Eaton’s guide to surge suppression Applications notes Contents Description Page Summary of applicable ULா and IEEE standards for surge protection devices ........................................................ 4 High-resistance grounding and wye or delta surge protection devices .............................................................. 9 Surge current per phase (industry definition) .................................. 10 Facility-wide surge suppression ...................................................... 10 Debunking the surge current myth, “Why excessive surge current ratings are not required” ............ 11 Surge arrestor vs. surge suppressor ............................................... 12 Benefits of hybrid filtering in surge protection devices .................. 14 Factory automation (PLCs) and their need for surge suppression ........................................................................ 16 Surge protection devices with replaceable modules ...................... 17 Why silicon avalanche diodes are not recommended for AC powerline suppressors ..................................................... 18 Surge protective device frequently asked questions ...................... 20 2 EATON CORPORATION Eaton’s guide to surge suppression Why Eaton? provide protection for all For information on connected electronic loads. Eaton’s Powerware SPD As a premier diversified This design provides superior product line, please visit industrial manufacturer, Eaton suppression ratings and elimi- www.powerware.com/tvss. Corporation meets your electri- nates poor performance that cal challenges with advanced result from poor cable electrical control and power Innovative Technology connections and long lead distribution products, industrial lengths. Integrated transient Since 1980, Innovative automation, world-class manu- voltage surge suppression Technology products have facturing, and global engineering (TVSS) is the number one choice solved the most difficult elec- services and support. for surge suppression in new- trical transient problems for Customer-driven solutions come construction applications. business, industry, government in the form of industry-preferred and defense sectors. Innovative product brands such as Cutler- In addition to the extensive Technology products and Hammerா, MEMா, Holecா, integrated SPD offering, the Technologies protect electrical, Powerwareா and Innovative Cutler-Hammer SPD product data, telecom circuits, and Technologyா. line includes a wide variety of electronic equipment from the Eaton has an extensive fam- surge current ratings, monitoring effects of lightning-induced ily of surge protective devices features and external enclosure voltages, external switching (SPD) for any facility or applica- options. The Cutler-Hammer transients, and internally gener- tion. Using our Cutler-Hammer, SPDs are available from autho- ated electrical transients. rized Cutler-Hammer electrical Powerware and Innovative As a part of Eaton’s electrical Technology branded products wholesalers. For information on Eaton’s Cutler-Hammer SPD business since 2003, Innovative will ensure that the quality of Technology SPD products are power required to maximize product line, please visit www.eaton.com/tvss. even better positioned to deliver productivity in today’s competi- state-of-the-art customer solu- tive environment will be tions. Innovative Technology supplied in the most reliable, Powerware products are designed to be the safe and cost-effective manner. Lightning and other transient most rugged and durable SPDs Eaton has developed specific voltage and current-producing in the market. Based on exten- surge protection solutions for phenomena are harmful to sive proven field performance, commercial, industrial, insti- most UPS equipment and Innovative Technology was tutional, telecommunication, electronic load equipment the first to offer a 20-year full military, medical and residential connected to the UPS. For replacement warranty. Electrical applications—both for North example, the transient may engineers around the world America and throughout reach the critical load via an recognize Innovative Technology the world. unwanted activation of an as a leader in the SPD industry. unprotected static-switch A leading research company in a survey of over 10,000 users Cutler-Hammer bypass path around a UPS. Therefore, it is recommended rated Innovative Technology Eaton’s Cutler-Hammer SPDs practice that both the input number one in both product are designed to be fully inte- circuit to the UPS and the quality and service. grated into new switchgear associated UPS bypass cir- Innovative Technology SPD and new panels for the closest cuits (including the manual products are available in a wide possible electrical connection. maintenance bypass circuit) range of voltages (including volt- When installing a surge suppres- be equipped with effective ages up to 5 kV), surge current sor, it is important to mount it as Category “B” surge protective ratings, monitoring features and close to the electrical equipment device, as specified in IEEE Std. enclosure options. as possible in order to keep the C62.41-1991. Low-inductance wiring (lead length) between connections should be For information on Eaton’s the electrical equipment and the employed for this protection.ቢ Innovative Technology products, suppressor as short as possible. please visit www.itvss.com. As such, Eaton was the first Eaton's Powerware surge to introduce the Direct-Onீ protective devices can be fully bus bar connected SPD that integrated into power distri- provides customers with the bution units (PDUs), and are lowest system let-through designed to meet the voltage at the bus bar when demanding needs of the same compared to traditional cable mission-critical applications and connected surge protectors. By facilities that utilize Powerware utilizing a direct bus bar con- uninterruptible power systems nection, Cutler-Hammer SPDs (UPS). Powerware surge protec- achieve the industry’s lowest tion devices are available in a let-through voltage to effectively wide variety of surge current suppress both high and low ratings, monitoring features and energy transient events and enclosure options. ቢ Source: IEEE RDP Std. 1100-1999. EATON CORPORATION Eaton’s guide to surge suppression 3 Summary of applicable UL and IEEE standards for surge protection devices TABLE 1. STANDARD DESCRIPTIONS Standard (Current revision date) Purpose of standard/comments UL 1449 (1987)— 1. Safety test (constructed of approved components in a safe manner). Transient voltage surge suppressors 2. Suppressed voltage rating (let-through voltage using the IEEE C62.41 C1 test wave). (TVSS) Other IEEE recommended waveforms such as the C3 and B3 Ringwave are not tested by UL. ቢ UL 1449 (2nd Edition 1996) 1. Additional safety tests. Test for other standards used to improve safety of products. 2. Surge test. Let-through voltage tested at lower current than 1st Edition. 10 kA (IEEE Cat. C3) used for the first time; however, it was used only to see if products fail safely. UL 1449 (2nd Edition 2007) 1. Stringent new safety requirements. New tests subject TVSS units to prolonged AC overvoltage conditions to ensure safe failure modes 2. UL label changes to the wording of the short circuit current rating. 3. New Testing at 10, 100, 500 and 1000A and system voltage were added to ensure the units fail in a safe manner. UL 1449 (3rd Edition 2009) 1. TVSS will now be referred to as SPD (surge protective devices). 2. UL 1449 is now ANSI/UL 1449. 3. Addition of four types of SPDs to cover surge arrestors, TVSS, surge strips and component SPDs. UL 1283 (1996)— This safety standard covers EMI filters connected to 600V or lower circuits. The UL 1283 is a safety stan- Electromagnetic interference filters dard and does not include performance tests such as MIL-STD-220A insertion loss or Cat. B3 Ringwave let-through voltage tests. UL 497, 497A, 497B Safety standard for primary telephone line protectors, isolated signal loops and surge protection used on communication/data lines. No performance tests conducted for data/communication lines. IEEE C62.41.1 (2002) IEEE Guide on the Surge Environment in Low-Voltage AC Power Circuits. This is a guide describing the surge voltage, surge current, and temporary overvoltages (TOV) environment in low-voltage [up to 1000V root mean square (Rms)] AC power circuits. IEEE C62.41.2 (2002) IEEE-recommended practice on characterization of surges in low-voltage AC power circuits. This document defines the test waves for SPDs. IEEE C62.45 (2002) Guide on surge testing for low voltage equipment (ANSI). This document describes the test methodology for testing SPDs. IEEE Emerald Book Reference manual for the operation of electronic loads (includes grounding, power requirements, and so on). NEMAT LS-1 NEMA Technical Committee guide for the specification of surge protection devices including physical and operating parameters. NECT National Electrical Code Articles 245, 680 and 800. NFPAT 780 Lightning protection code recommendations for the use of surge protection devices at a facility service entrance. ᕃ UL 1449 does not require a maximum surge current test. Underwriter laboratories— electrical distribution system Notes UL 1449 (Revision 7-2-87), (i.e., UL 1449 does not include UL 1449 Second Edition does “Transient voltage surge the effects of installation lead not test a suppressor to other suppressors (TVSS)” length and overcurrent protec- important test waveforms such tion). A duty cycle