23: Aerial view of the MLO Facility______36

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 5 2 NOAA Mauna Loa Site

The Mauna Loa Atmospheric Baseline Observatory (MLO) operated by the National Oceanic and Atmospheric Administration (NOAA) is located on the north slope of the Mauna Loa Volcano at an elevation of 3,400m (11,150ft). The site is about 5.8 miles north and 770m (2,500ft) below the summit of Mauna Loa and the summit caldera, and about 2.5 km (1.5 miles) from the boundary of Hawaiʻi Volcanoes National Park.

Figure 1: NOAA Mauna Loa Facility as of late 2020

Latitude/Longitude: 19.5364N /155.5761W

The observatory is a premier atmospheric research facility that has been continuously monitoring and collecting data related to atmospheric change since the 1950's. In addition to NOAA facilites the site also hosts a range of experiments belonging to other governmental agencies and research institutions.

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 6 Figure 2: MLO Facility Location on the Island of Hawaii

2.1 Facility MLO is a campus composed of many small buildings and sheds housing atmospheric sampling instruments, walk-up scientific tower, and several communications antennae. Anchoring the science on the site are the two larger buildings. The Keeling Building constructed in 1956 is the oldest structure on the site. The NDACC Building, constructed in 1997 is currently the largest structure on-site. There are approximately sixteen smaller structures ranging from modest buildings to utility sheds scattered across the site. In addition to the structures there are numerous scientific installations and free standing instruments.

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 7 2.1.1 Logistics The site is accessed by a 17.6-mile single-lane paved road that branches off Saddle Road (State Route 200) and winds its way up the mountain. The road is characterized by numerous blind curves, hills, and dips as it climbs across recent lava flows to the site. It is an hour drive from Hilo or Kona. The road is open to the general public as far as a gate immediately below the facility. To the side of the gate is an unpaved parking lot and the trail head for a recreational trail that leads into the national park and the Mauna Loa summit caldera. 2.1.2 Safety The site is located at over 3,300m (11,000ft) elevation with a 32% reduction in air pressure with respect to sea level. Personnel must be aware of and plan for the effects of altitude. Electrical equipment must be generously de-rated to account for the reduction in cooling due to reduced atmospheric pressure. The high altitude also results in occasional severe weather conditions. Emergency services in the area are provided by the military fire department located at Pōhakuloa Training Area (PTA) with a response time of over half an hour needed to reach the NOAA site. Personnel working at the site should possess additional training in advanced first aid and the equipment necessary to be self sufficient in addressing safety incidents. 2.2 Landscape The site is a lava covered slope of approximately 15% grade sloping downwards to the north. The site is barren with no apparent plant or animal life. Biologically the site is classified as a high alpine desert with 10-20” of precipitation anually.

The site is primarily covered in basaltic 'a'ā lava with small patches of smoother pāhoehoe. ʻAʻā is characterized by a loose rubble called clinker at the surface with layers of solid basalt at the core of each successive flow. This results in a surface of loose, abrasive and irregular material a meter or more in depth with occasional exposures of solid substrate.

Much of the site was disturbed to create a lava diversion berm upslope of the observatory to protect the site from minor lava flows and/or provide enough time for observatory staff to escape an active lava flow.

Given the high elevation and exposure the site is subject to strong winds on a regular basis. Fog and light rain are common, particularly in the afternoon when tropical convection brings moisture to higher elevations. The site experiences snow and ice periodically, with freezing fog common in the winter, and heavy snow on occasion.

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 8 Figure 3: MLO Site Looking Toward Sampling Tower with Typical Surface Conditions

2.3 Geology Mauna Loa is a classic shield volcano in the shield building phase characterized by large fluid lava flows that cover extensive areas in periodic eruptions. At the MLO site this has resulted in a subsurface structure that consists of relatively thin layers of solid material 2-7 feet thick interspersed with broken clinker from the upper and lower margin of each flow 1-11 feet thick. The dense vesicular basalt is unweathered, hard, and moderately fractured. The loose clinker is sand to boulder sized, highly angular, sharp, abrasive, hard, and brittle.[MLO Geo 1994]

Mauna Loa consists of uniform tholeiitic basalts made up of fine grained to glassy material. This material is approximately 52% silicon dioxide, 12-14% aluminum oxide, 10% calcium oxide, 9-10% iron oxide, with a mixture of other metal oxides making up the balance. [Wright, 1971]

Hydrologic studies of the region indicate these fractured lava flows are highly porous, allowing precipitation to quickly percolate through. Combined with limited rainfall the resulting water tables lie at considerable depth from the surface. It is likely the nearest permanent water table is thousands of feet below the site. [Pierce & Thomas, 2009]

These geologically young lava flows at the surface are also quite clean with little clay, few salts or calcium minerals deposited in the matrix. The result is a base material under the NOAA site that is generally a very poor conductor.

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 9 The same features that make the MLO site so valuable to atmospheric science result in a very challenging grounding situation at this facility. A substrate of geologically young low conductivity volcanic rock, with little weathered or organic material, poor retention of moisture, low precipitation, and a distant water table all present a situation more difficult than nearly any other location one could find.

Figure 4: Exposed Mauna Loa lava flows at Kealakekua Bay

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 10 3 Grounding and Bonding Theory

The goal of any grounding and bonding system is to provide a low-impedance path for potentially hazardous currents. The proper functioning of grounding and bonding systems is critical for the safety of both personnel and equipment. 3.1 Typical Structural Grounding and Bonding Bonding provides a safe path for fault currents back to the source. This helps insure the correct functioning of safety devices such as circuit breakers and GFI devices. These currents are generally the result of some electrical fault, either equipment failure or damage to electrical distribution infrastructure.

Grounding allows for the safe dissipation of currents that originate outside the electrical system, usually lightning strikes on, or nearby the electrical distribution system. Grounding also prevents the electrical distribution system from “floating”, keeping it at a known voltage with respect to the surrounding structures and the earth itself.

Bonding is accomplished by connecting any metal elements of the electrical distribution system to the power distribution neutral at the main distribution point. This bonding point is then distributed via conductor, the “ground” conductor, throughout the distribution system. All electrical junction boxes, conduits, and the metal chassis or frames of all attached electrical appliances are attached to this ground conductor. Ideally there should be zero electrical current in this return path, the presence of significant current is indicative of a fault.

Most structures are grounded using one or more grounding rods installed near the electrical service and connected to the same distribution point as the bonding system to connect the electrical system with the local earth ground. This ground rod will electrically attach the system neutral to the earth, or ground.

Thus grounding and bonding is accomplished with the same conductors and is often simply referred to as grounding. Electrical standards such as the National Electric Safety Code make a clear distinction between these two concepts and understand is helpful in the design and maintenance of grounding and bonding systems. [NESC]

Figure 5: Electrical Conductivity of Various Rocks

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 11 3.2 Soils and Substrates The effectiveness of any grounding system depends largely on soil and rock surrounding the system and the ability of the ground to absorb and dissipate large electrical currents. In other words, the ground must have good conductivity to properly support the grounding system. The conductivity of the ground, or the ease with which it conducts electrical currents, varies with different substrates.

3.3 Moisture and Conductivity The conductivity is strongly influenced by moisture content and temperature as most substrates consist of poorly conductive bulk materials, conduction thus takes place through water and the various dissolved salts present in subsurface soils and rock. When moisture content is below 10 percent, it can decrease conductivity significantly. Temperatures below freezing also decrease conductivity. When moisture turns to ice, conductivity decreases sharply. In areas subject to freezing winters, installing the ground system below the frost line is standard for maintaining good conductivity.

3.4 Testing When considering the grounding conditions at any site, it is essential to test soil conductivity. Testing is performed using specialized ground test instruments. The procedure involves measuring between an electrode attached to the building ground and one or more stakes driven into the ground at a specified distance from the structure.

Test results must be examined carefully, since conductivity levels can vary widely, even in apparently similar soils. In general, black dirt, or soils with high organic content, are usually very good conductors because they tend to retain more moisture, leading to good conductivity. Rocky or sandy soils, which drain faster, tend to be less moist and are therefore lower conductivity. The solid rock and volcanic cinder substrates often encountered in Hawaii can have very low moisture content, and have such is a notably ineffective grounding substrate.

3.5 Conventional Remediation and Conductivity Enhancement Various techniques are available for improving the performance of grounding systems when poorly conductive conditions are encountered. In areas where soil conductivity is moderately low additional grounding rods may be installed, or lengths of grounding conductors may be buried around the structure.

250.56 Resistance of Rod, Pipe, and Plate Electrodes. A single electrode consisting of a rod, pipe, or plate that does not have a resistance to ground of 25 ohms or less shall be augmented by one additional electrode of any of the types specified by 250.52(A)(4) through (A)(8). Where multiple rod, pipe, or plate electrodes are installed to meet the requirements of this section, they shall not be less than 1.8 m (6 ft) apart. [NFPA 70]

Bentonite is a clay substance used for grounding systems in soils with low conductivity as it retains moisture. However, conduction in bentonite only occurs when ions move. Ionic conductivity can only occur in a solution, which means that bentonite must be wet to provide low-resistivity levels. When it loses moisture, its conductivity decreases and it contracts, losing contact with the surrounding soil.

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 12 Another way to improve conductivity is to treat the soil with a salts. This is the basis of commonly used chemical grounding rods. Combined with moisture, salts leach into the soil and improve conductivity. This method dramatically increases the conductive area of the grounding system to the entire surface of the treated substrate.

Chemical grounding rods are not without practical issues… As the salts are depleted, the soil reverts to its untreated condition and the system has to be recharged periodically. Also, the leachate may contaminate groundwater; local environmental regulations, may then rule out this alternative. Full removal of the grounding rods could require excavation of a considerable volume of material.

3.6 Ufer or Concrete Encased Electrode Grounding A practical solution to greatly increase the area of the ground electrode is to utilize the entire foundation of a structure. With an effectively large ground electrode even low conductivity substrates can provide effective grounding of the structure.

Known as Ufer electrodes, foundation earth electrodes, or concrete encased electrodes, this grounding method was developed during World War II by Herbert Ufer working as a consultant for the US Army. Ufer grounding can be installed in new construction as a method of supplementing the grounding electrode system.

250.52 Grounding Electrodes. (3) Concrete-Encased Electrode. An electrode encased by at least 50 mm (2 in.) of concrete, located horizontally near the bottom or vertically, and within that portion of a concrete foundation or footing that is in direct contact with the earth, consisting of at least 6.0 m (20 ft) of one or more bare or zinc galvanized or other electrically conductive coated steel reinforcing bars or rods of not less than 13 mm (1⁄2 in.) in diameter, or consisting of at least 6.0 m (20 ft) of bare copper conductor not smaller than 4 AWG. Reinforcing bars shall be permitted to be bonded together by the usual steel tie wires or other effective means. [NFPA 70]

Concrete-encased electrodes enhance the effectiveness of the grounding electrode system in two ways: the concrete absorbs and retains moisture from the surrounding soil, and the concrete provides a much larger surface area in direct contact with the surrounding soil. This is especially helpful at sites with high soil resistivity and/or limited area for installing a grounding electrode system.

Use of concrete-encased electrodes is accepted, and often recommended, by all major electrical standards. Specific requirements for a given site can be found in the applicable standards. [NFPA 70] [NESC] [IEC 62305-3] An excellent reference for these types of grounding systems as they apply to the Mauna Loa site can be found in Motorola Manual R56 concerning the design of remote communications sites. This manual addresses many of the same challenges found at MLO including mountaintop sites and towers. [Mot R56]

Ufer grounds can be easily constructed as part of the structure foundation and require no special expertise or equipment to install. If required the grounding may be removed entirely by breaking up and removing the concrete in which they are encased. As this is generally shallow no extensive excavation would be required.

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 13 4 Current Site Conditions and Challenges

The NOAA Mauna Loa site offers a number of challenges in constructing a safe electrical system and an effective grounding system. Located far from the island’s electrical infrastructure at the end of an exposed power line. Sited on recent lava flows the underlying rock is highly permeable with a low moisture content. The igneous rocks consist primarily of glassy or fine grained metal oxides that are very poor conductors.

4.1 Current Grounding System The existing ground system is assembled from a number of metal and chemical ground rods at each structure. These are interconnected via heavy ground cables run between a set of distribution panels located at key points throughout the complex. From these panels ground leads are tied to the various structures across the site.

The existing grounding has evolved into a layered system over the decades. While the was likely not accomplished by design it does offer some protection of the facility.

Much of the existing grounding system and distribution panels were installed during the 1991 electrical upgrade. The improvements were well designed and workmanship was generally good, as a result the system is still serviceable. The system shows some effect of the intervening four decades and needs some attention. Some of the exothermic bonds are in need of rework due to age and corrosion.

Figure 6: Typical Grounding Distribution Panel at the Butler Building

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 14 Several buildings are equipped with stand-alone grounding systems. Notably the NDACC building features a surrounding ring of chemical ground rods and a good internal grounding system. The effectiveness of the chemical grounding rods is likely variable dependent on recent precipitation.

4.2 Ground Measurements The instrument used was a EM480D digital earth ground resistance test set. This is an industrial ground test instrument used to verify the correct function of an electrical system ground. This is done by connecting the meter to the system ground point and two conductive stakes driven into the ground near the structure.

Correct function of this instrument was confirmed in measuring the effective ground connection of several nearby structures including the new county bathrooms at the Gilbert Kahele Recreation Area in the valley directly below the MLO facility. For the test cases the meter performed properly indicating permissible grounding.

Figure 7: Performing Ground Quality Measurements

The ground test meter returned no reasonable readings when attempting to measure grounding on multiple structures at the MLO facility. This includes those with chemical grounding rods, with attempts made to measure directly at the grounding rod terminal. The EM480D measures up to 2kΩ, indicating poor conductivity under the MLO facility as expected from the geology. Ground resistances of under 25ohms are specified by code with some form of augmentation required if above this value. [NFPA 70]

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 15 Attempts to improve the performance of the ground test meter including saturating the ground around the test stakes with water failed to return any reasonable readings.

In expectation that a standard building ground test instrument would fail to provide reliable data, measurements were made instead with a megaohm meter. This Hotlzer/Cabot megaohmeter allows reading up to 100’s of megaohms using an excitation voltage of 1kV.

In contrast to the ground test meter, this meter provided reasonably consistent data across the Mauna Loa site, confirming that while ground conductivity is low and variable, some conductivity is present and usable.

Table 1: Ground resistance measurements Location Probe Dist. Resistance (m) (kΩ) South side Atlas Dome 5 1200 Tower going north 5 1500 Tower going east 5 400 Open ground near diversion structure 5 3500 NW Corner ground buss 5 2000 Simpson Bldg. chemical ground rod 5 300 Average: 1480

• Ground resistance meter out of range for all measurements on site • Tried wet and dry ground rods at tower and Butler Building • Used both fixed site ground points as well as driven rod for testing • Ground rods separated by 5 meters typically as per manufacturer’s recommendation, this distance worked as expected in earlier test sites on-island areas but did not on MLO site

• Site measurements taken Nov 23, 2020 between noon and 3 PM, weather dry with no measurable precipitation in the preceding 24 hours In general ground measurements confirm what was suspected when considering the geology of the area. Poor subsurface conductivity was verified making traditional grounding systems ineffective. While chemical ground rods offer some improvement, large area grounding systems such as Ufer grounds are likely the best choice for use at the Mauna Loa facility.

4.3 MLO Site Power The power system for the MLO site is provided by the Hawaii Electric Light Company (HELCO), a subsidiary of the Hawaiian Electric Company (HECO). Power is delivered via a 12.47kV power line over 16 miles from the Kulani Substation. This power line is highly exposed on the side of Mauna Loa to inclement weather at high elevation.

The power line terminates in a set of transformers at the northwestern corner of the site. There are three separate transformers or transformer sets in use. A ground mounted 50kVA in a small chain link enclosure, a larger 300kVA pad mounted transformer, and a set of pole mounted 25kVA transformers on the last pole of the power line.

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 16 Figure 8: Power Line and Transformer Locations

The fenced enclosure housing the 50kVA transformer is the original power source for the facility. This has seen extensive modification over the decades and exhibits significant safety issues. See section 5.1.1 for details on these issues.

The 300kVA transformer supplies three phase power to the NDACC building, ASIAA (AMiBA), and through the distribution center in the Butler Building several other structures including the Keeling Building and Mauna Loa Solar Observatory. This is a modern transformer that appears to meet current code and is in good condition.

The final transformer on the line consists of a set of 25kVA pole mounted transformers supplying three phase power to the Army Building and the Simpson Building (Groundwinds). These appear serviceable and in acceptable condition.

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 17 Figure 9: Electrical and Communications Conduits beside the AEC Building

Figure 10: Unburied Conduit at the Camera Building

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 18 Figure 11: Power Line Termination and Transformers

The layered nature of the power system does present a number of troubling potential hazards. Significantly there are structures in close proximity that are provided power from separate transformers and distribution points. This creates the possibility of large voltage differences between adjacent structures in the case of equipment or bonding failure.

Much of the power distribution from the transformers to the various structures is in unburied or minimally buried conduit across the site. This is particularly true of the northeast cluster where multiple conduits lie in a confused tangle between the structures and the parking area.

4.4 Electrical Equipment With exceptions, the electrical equipment; distribution panels, circuit breakers, cables observed have seen long service life, but are generally in reasonably good shape and have been well maintained. The dry, cool nature of the site has aided in providing optimal conditions for electrical gear.

Most equipment noted is good quality equipment, primarily manufactured by Square-D, with no equipment noted that has a poor service record. Note, a number of older product lines, particularly circuit breaker panels from such as Zinsco, Sylvania, and Federal Pacific, have been known to have troubling service records, with immediate replacement recommended. None of these product lines were noted on site.

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 19 Figure 12: Mauna Loa Observatory Facility Map

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 20 4.5 Facility Notes Specific notes on some of the structures of the MLO facility are found below. Not all structures are listed, attention was given to key structures that support the site and the electrical and grounding systems

4.5.1 NDACC Building The NDACC building is the largest structure on-site, having been built in 1997 it is also one of the newest structures on-site. As expected of recent construction the electrical system is in excellent condition with no significant issues noted and meeting modern code. The grounding system of the NDACC building is based on a set of chemical grounding rods installed at the structure periphery tied to a set of grounding conductors within the structure. The NDACC Building hosts a photovoltaic array. The disconnect for this equipment is in the NDACC building electrical room. A surge suppressor is also present adjacent to the power distribution panels in the electrical room. 4.5.2 Keeling Building One of the oldest structures on the site built in 1956, the building and the adjacent sampling platform serves to house multiple instruments. Equipment performing the critical atmospheric gas measurements for which the NOAA Mauna Loa site is famous is located in this building. [Mims 2011] The structure has seen continuous modification and repair to serve several generations of scientific experiments. As a result the electrical system is disorganized and exhibits notable safety hazards and severe code violations. Immediate work should be undertaken to remediate these issues. While in need of work to rectify a number of issues here, the Keeling building also demands special care in any such work. Extensive coordination will be require to avoid disruption of the critical scientific efforts taking place in this area.

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 21 Figure 13: Circuit Breaker Panel Located Above a Sink in the Keeling Building

4.5.3 Butler Building The Butler Building is a prefab structure housing a workshop area and serving as a main distribution point for power to other facilities. Made by Butler Manufacturing of Kansas City, Missouri. This is one of two such structures on site, the other being the AEC building. While this is an older structure the building appears generally sound and in good repair. A set of electrical panels and meters are situated on the rear wall of the building serving multiple other structures including the Mauna Loa Solar Observatory, Keeling Building, the Dobson, Dome, and the AEC Building. The electrical distribution gear here is nearing end of life, repair and replacement parts will be increasingly difficult to replace. Recommend this switching center be considered for possible replacement in the near future. All of these feeds could be consolidated into the utility corridor proposed in section 5.2.2 of this report.

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 22 Figure 14: Distribution Panels and Meters on the Rear of the Butler Building

4.5.4 Hawaii Telcom Building Hawaii Telcom operates a small CMU block structure in the northeastern cluster providing data and communications to the facility. While the building is an older structure it appears completely serviceable with no notable safety issues.

The telecommunications building is served by a dedicated single phase drop with a meter and a disconnect located on the terminal pole of the HELCO powerline. This power feed is from the oldest utility power source on-site and needs to be re-fed( see section 5.1.1) or consolidated into the utility corridor proposed in section 5.2.2 of this report. 4.5.5 US Army LMR A communications shelter operated by the US Army is located in the northeastern cluster adjacent to the Hawaii Telecom building. This is a prefabricated building containing multiple Land Mobile Radio system receivers and transmitters that serve the US Army Pohakuloa Training Area in the saddle region directly below MLO. These radios are connected via conduit to a small communications tower located about 100’ down slope of the MLO facility. No notable issues or code violations were noted at this structure.. This power feed could eventually be consolidated into the utility corridor proposed in section 5.2.2 of this report. This structure represents the highest source of potential RF interference on site. Many of the “off-site” RF transmitters are located in this shelter.

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 23 4.5.6 AEC Building The Atomic Energy Comission Building is the other prefab structure by Butler Manufacturing. The building is one of the older structures on site dating from 1960’s and used to monitor fallout from nuclear tests in the Pacific Ocean. [HSB 1964] The structure shows its age, and while it the structure itself appears sound, substantial renovation should be undertaken before further significant use. This includes full upgrade of the electrical system to modern code. This power feed could eventually be consolidated into the utility corridor proposed in section 5.2.2 of this report.

Figure 15: The Hawaii Telcom, Army, and AEC Buildings

4.5.7 The Simpson Building (Groundwinds) The Simpson building is a relatively new structure in the northeastern cluster with a small Ash dome on the roof to accommodate a small telescope. Intended for atmospheric laser experiments it was never fully commissioned and now sits vacant. The structure is quite modern, well constructed, and complies with current electrical codes. A chemical ground rod is located at the north wall of the structure. A surge suppression unit is located adjacent to the circuit breaker panel.

Power is supplied by a dedicated feed and meter from the 25kVA 3 phase transformer set and meter on the terminal power pole. This facility is also one that should be consolidated into the utility corridor proposed in section 5.2.2 of this report. If funding prevents a complete utility corridor solution at this time, this structure could be used to temporally feed the electrical needs of the 50 KVA transformer recommended for demolition in section 5.1.1 of this report.

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 24 Figure 16: The Simpson Building (Groundwinds) with the AEC Building (blue)

4.5.8 High Sampling Tower A 120ft sampling tower tower is located at the far western end of the facility. As this tower is the highest structure on site it is highly exposed to possible lightning strike. As such particular care needs to be taken here. A ground distribution panel is located at the tower fence connecting the tower to the facility ground distribution network. A set of ground cables are evident at each corner of the tower, mechanically bonded to each vertical column and proceeding into the ground forming a radial ground. The bonding of these ground wires needs to be completely reworked if this tower is to remain on site. A number of instruments located on this tower are directly wired to several other structures, notably the Camera Building. Care should be taken to isolate any equipment that is directly wired in this manner as each cable is a potential path for lightning and lightning induced currents. Any equipment attached to such cables should be isolated from surrounding equipment and network communications. 4.5.9 Mauna Loa Solar Observatory The Mauna Loa Solar Observatory is operated by the National Center for Atmospheric Research. The telescopes and instruments are in a large structure located several hundred feet up slope from the main MLO facility. The facility is served by a partially buried power conduit run directly up from the Butler Building through a series of pull boxes. The power feed as well as communications

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 25 connections should be reworked and reinstalled. Power wiring within the building the power system appears to be well maintained and serviceable.

Figure 17: Mauna Loa Solar Observatory

4.5.10 ASIAA (AMiBA) AMiBA is one of the largest instruments on Mauna Loa, designed to investigate the cosmic microwave background radiation. As such is has larger power needs than most other experiments in the complex. This observatory sits at the far eastern end of the complex and is supplied power via a dedicated feed and meter from the 300kVA transformer. AMiBA is also one of the few facilities in the facility with substantial backup power, a diesel generator is co-located with the telescope. If properly sized a site wide solar based battery backup system may eliminate the need for a diesel-based power source on site. Power to this facility is routed in a trench and a series of pull boxes that follows the northern edge of the property. This trench should be marked and avoided during any excavation in this area. This installation is modern and appears to be in good shape and constructed to current code. 4.6 Site Communications Communication service is generally provided by Hawaiian Telecom, routed through a microwave link to the site from a relay station located on the lower slope of about 15 miles north.

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 26 4.6.1 Telephone The site is served by a POTS (plain old telephone service) line via the microwave feed that provides shared service to most of the structures. This is a high reliability connection available for emergency use. Cell signal is generally quite good across the site with both voice and data service available. The position of the facility provides clear line-of-site to at least two cell towers along Saddle Road in the valley below. This provides an excellent backup to the POTS line for emergency use. 4.6.2 Network Network connections between buildings are a variety of formats including CAT-3, CAT-5, or CAT-6 copper cabling with some fiber in places. Cabling appears to be of various quality. In several locations interior plenum rated network cable is run through exterior conduits. As often the case in layered infrastructure installed over time, network topology appears to have been installed piecemeal as needs changed resulting in a mishmash of overall organization and capacity. Network cabling needs to be standardized and consolidated, preferably in the utility corridor proposed in section 5.3.2 of this report, converted to fiber and standardized as detailed in 5.3.3 of this report.

Figure 18: Typical Communications Pull Box

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 27 5 Recommendations

After our site visit there are a number of specific recommendations to address the various issues present at MLO. These both address specific safety issues as well as issues of aging infrastructure. These recommendations have been developed with an eye to longevity as well as flexibility to address the ever changing needs of a research site.

These recommendations have been broken into a set of logical elements that may be accomplished as time and budget allows.

5.1 High Priority Recommendations The following high priority recommendations should be completed as soon as scheduling and budgets allow as they involve safety or risks to the facility.

5.1.1 Removal of the 50kVA Single Phase Service The 50kVA single phase transformer serving the Special Projects Panel and Hawaii Telcom represents a significant safety risk to the facility and staff. This consists of a pole type transformer mounted on a concrete slab at the far northwestern corner of the facility. This is surrounded by a chain link fence and supplied by a buried cable feed from a utility pole several hundred feet further northwest.

Figure 19: 50kVA Transformer Enclosure The safety hazards here are stark. The chain link enclosure offers far too little clearance from the exposed energized circuits, and does not meet the requirements of either OSHA 1926.966 or ANSI/IEEE C2-2017 which requires a clearance of 3.1m from energized

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 28 circuits of 12kV. [NESC] The buried supply cables for this transformer station are not in conduit, rather they are buried directly in rough volcanic clinker. The various components are aging and in visibly poor repair.

350 (B) Cables operating above 600V to ground shall have a continuous metallic shield, sheath, or concentric neutral that is effectively grounded. [NESC]

The long term solution to this issue is to install a new power feed tapped from the modern 300kVA pad mounted transformer to a new distribution point. The most likely location for this distribution point would be at the upslope edge of the NE cluster and at the edge of the paved parking area, though due to long term planning of the site currently underway, significant coordination will be needed to locate new electrical distribution equipment for maximum efficacy. At this time we propose this take the form of a small enclosing wall and standard wall mounted distribution cabinets. Sufficient capacity will be included for the existing experiments plus significant spare margin for future additions. The new power feed and distribution point will be designed and installed in parallel with the existing equipment without disruption of experiments. Once in place each affected facility will be migrated to the new distribution point one at a time with minimal disruption. This new distribution point will serve as a model for future work, sized with potential addition of similar distribution points elsewhere through the facility to provide power for guest experiments and integration into the UFER ground corridor concept (see below). Since the Ufer Corridor recommended in this report will likely be a long-term solution due to funding, we strongly recommend that the service be deemed at the earliest possible convenience. A temporary feed from the Groundwinds building will suffice. If coordinated well, this could end up being a representative design for the standardized electrical system mentioned in 5.4.1 of this report. 5.1.2 Removal the Special Projects Panel The Special Projects distribution panel was designed and installed as a temporary power solution with above ground armored conduit and a plywood enclosure. While designated as temporary the panel has served to supply power to multiple experiments since 1987. The plywood enclosure has visibly deteriorated and the equipment inside is well past end-of-life. This service and the safety issues represented must be resolved. See the solutions proposed in section 5.1.1 above.

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 29 Figure 20: The Special Projects Panel

5.1.3 Resolution of Code Issues Several notable safety hazards were observed during inspection of the electrical and ground systems that warrant timely attention. A licensed electrical contractor should be retained to resolve these issues. 5.1.4 General Electrical System Condition Much of the existing electrical system is aging and has seen a great deal of modification over the years. Greater attention should be given to electrical service infrastructure. In the absence of a licensed electrician on staff, retention of a local licensed electrical contractor should be considered to address numerous safety issues and to routinely inspect the various building electrical systems, perhaps on an annual basis. Existing electrical outlet circuits should be upgraded to GFCI and AFCI as required by current code. [NFPA 70]

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 30 Figure 21: Conduit at the Base of the Special Projects Panel

5.1.5 Inspection and Repair of the Existing Grounding System The existing grounding system is in general in good condition. There are several points where connections have suffered from age and corrosion, a number of other locations where the system does not meet current code. Ground bonds should be inspected and where necessary replaced or reworked. The existing chemical ground rods should be evaluated, and additional enhancement added as per manufacturer’s recommendations. 5.2 Facility Improvements The following recommendations represent a set of improvements that address the long term operation of the Mauna Loa facility.

5.2.1 Design and Installation of a Main Facility Primary Ground Point While the site is generally underlain by highly resistive dry substrate, there is one exception to this, the cesspool found at the northwest corner. The plume of moisture from this source will extend deep into the underlying rock and should allow a more conductive ground than is otherwise available on the site. By coincidence this location is also proximal to the entry point for utility power with distribution transformers and a ground panel nearby. We recommend that this fortuitous situation be used to create a primary ground point for the facility. Drilling of a borehole just down-slope of the moisture source and installation of a steel well casing into this shaft. This will then be connected to the facility ground system.

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 31 Such a ground would protect equipment and personnel from ground faults and lightning strikes within the facility. This would also provide protection from lightning strikes on the exposed power line leading across the mountainside to the site. 5.2.2 Design and Installation of Ufer Ground / Utility Corridor System We recommend that all key utilities be migrated to a corridor constructed throughout the site. This will consist of a chosen path for utility conduits with distribution nodes located along its length. These distribution nodes would be located at key points where each structure could be connected to the required utilities. This includes power, grounding, and communications. As trenching is extraordinarily difficult on the site, we propose a surface concrete structure that can be easily built to accommodate the required utility conduit. A concrete structure can also create an effective grounding system for the facility. Thus for the NOAA Mauna Loa site this utility and grounding corridor will be used to provide multiple solutions… An enhanced grounding system, a corridor for utility distribution, and safe walkways throughout the facility to replace the existing wooden walkways. The corridor taking the form of what is essentially a concrete sidewalk with an integrated utility trench. This open trench would be covered with standard deck gratings providing safe transit in inclement weather. The gratings can be simply removed to allow maintenance, replacement, or installation of new utilities. The corridor would incorporate a Ufer ground as described in section 3.6 above. Ground electrodes would be encased into the concrete creating a very large area Ufer ground. Provisions for connecting existing ground systems shall be made in order to tie into the nearest point in the utility corridor. The layout shall create a ground ring around the key sections of the facility. Existence of a ground ring will provide enhanced protection to lightning strike and provide a reliable path for an induced fault current. The existence of a conduit trench would avoids the necessity to perform extensive and difficult trenching for future projects and allow removal of the numerous above ground or poorly buried utility conduits currently found across the Mauna Loa site. Accommodating both power and communications cabling the corridor will form the backbone of the site infrastructure. Power distribution units will be located along this trench at key points to allow connection of existing structures and to accommodate future experiments. As the corridor would not involve any structures, demolition or construction of new structures could take place without disruption to other experiments. The layout of the Ufer corridor will be dictated by the existing site geometry, but it does appear that sensible solutions exist when considering possible routes through the facility. The corridor itself may serve as the anchor point for minor experiments. Small instruments could be mounted to the railings, likely near a distribution point within easy reach of power and communications.

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 32 Figure 22: Utility Corridor Cross Section

The corridor is also relatively easy to remove in the event of decommissioning the Mauna Loa facility is necessary. It is entirely a shallow surface installation not involving trenching or impact to ground water. The Ufer ground does not involve chemical electrodes or soil additions to improve conductivity. The corridor would be extremely low maintenance. The utility corridor will address many longstanding code and safety issues throughout the facility. Decommissioning and removal of problematic equipment becomes relatively easy. Addition of new equipment would be straightforward and not involve concessions to either safety of the integrity of other experiments. 5.2.3 Communications Standardization and Consolidation It is highly recommended that copper inter-building communications cabling be removed or migrated to fiber whenever practical. This particularly includes the CAT-5 Ethernet cabling currently used for inter-building network runs. Due to the grounding challenges discussed in this report large voltage differentials between structures may be the result of electrical distribution equipment failure, ground faults, or lightning induced surges. Such differentials may appear on low voltage communications cabling and present a risk to both equipment and personnel. Converting to fiber whenever possible eliminates this risk. Modern fiber network equipment is readily available at reasonable cost. Future installations will be advised to consider using only fiber and power in any inter-structure connections. A standard fiber

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 33 type and fiber connector shall also be chosen and recommended for any future installations. The networking manufacturers have standardized with LC duplex connectors and multi- mode fiber for the SFP and the latest SFP+ fiber transceiver modules that are supported by all major brands of network switches. This includes both the large enterprise rack mount and smaller industrial switches suitable for cabinet mounts and wide operational temperature ranges. Currently this is the obvious choice for fiber network equipment and is likely to remain so for a reasonable timeframe. While immediate removal and conversion of communications infrastructure may be cost and time prohibitive, this recommendation can be implemented gradually as time permits and facilities upgrade or new facilities are installed. 5.3 Follow-On recommendations The following recommendations are long term recommendations that capitalize on some of the improvements in previous sections.

5.3.1 Site Wide Electrical Utility Distribution Standardization Completion of the utility corridor will provide modular and standard connection points for any future installations or tenant facilities, for both power and network communications. These standards would be provided to any prospective tenant organization. This will avoid any misunderstandings on provided utilities, where these utilities are located, what cables or hardware is needed to make connections, and what capacities are available.

Since no structures are involved, maintenance or troubleshooting of utility issues would usually not involve entry into and possible disruption of other experiments. 5.3.2 Future Construction Recommendations A set of specifications should be developed for any future construction. These specifications should be supplied to architects or potential tenant organizations considering use of the MLO site. This standards should include the use of Ufer grounding, connection to the existing grounding network, and incorporation of the power and network standards recommended in sections 5.2.2 and 5.2.3. 5.3.3 Maintenance of the Existing Grounding System Grounding systems are all too often forgotten and ignored after installation. Given the critical nature of grounding in this facility to both safety and the sensitive nature of the various equipment deployed here this should be addressed. Staff training and procedures ought to be put in place to understand and inspect the grounding system. This need not be expensive nor time consuming. A single document concerning the grounding system shall be produced and made available for reference by on-site maintenance personnel that allows quick understanding of the grounding system. It shall include an annual or semi-annual inspection of the system performed and documented to observe the condition of key connection points and conductors. This inspection could be accomplished with minimal disruption and should require less than one day of effort. Several of the facilities, notably the NDACC building and the Simpson Building have chemical grounding rods installed. These may require periodic inspection and possibly

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 34 recharging to maintain performance. Refer to the manufacturer’s documentation for information on these components. 5.3.4 Design and Upgrade of the On-Site Computer Network Work on power distribution is also an opportunity to reorganize other utilities on-site. Any work should include a plan to re-structure the computer network. New junctions, conduit, switches, and fiber links can easily be included as part of the utility corridor concept. The goal would be to provide a network backbone independent of any structures. This would allow construction of new facilities and the demolition of outdated structures to proceed without interfering with ongoing science. Relocation of the computer network into the utility corridor would allow upgrade and maintenance of the computer network without entry into, or disruption of the various scientific experiments on-site. 5.3.5 Relocation of Radio Frequency Communications There are several radio frequency transmitter systems located at the site. They represent possible interference and disruption to sensitive scientific measurements. Relocation of the “off-site” RF sources to a single location is recommended. This will avoid interference with equipment across the site. We recommend moving all “offsite” RF sources, so they are located in the same area, as far away from the rest of the site structures as possible. Other than locating them to another area on the mountaintop, the best location for this is the northwest corner of the facility. Any work on power distribution and grounding should provide infrastructure for such relocation by providing a utility connection point for these services. In coordination with Hawaii Telcom and the US Army site standards will need to be developed to handle RF communications going forward. US Army requirements for communications infrastructure are available in the MIL standards series. [MIL-UFC-3-580- 01], [MIL-I3A], [MIL-HDBK-419A], etc. As recommended, a comprehensive plan for computer networking (see 5.3.4) with improved connectivity will reduce the need for ad-hoc network communications using WiFi access points. 5.3.6 Design of Photovoltaic Additions Although the scope of this report does not cover photovoltaic generation, no discussion of the electrical grounding system can avoid the subject. A desire for additional photovoltaic generating capacity, over and above the current deployment, has been discussed and is part of the long-term plan. Given the length and isolation of the transmission line providing the site electrical utility service we highly recommend completely converting the site to inverter-based power. There are many advantages to the quality and reliability of the site power which would be gained. The utility corridor recommended in section 5.3.2 would facilitate any such planning by providing connection points to support any solar additions. Design of the utility corridor should include identification of potential sites for photovoltaic and connection points. Further discussion and follow-on design work is recommended.

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 35 Figure 23: Aerial view of the MLO Facility

NOAA Mauna Loa Facility Electrical and Grounding Survey Page 36 6 References

Refer to the following sources for more material and background.

HSB 1964: Station on Mauna Loa To Be Built by A.E.C., Honolulu Star-Bulletin, Sep 26, 1964 IEC 62305-3: IEC 62305-3:2010 Protection against lightning - Part 3: Physical damage to structures and life hazard, International Electrotechnical Commission, 2010 MIL-HDBK-419A: MIL-HDBK-419A Grounding, Bonding, And Shielding For Electronic Equipments And Facilities, Naval Facilities Engineering Command, 1987 MIL-I3A: I3A Technical Criteria for the Installation Information Infrastructure Architecture, United States Army Information Systems Engineering Command, 2010 MIL-UFC-3-580-01: UFC 3-580-01 Telecommunications Interior Infrastructure Planning And Design, US Department of Defence, 2016 Mims 2011: Mims, Forrest M. Hawai‘i’s Mauna Loa Observatory: Fifty Years of Monitoring the Atmosphere, University of Hawaii Press, 2011 MLO Geo 1994: Geotechnical Engineering Exploration for Proposed NOAA Observatory Mauna Loa Hawaii, Pacific Geotechnical Engineers, Inc., 1994 Mot R56: R56 Standards and Guidelines for Communication Sites, Motorola Inc., 2005 NESC: IEEE C2-2017 National Electrical Safety Code, IEEE Standards Association, 2017 NFPA 70: NFPA 70 National Electrical Code, National Fire Protection Association, 2020 Pierce & Thomas, 2009: Pierce, Herbert A. and Thomas, Donald M. Magnetotelluric and Audiomagnetotelluric Groundwater Survey Along the Humuʻula Portion of Saddle Road Near and Around Puhakuloa Training Area, Hawaii, United States Geologic Survey, 2009 Wright, 1971: Wright, Thomas L. Chemistry of Kilauea and Mauna Loa Lava in Space and Time, United States Geological Survey, 1971 FAA-STD-019e: FAA-STD-019e Lightning and Surge Protection, Grounding, Bonding and Shielding Requirements for Facilities and Electronic Equipment, Federal Aviation Administration, 2005

IEEE 142:2007: IEEE 142-2007 - IEEE Recommended Practice for Grounding of Industrial and Commercial Power Systems (Green Book), IEEE Standards Association, 2007

UL 467: UL 467 Grounding and Bonding Equipment, Underwriters Laboratories, 2013

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