GENERAL INFO 170 (A) (A) Maintenance and Tests 700.3. Equipment, for the requirements covering automatic load control relays. Power and Lighting Emergency 924, ANSI/UL See Note: Informational restored. been has supply normal the senses device the when status normal to equipment lighting emergency the return supply by bypassing the dimming/switching controls, and to normal the of aloss of event the in levels illumination power full to dimmed lighting switched or emergency equipment normally-off normally set to used Adevice Control. Load automatic Relay lifeserious safety or health hazards, and similar functions. produce would interruption current where processes industrial systems, communications safety public pumps, fire elevators, systems, alarm and detection fire life, maintain to essential where ventilation as functions such for power provide also may systems Emergency institutions. similar and facilities, care health arenas, sports, theatres, hotels, as such persons, of numbers large by occupancy to subject buildings in control panic for and exiting safe for required is illumination artificial where assembly of places in installed generally are systems Emergency Note: Informational life. human to safety for essential illumination and power control and distribute, supply, to intended asystem of elements to accident of event the in or supply normal the of failure of event the in equipment and areas designated to both, or power illumination, supply automatically to governmental agency having These jurisdiction. systems are intended any by or codes, other or federal state, municipal, by emergency as Emergency Systems. Definitions 700.2. 5): No. (FPN 3): No. (FPN 1): No. (FPN interrupted. is system or supply electrical normal the when facilities required to both, or power, or illumination for electricity control and consisting of circuits and equipment intended to supply, distribute, systems emergency of maintenance and operation, installation, the of safety electrical the to apply article this of provisions The Scope 700.1. I. General SYSTEMS –EMERGENCY 700 ARTICLE (B) 4): No. (FPN 2): No. (FPN National Code Electrical — the systems are maintained in proper operating condition. ensure to jurisdiction having authority the to acceptable schedule T   upon installation and afterward. periodically system complete the of atest witness or conduct shall C ested Periodically. The authority having Test. jurisdiction Witness or onduct emergency systems in health care facilities, see Article 517. Article see facilities, care health in systems emergency F  see Standard for Health Care Facilities, NFPA 99-2012. NFPA Facilities, Care Health for Standard see facilities, care health in systems emergency of maintenance F safety or health hazards, and similar functions. life serious produce would interruption current where communications systems, industrial processes alarm systems, elevators, firepumps, public safety and detection fire life, maintain to essential where ventilation as functions such for power provide also may systems Emergency institutions. similar and facilities, care health arenas, sports theaters, hotels, as such persons, of numbers large by occupancy to subject buildings in control panic for and exiting safe illuminationassembly where artificial is required for E Emergency and Standby Power Systems, NFPA 110-1999. NFPA Systems, Power Standby and Emergency for Standard see systems, power standby and emergency F  see Life Safety Code, NFPA 101-2012. NFPA Code, Safety Life see safety, life to essential considered is lighting  F or further information regarding and wiring installation of or information further regarding performance and mergency systems are generally installed in places of of places in installed generally are systems mergency or further information regarding performance of of performance regarding information further or or specification of locations where emergency emergency where locations of specification or Those systems legally required and classed classed and required legally systems Those Systems shall be tested periodically on a on periodically tested be shall Systems EMERGI-LITE ACCESSORIES INFORMATION & GENERAL (A) 700.4. Capacity Systems. Power Standby and Emergency for Standard 2013, 110- NFPA see (EPSSs), systems supply power emergency of maintenance and testing on information For Note: Informational (C) (B) (A) 700.5. Transfer Equipment repair. or maintenance major for service of out is generator emergency the whenever available be shall source alternate temporary or Aportable met. are 700.3 Section of conditions other all provided 700.3(B), Section of requirement test the satisfying for permitted be shall operation shaving load Peak (B) (E) (D) Maintenance. Systems attery (C) (D) (C) (B) (A) Signals. 700-6. Use. (D)  for the following purposes described in 700.6(A) through (D). A udible and visual signal devices shall be provided, where practicable, Carrying Load. Carrying

Derangement.

anticipated load conditions shall be provided. be shall conditions load anticipated lighting and power systems maximum during T are used, inadvertent parallel operation shall be avoided. be shall operation parallel inadvertent used, are isolate the transfer equipment. Where bypass isolation switches  met. are conditions above the provided shaving, load peak for used be to permitted be shall source power alternate The priority. of order that in circuits, standby optional the (3) and circuits; standby required legally the (2) circuits; emergency the (1) to power adequate ensure to needed as provided is shedding load and pickup load selective automatic where or capacity adequate has source the where loads system standby optional and standby, required legally emergency, supply to permitted be shall source power alternate The S B having jurisdiction shallhaving jurisdiction require maintenance. periodic authority the engines, auxiliary in ignition or control, starting, unit equipment are involved, including batteries used for B charger is not functioning.  N use. system emergency for listed be shall below, VAC and 1000 rated switches, transfer Automatic held. mechanically A  C the normal source shall meet the requirements of article 705. article of requirements the meet shall source normal the systemsproduction installed to permit operation in parallel with power electric and equipment Transfer equipment. transfer the of operation any in supply of sources emergency and normal of interconnection inadvertent the prevent to installed and designed be shall equipment Transfer jurisdiction. having authority the by approved and use emergency for identified and automatic be shall General. availablethe maximum fault current at its terminals. for suitable be shall equipment system emergency The simultaneously. operated be to loads all for rating and capacity  ground fault shall be located at or near the sensor location. sensor the near or at located be shall fault ground indicated of event in taken be to action of course the on Instructions amperes. 1200 of current aground-fault for be shall devices signal the of setting maximum the and source, emergency the for means disconnecting system main of, the ahead or at, located be shall devices signal ground-fault the for sensor The more. or amperes 1000 rated devices protective circuit and ground to volts 150 than more of systems emergency  maintenance. and tests such of kept W G Means for testing all emergency emergency all testing for Means Load. Under esting Shaving. Load Peak and Shedding, Load Pickup, Load elective ypass Isolation Switches. utomatic transfer switches apacity and Rating. ot Functioning. round Fault. round A written record shall be be shall record Awritten Record. ritten Transfer equipment shall supply only emergency loads. emergency only supply shall equipment Transfer Transfer equipment, including automatic transfer switches, To indicate a ground fault in solidly grounded wye wye grounded solidly in fault aground To indicate To indicate derangement of the source. emergency To indicate that the battery is carrying load. carrying is battery the that To indicate To indicate that the battery battery the that To indicate An emergency system shall have adequate adequate have shall system emergency An Means shall be permitted to bypass and and bypass to permitted be shall Means shall be electrically operated and and operated electrically be shall Where battery systems or or systems battery Where GENERAL INFO 171 Emergency wiring Emergency . Current supply shall be such that, in Equipment for feeder circuits (including (including circuits feeder for Equipment Control conductors installed installed conductors Control shall meet one of the following conditions: following the of one meet shall Emergency systems shall meet the iring Design and Location. and Design iring enerator Control Wiring. Control enerator e protected by a listed fire-rated assembly that has a minimum e protected by a listed thermal barrier system for electrical e listed electrical circuit protective system with a minimum e installed in spaces or areas that are fully protected by eeder-Circuit Equipment. eeder-Circuit Fire Fire Protection. (D) through (D)(1) requirements additional following (3) in assembly occupancies fornot less than 1000 persons or in buildings above 23 m (75 ft) in height.  W circuits shall be designed and located to minimize the hazards that might cause failure dueto flooding, fire, conditions. adverse other and vandalism, icing, B emergency wiring only circuits contains and hours 2 of rating fire  system components with a minimum 2-hour fire rating.  G between the transfer equipment and the emergency generator shall be kept entirely independent of all other wiring and shall meet the conditions of 700.10(D)(1) B  for information guide UL note: Informational rating. fire 2-hour electrical circuit protective systems (FHIT) contains information rating fire the maintain to requirements installation proper on  transfer switches, transformers, panel boards) shall be either located in spaces fully protected by approved automatic fire suppression systems ( including sprinklers and carbon dioxide systems) or in spaces with a 2-hour fire resistance rating. F B  an approved automatic fire suppression system. B

Be encased inminimum a of 50 mm (2 in) of concrete

Feeder-circuit wiring Feeder-circuit (2) (3) (4) (5) (2) (3) III. Sources of Power Requirements General 700.12. the event of failure of the normal supply to, or within, the building emergency emergency lighting, concerned, buildings of group or power, or both will be available within the time required for the application but not to exceed 10 seconds. The supply system for emergency purposes, in addition to the normal services to the section, this of requirements general the meeting and building shall be one or more of the types of systems described in 700.12(A) through (D) below. Unit equipment in accordance with Section 700.12(E) shall satisfy the applicable requirements of this article. In selecting an emergency source of power, consideration shall be given to the occupancy and the type of service to be rendered, whether as duration, of longer or theater, a of evacuation for as duration, minimum for supplying emergency power and lighting due to an indefinite period of current failure from trouble either inside or outside the building. Equipment shall be designed and located to minimize the hazards that might cause complete failure due to flooding, fires, icing, and vandalism. Equipment for sources of power as described in Sections 700.12(A) through (E) where located within assembly occupancies for greater than 1000 persons or in buildings above 23 m (75 ft) in height with any of the following occupancy classes: assembly, and business, correctional, and detention residential, educational, mercantile, shall be installed either in spaces fully protected by approved automatic fire suppression systems (sprinklers, carbon dioxide systems, and so forth), or in spaces with 1-hour a fire rating. Informational note No. 1: For definition of Occupancy Classification, see Section 6.1of NFPA 101-2012, Life Safety Code. (C) Informational Note: For the definition of Occupancy Classification, see Section 6.1 of NFPA 101-2009, Life Safety Code (1) (1) (D) NATIONAL ELECTRICAL CODE ELECTRICAL NATIONAL A sign shall beplaced at the All boxes and enclosures (including transfer transfer (including enclosures and boxes All . Where removal of a grounding or bonding Wiring of two or more emergency circuits supplied iring from an emergency source to supply emergency and other iring within a common junction box attached to iring from two sources in a listed load control relay iring from the normal power source located he common bus of separate sections of the switchgear, switchgear, the sections of separate of bus common he eparate vertical switchgear sections or separate vertical egally required and optional standby circuits shall loads in accordance with 700.10(B)(5)a, b, c,and d as follows: W  unit equipment, containing only the branch circuit circuit branch the only containing equipment, unit emergency the and equipment unit the supplying circuit supplied by the unit equipment. W  supplying exit or emergency luminaires, or in a common emergency luminaires or exit to attached box, junction W  W enclosures. equipment transfer in t shall be permissible to utilize single or multiple feeders

Wiring supplied from two sources in exit or emergency luminaires or exit in sources two from Wiring supplied

to supply distribution equipment between an emergency source and the point where the combination of emergency, separated. are loads optional or required, legally  I  individual the or switchboard, the sections of separate enclosures shall be permitted to be supplied by single or multiple feeders without overcurrent protection at the source. T  switchboard sections, with or without a common bus, or or bus, common a without or with sections, switchboard shall enclosures separate in individual mounted disconnects be used to separate emergency loads from all other loads. S  not originate from the same vertical switchboard section, panel board enclosure, or individual emergency circuits. as enclosure disconnect L

mergency Sources. mergency . . 1) Identification. switches, generators, and power panels) for emergency circuits shall be permanently marked so they will be readily identified as component a of an emergency circuit or system. service entrance equipment indicating type and type and indicating equipment service entrance location of on-site emergency power sources. E  (2) (3) (4) (5) a b. d. c ( Grounding connection in the normal power source equipement interrupts the grounding electrode conductor connection to the alternate power source(s) grounded conductor, a warning sign shall be installed at the normal power source equipment stating: Wiring. from the same source shall be permitted in the same raceway, cable, box, or cabinet. Wiring from an emergency source distribution overcurrent protection to emergency loads shall equipment, wiring and other all of independent entirely kept be unless otherwise permitted in 700.10(B) (1) through (5):   Exception to (5)b: Overcurrent protection shall be permitted at the source or for the equipment, provided the overcurrent protection complies with the requirements of 700.28.

WARNING CONDUCTOR ELECTRODE GROUNDING IF EXISTS HAZARD SHOCK IS EQUIPMENT THIS IN CONNECTION JUMPER BONDING OR REMOVED WHILE ALTERNATE SOURCE(S) IS ENERGIZED. The warning sign(s) or label(s) shall comply with 110.21(B). 700.8 Emergency Sources A listed SPD shall be installed in or on all emergency panelboards. and switchboards systems Wiring Circuit II. System. Emergency Wiring, 700-10. (A)

(B) (B) Exception: A sign shall not be required for individual for required be not shall sign A Exception: unit equipment as specified in Section 700-12(F). (B) Informational Note: For signals for generator sets, see NFPA 110- 2013, Standard for Emergency and Standby Power Systems 700.7. Signs (A) GENERAL INFO 172 National Code Electrical — (3) (1) Set. Generator (B) provided. be shall means charging battery automatic An furnished. batteries shall Automotive-type not be used. be shall containers translucent or transparent additions, water requires that battery acid lead the for However, transparent. be to required be not shall container the battery, asealed For installation. particular that for charger the with compatible be shall and service emergency of requirements the meet to constructed and designed be shall type, alkali or acid the of whether Batteries, normal. of percent 87-1/2 below falling load the to applied voltage the without minimum, hours 1-1/2 of aperiod for load total the maintain and supply to capacity and rating suitable of be shall systems emergency for power of source as used batteries Storage Battery. Storage (A) Reliable Industrial andCommercial Power Systems. Practice for theDesign of Recommended 493-2007, IEEE ANSI/ see information, further For 2: No. note Informational (6) (6) (5) (4) company. utility electrical outside the from power and system delivery fuel off-site the both of failure asimultaneous of probability alow is there where permitted be shall fuels on-site than other of use the jurisdiction, having authority the to acceptable Where Exception: (2)

P case of short-time reestablishment of the normal source. normal the of reestablishment short-time of case in retransfer avoid to provided be shall setting a 15-minute permitting feature Atime-delay circuits. electrical required all of operation and transfer automatic for and service normal the of failure on mover prime the starting automatically for provided be shall Means 700-4. Section with accordance in sized and jurisdiction having authority the to acceptable mover pump shall be connected to the emergency power system. power emergency the to connected be shall pump this tank, dry set agenerator to fuel deliver to pumps transfer fuel the of operation the for needed is power Where system. the of operation full-demand 2hours than less not for sufficient supply fuel on-premise an with provided be shall supply fuel on-site an mover prime the as used are engines combustion I D fuel supply to another where dual fuel supplies are used. are supplies fuel dual where another to supply fuel one from transferring automatically for provided be shall Means systems. cooling their for supply water municipal or supply fuel their for system gas utility apublic upon  W the dampers shall be connected to the emergency system. emergency the to connected be shall dampers the set, generator the ventilate to used dampers of operation the for required is power Where system. emergency the to connected be shall it set, generator the of operation the for required is charger battery the Where set. generator the of independent means charging automatic an with equipped be shall and purpose the for suitable be shall it mover, prime the starting of means the as A  system until the generator can pick up the load. the up pick can generator the until system emergency the energizes supply power auxiliary an is permitted be shall power develop to seconds 10 than disconnecting means shall meet the requirements of 225.36. the structure, or abuilding on or in means adisconnecting at terminate conductors supply generator the Where structure. or building the through pass or serve conductors ungrounded where required be not shall means disconnecting additional an supplied, structure or building the of sight within located is means disconnecting the and 445.18, with accordance in means disconnecting accessible areadily with equipped is set  O nternal Combustion rime Mover-Driven. uxiliary Power Supply. ual Supplies. Where an outdoor housed generator generator housed outdoor an Where Sets. Generator utdoor here a storage battery is used for control or signal power, or or power, signal or control for used is battery astorage here Prime movers shall not be solely dependent dependent solely be not shall movers Prime For a generator set driven by a prime aprime by driven set agenerator For Engines as Prime Movers. Where internal EMERGI-LITE Generator sets that require more more require that sets Generator ACCESSORIES INFORMATION & GENERAL (2) (2) (1) (F) system. standby emergency the for power of source sole the as serve not shall it concerned, buildings of group or building the for supply normal the as serves system cell fuel asingle Where 692. Article of VIII through II Parts of requirements the meet shall system cell afuel of Installation (E) (D) (C) served. structure of building the of sight within located be to required disconnection, the generator set disconnecting means shall not be safe switching procedures are established and maintained for documented where and installation the service and monitor will persons qualified only that ensure supervision and maintenance of Exception: For installations under single management where conditions

branch circuit for unit equipment shall be permitted if it it if permitted be shall equipment unit for circuit branch aseparate circuits, lighting normal three of aminimum by supplied area uninterrupted and aseparate :In Exception

for illumination emergency shall consist of the following:  C installed in accordance with 700.12(F)(2)(1) through (6). through 700.12(F)(2)(1) with accordance in installed  I  U not less than 2 hours of full demand operation. demand full of 2hours than less not for load total the maintain and supply to capacity and rating suitable of be shall systems emergency for power  F with the applicable provisions of Sections 700-12(A) and (B). and 700-12(A) Sections of provisions applicable the with comply shall systems emergency for power provide to used U (2) (1) (4) (3) (2) (1) ( ( ( Article 230 and 230 Article following additional requirements. of provisions applicable the with accordance in be shall service This permitted. be shall service additional an power, of source emergency an as use for suitable as jurisdiction S Unit equipment shall be be shall equipment Unit Equipment. Unit of nstallation 1) 1) 2) 2) 3) 3) Individual unit equipment equipment unit Individual Equipment. Unit of omponents uel Cell System. Where acceptable to the authority having having authority the to acceptable Where Service. eparate nit Equipment. nit ninterruptible Power Supplies.

A rechargeable battery

A battery charging means

to meet the requirements of emergency service. emergency of requirements the meet to constructed and designed be shall type, alkali or acid the of whether batteries, Storage hours. 1-1/2 least at of aperiod for illumination emergency initial the of percent 60 than less not maintain and supply shall equipment unit the or hours, 1-1/2 least at of aperiod for unit the with associated load lamp total the for voltage battery nominal the of percent 87-1/2 than less not at maintain and supply T  provided that the cord does not exceed 900 mm (3 ft) in length. in ft) (3 mm 900 exceed not does cord the that provided permitted, be shall connection plug and cord Flexible 3. Chapter in methods wiring the of any of requirements the with accordance in installed unit each to wiring all have shall and portable)  U S service laterals shall be installed be shall laterals service or conductors, service underground drops, the area and connected ahead of any local switches. local any of ahead connected and area the in lighting normal the serving that as circuit branch same T possibilit of simultaneous interruption of supply the minimize to conductors service other any from installed remote sufficiently and electrically physically T terminals for remote lamps, or both and both or lamps, remote for terminals have to permitted be shall or equipment, the P upon failure of the supply to the unit equipment. unit the to supply the of failure upon A r he batteries shall be of suitable rating and capacity to to capacity and rating suitable of be shall batteries he eparate overhead service conductors, service service conductors, service overhead eparate he branch circuit feeding the unit equipment shall be the the be shall equipment unit the feeding circuit branch he he service conductors for the separate service shall be be shall service separate the for conductors service he rovisions for one or more lamps mounted on nit equipment shall be permanently fixed in place (i.e., not not (i.e., place in fixed permanently be shall equipment nit elaying device arranged to energize the lamps automatically automatically lamps the energize to arranged device elaying Fuel Cell Systems used as a source of of asource as used Systems Cell Fuel Uninterruptible power supplies GENERAL INFO 173 The alternate alternate The The branch circuit The switch or switches installed in A dimmer or relay system containing more All manual switches for controlling emergency controlling for switches manual All The branch-circuit overcurrent devices in ultiwire Branch Circuits. witch Requirements. witch  emergency lighting circuits shall be arranged so that only authorized persons will have control of emergency lighting. S  serving emergency lighting and power circuits circuits power serving and emergency lighting shall not be part of a multiwire branch circuit. M

Switch Location. Switch

700.19. 700.20. source for emergency systems shall not be required to have ground- fault protection of equipment with automatic disconnecting means. Ground-fault indication of the emergency source shall be provided in accordance with 700.6(D)if ground-fault protection of equipment with automatic disconnecting means is not provided. required be not shall Selective coordination Exception: between two overcurrent devices located in series if no loads are connected in parallel with the downstream device. National Electrical Code© 2014 National Electrical Code® is a Association. Protection Fire National the of trademark registered Exception No. 1: Where two or more single-throw switches are connected in parallel to control a single circuit, at least one of these switches shall be accessible only to authorized persons. Exception No. 2: Additional switches that act only to put emergency lights into operation but not disconnect them shall be permissible. Switches connected in series or 3- and 4-way switches shall not be used. 700.21. circuits shall be in locations convenient to authorized persons responsible for their actuation. In facilities covered by Articles 518 and 520, a switch for controlling emergency lighting systems shall be located in the lobby or at a place conveniently accessible thereto. In no case shall a control switch for emergency lighting be placed in a motion-picture projection booth or on a stage or platform. Exception: Where multiple switches are provided, one such switch shall be permitted in such locations where arranged so that it can energize the circuit only, but cannot deenergize the circuit. 700.22. Exterior Lights. Those lights on the exterior of a building that are not required for illumination when there is sufficient daylight shall be permitted to be controlled by an automatic light-actuated device. Systems. Dimmer 700.23 than one dimmer or relay and listed for use in emergency systems shall be permitted to be used as a control device for energizing emergency lighting circuits. Upon failure of normal power, the dimmer or relay system shall be permitted to selectively energize only those branch circuits required to provide minimum emergency illumination. All branch circuits supplied by the dimmeror relay system cabinet shall comply with the wiring methods of Article 700. 700.24 Automatic Load Control Relay. emergency illumination Where is provided by one or more directly controlled luminaires that respond to an external control input to bypass normal control upon loss of normal power, such luminaires and external bypass controls shall be individually listed for use in emergency systems. 700.25 Automatic Load Control Relay. If an emergency lighting load is automatically energized upon loss of the normal supply, a listed automatic load control relay shall be permitted to energize the load. The load control relay shall not be used as transfer equipment. VI. Overcurrent Protection Accessibility. 700-26. emergency circuits shall be accessible to authorized persons only. Equipment. of Protection Ground-Fault 700-27. NATIONAL ELECTRICAL CODE ELECTRICAL NATIONAL Emergency iillumination shall include all all include shall Emergency iillumination ircuits for Emergency Power. For branch circuits that ranch Circuits for Emergency Lighting.Branch circuits emote heads providing lighting for the exterior of an exit mergency luminaire’s (illumination fixtures) that obtain power power obtain that fixtures) (illumination mergency luminaire’s he branch circuit that feeds unit equipment shall supply equipment classed as emergency, there shall bean emergency supply source to which the load will be transferred automatically upon the failure of the normal supply.  C  that supply emergency lighting shall be installed to provide service from a source complying with Section 700-12 when the normal supply for lighting is interrupted. Such following: the of one either provide shall installations B . door shall be permitted to be supplied by the unit equipment door exit the inside immediately serving area the  R from a unit equipment and are not part of the unit equipment shall be wired to the unit equipment as required by Section 700-10 and by one of the wiring methods of Chapter 3.  E  be clearly identified at the distribution panel. T . n emergency lighting supply, independent of the normal lighting lighting normal the of independent supply, emergency lighting n wo or more branch circuits supplied from separate and 5) 5) 6) 4) 4) ( ( (  complete systems with independent power sources. One of the two power sources and systems shall be part of the emergency system and the other shall be permitted to be part of the normal power source and system. Each system shall purposes. lighting emergency for sufficient power provide T  supply, with provisions for automatically transferring the emergency lights upon the event of failure of the normal lighting branch circuit A

V. Control—Emergency Lighting Circuits Control—Emergency Lighting V. (2) (1) IV. EmergencyIV. System Circuits for Lighting and Power 700.15. Loads on Emergency Branch Circuits. No appliances and no lamps, other than those specified as required for emergency use, shall be supplied by emergency lighting circuits. 700.16. Unless both systems are used for regular lighting purposes and are both kept lighted, means shall be provided for automatically energizing either system upon failure of the other. Either or both systems shall be permitted to be a part of the general lighting of the protected emergency illumination for lights supplying circuits if occupancy arc installed in accordance with other sections of this article. 700.18 Emergency Emergency illumination. required means of egress lighting, illuminated exit signs, and all illumination. other required provide to necessary as specified lights Emergency lighting systems shall be designed and installed so that the failure of any individual lighting element, such as the burning out of a light bulb, cannot leave in total darkness emergency illumination. requires that space any Where high-intensity discharge lighting such as high- andlow-pressure sodium mercury vapor, and metal halide is used as the sole source of normal illumination, the emergency lighting system shall be required to operate until normal illumination has been restored. Where an emergency system is installed, emergency illumination shall be provided in the area of the disconnecting means required by 225.31 and 230.70, indoors. installed are means disconnecting the where applicable, as Exception: Where alterative means that ensure the emergency lighting illumination level is maintained shall be permitted. 700.17 

originates from the same panelboard as that of the normal lighting circuits and is provided with a lock-on feature.