White Paper National Electrical Code (NEC) Requirements for Surge Protective Devices

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1 White Paper National Electrical Code (NEC) Requirements for Surge Protective Devices

2 National Electrical Code (NEC) Requirements for Surge Protective Devices In the United States, The National Electrical Code (NEC ) sets forth installation requirements for electrical systems and equipment, including Surge Protective Devices (SPDs). 1 The NEC provides guidance regarding where SPDs should and should not be used and how they may be installed in electrical power distribution systems. The following narrative identifies and describes key provisions of the NEC. CODE ADOPTION In any review of the NEC, it is important to understand its revision and adoption process. The NEC is revised once every three years, then republished as a new edition. In the United States, any new edition becomes effective locally after it is formally adopted by a state or local agency having jurisdiction. Because the timing of adoption by each state differs, four different editions of the NEC were in effect in the United States on August 1, In addition, three states had not adopted any edition for state-wide use. The status of effective editions is shown in Figure 1. WA OR N CA ID AZ UT MT WY CO NM ND SD NE KS OK NH T ME MN MA WI NY MI RI IA PA CT IL IN OH NJ DE Win MD A MO KY NC TN AR SC AK TX LA MS AL GA FL HI 2017 NEC 2014 NEC 2011 NEC 2008 NEC No Statewide NEC Adoption Figure 1: National Electrical Code Editions in Effect on August 1, National Fire Protection Association, NFPA 70 - National Electrical Code, Fourteenth Edition, Quincy, Massachusetts, National Fire Protection Association, National Electrical Code in Effect August 1, viewed 8/28/18. 2

3 A N C B Most states that have not adopted the latest version of the NEC have initiated a review process for adopting an edition of the code. While the latest edition of the code may not be required locally when a project is designed, many NEC changes are made to improve safety. Because updates typically do not conflict with older provisions, designing to the latest edition can improve overall facility design. Applicable local codes should also be reviewed. For instance, Pennsylvania currently uses the 2008 NEC, and is presently reviewing the 2014 edition for adoption. When planning projects, it is important to know the edition in effect for the project location and to monitor the status of adoption processes in the project location. ESSENTIAL NEC PROISIONS Article 285 Surge Protective Devices Essential provisions regarding SPDs have been part of the NEC through several editions. Added in 2002 and amended thereafter, Article 285 Surge Protective Devices, 1000 olts or Less describes types of SPDs and the corresponding locations for their installation. The article also presents basic but important provisions regarding the use of SPDs. These include requirements to connect SPDs to each ungrounded connector at the point of use; 3 installing only listed SPDs; 4 and using leads that are no longer than necessary and avoiding unnecessary bends. 5 Article 285 also prohibits certain uses of SPDs, and prohibits installing SPDs where voltages or fault currents exceed device ratings. 6,7 Those ratings include the Short- Circuit Current Rating required by Article These ratings can be found on a manufacturer s product data sheet. A data sheet example is shown in Figure 2. Performance Specifications Figure 1 Neutral (White) Phase B (Black) Performance Data Model 570 Number Configurator & Options 570 Model 570 Product Line Optional rotary disconnect switch may increase PRs Figure 2 Phase B (Black) Neutral (White) oltage Codes Figure 3 Phase B (Orange) Neutral (White) P A Per Phase ka Rating System Common Systems 120S = 240/120 Split Phase - 1Ø, 3W+Grnd, (Fig 1) 120Y = 208Y/120 Wye - 3Ø 4W+Grnd, (Fig 2) 240H = 240/120 High Leg Delta (B High), (Fig 3) 277Y = 480Y/277 Wye - 3Ø 4W+Grnd, (Fig 2) 480D = 480 Delta - 3Ø 3W+Grnd, (Fig4) & HRG Wye Other Available Systems - Confirmation Encouraged 120N = 120 Single Phase (Fig 5) 208D = 208 Delta - 3Ø, 3W+Grnd (Fig 4) 230Y = 400Y/230 Wye - 3Ø 4W+Grnd (Fig 2) 230N = 230 Single Phase (Fig 5) 240N = 240 Single Phase (Fig 5) - Not split phase 240C = 240 B Corner Grnd Delta, 3Ø 3W+Grnd (Fig 6) 240D = 240 Delta - 3Ø 3W+Grnd (Fig 4) 277N = 277 Single Phase (Fig 5) 277S = 480/240 Split Phase, or Two legs of Wye, (Call) 400D = 400 Delta - 3Ø, 3W+Grnd (Fig 4) 480C = 480 B Corner Grnd Delta, 3Ø 3W+Grnd (Fig 6) 480H = 480/240 High Leg Delta (B High), (Fig 3) Surge Capacities L-N L-G N-G 250kA Per Phase (125kA Per Mode) 125kA 125kA 125kA 320kA Per Phase (160kA Per Mode) 160kA 160kA 160kA 400kA Per Phase (200kA Per Mode) 200kA 200kA 200kA 500kA Per Phase (250kA Per Mode) 250kA 250kA 250kA 750kA Per Phase (375kA Per Mode) 375kA 375kA 375kA UL 1449 Fourth Edition Listed Type 1 or Type 2 UL 1449 Fourth Edition tested Inominal (I n ): 20kA UL 1449 Fourth Edition tested SCCR: 200kA B D.44 [11.1] UL 1449 Fourth Edition oltage Protection Ratings (PRs): 208Y/120: as low as Y/277: as low as 1000 (data table on back) EMI/RFI Filtering Noise Rejection: 63dB Maximum UL 1449 Type 2 SPD (UL 1283) 25dB Maximum UL 1449 Type 1 SPD Less than 1 nanosecond response time Diagnostic Monitoring 100% monitoring Every SAD & MO is monitored, including N-G Green LED Status indicator per phase (Redundant LEDs on modules) Red LED service indicator A C 9.0 [229] ka Rating Per Phase 25 = 250kA Per Phase (125kA Per Mode) 32 = 320kA Per Phase (160kA Per Mode) 40 = 400kA Per Phase (200kA Per Mode) 50 = 500kA Per Phase (250kA Per Mode) 75 = 750kA Per Phase (375kA Per Mode) Figure 4 Modes of Protection A = All Standard Modes for that oltage Code (Default) Delete Mode Options & Alt. Configurations: Contact Factory Phase B (Black) Connection Type C = Compression Lugs (Default) T = Through-Door Rotary Disconnect Switch Monitoring Options Enclosure UL 1449 Type1/Type 2 G = NEMA 1/12/3R/4 Steel H = NEMA 4X Stainless Steel (Display Inside Door) N = No Enclosure - open style for custom mounting within another enclosure A = Green & Red LEDs, Audible Alarm w/silence Switch, Two sets of Dry Contact Relays C = A (above) plus Surge Counter D = A (above) plus Dual Surge Counters T = Active Surge Monitor (See Pub. DS & SL-70109) Figure 5 SPLIT L-N Split Phase = 208Y/120 3Ø Wye 240H = 240/120 B High Leg Delta 277Y = 480Y/277 3Ø 480D = 2 Phases, 1 Neutral, 1 Ground WYE HIGH LEG DELTA DELTA & HRG WYE SINGLE POLE 3 Phases, 1 Neutral, (B High) 3 Phases, 3 Phases, 1 Ground 1 1 Ground (B High), 1 Neutral, 1 Ground Common Power Systems Phase, 1 Neutral, 1 Ground UL 1449 Fourth Edition Test Data oltage Protection Ratings (PR - 3kA) L-G N-G S = 240/ Y / n SCCR / kA 200kA kA MCO Wye 480 Delta / L-L I 20kA 200kA 150 / kA 200kA kA 200kA kA Built-in Automated Test Function, Audible Alarm with Silence Switch Form C Dry Contacts, Two Sets, 250, 5A Optional Surge Counter & Dual Surge Counters; 6 digit, w/test & reset Available Active Surge Monitor (ASM), see pub. DS & SL Physical Specifications Relative Humidity Range: 0 95% non-condensing Operating Frequency: 47-63Hz Maximum Operating Temperature: 85 C (185 F) Standard NEMA 1/12/3R/4 Steel Enclosure Size/Weight vary by Surge Capacity & Disconnect Switch: Min: 16 x 12 x 9 (406mm x 305m x 229mm), 35lbs (16kg) Max: 20 x 20 x 9 (508mm x 508mm x 229mm), 85lbs (39kg) ASCO Power Technologies th St. North, Clearwater, FL Lug size: #14 - #1/0 AWG (Optional Disconnect: #8 - #1/0 AWG) Typical connection: #4 AWG and 30-70A circuit breaker Benefits: SAD/MO Hybrid UL 1449 Fourth Edition Listed 250kA 750kA per phase ratings (125kA-375kA per mode) All UL required OCP & Safety Coordination included inside Type 1 SPDs intended for Line or Load Side of Main Disconnect Type 2 SPDs intended for Load Side of Main Disconnect 20kA Inominal 200kA SCCR UL 96A Lightning Protection Master Label compliant Redundant Replaceable Module Design Optional Rotary Disconnect Switch oltage Specific Design Highly configurable All SAD and MO suppression elements monitored All Modes of Protection 10 Year Parts, 5 Year Labor Warranty (longer optional) Design Attributes Neutral (White) Figure 6 CORNER GROUND DELTA (B grounded) 2 Phases, 1 Ground surge.ascopower.com customercare@ascopower.com Copyright May Publication DS RevL 1 = UL 1449 Type 1 2 = UL 1449 Type 2, (Includes UL1283 Filter and cul Marking for Canada) 0 = No Trailing Accessory/Option X = Yes Trailing Accessory/Option Contact factory for other options such as Remote Display Harness length for custom installations. Surge Rating Connection Type A x B C D Weight 125kA 160kA-200kA Wire Lug 16 x 12 (406 x 305) (438) 9.5 (241) 35lb (15.9kg) Disconnect Wire Lug 500 SERIES Model 570 Data Sheet Designed, Manufactured & Tested consistent with: ANSI/IEEE C , C , C , C , C , IEEE SA (Emerald Book) NEC Article 285 NEC Articles (E), , 670.6, , & 708 requiring SPDs UL 96A and NFPA 780 Lightning Protection High Energy Parallel Design for Category C High applications For External Mounting on Electrical Distribution Equipment, Switchgear, Switchboards, Motor Control Centers, Panelboards, Transfer Switches, etc. Individually Fused & Thermally Protected SADs and MOs Robust 25mm round Phenolic Coated MO Construction Heavy-Duty Axial-leaded Silicon Avalanche Diodes (SADs) With Precision Inductive Transitioning Circuitry Solid State Bidirectional SADs and MOs Third Party Testing Single Impulse Tested - Third Party erified (former NEMA LS-1 style). To Each Mode s Rating Up To Surge Generator Limit Of 200kA 16 x 16 (406 x 406) (438) 10 (254) 45lb (20.4kg) Disconnect 20 x 16 (508 x 406) (540) 10 (254) 55lb (24.9kg) Life Cycle Surge Testing (Repetitive Impulse Testing): 250kA 15,000 IEEE C High 20k, 10kA impulses Per Mode 30,000 IEEE C High 20k, 10kA impulses Per Phase 320kA-500kA 30,000 IEEE C High 20k, 10kA impulses Per Mode 60,000 IEEE C High 20k, 10kA impulses Per Phase 750kA-1000kA 45,000 IEEE C High 20k, 10kA impulses Per Mode 90,000 IEEE C High 20k, 10kA impulses Per Phase Quality, Standards & alidation Type 1 UL 1449 Fourth Edition Type 2 (Opt.) UL 1449 Fourth Edition, UL 1283, cul for Canada UL file: ZCA.E Burn-in tested prior to shipment ISO 9001:2008 Quality Management System ISO 17025:2005 Laboratory Qualification Accessory/ Option(s) Figure 2: Manufacturer s data sheets provide ratings for each SPD model. 3 National Fire Protection Association, NFPA 70 - National Electrical Code, Fourteenth Edition, Quincy, Massachusetts, p Ibid. 5 Ibid. p Ibid. p Ibid. 3

4 Article Critical Operations Power Systems In 2008, Article Critical Operations Power Systems (COPS) was added to the NEC in response to events such as terrorist attacks and hurricanes in the United States. Article defines COPS as, Power systems for facilities or parts of facilities that require continuous operation for the reasons of public safety, emergency management, national security or business continuity. 8 Examples of facilities that utilize COPS include hospitals, data centers, police stations, call centers, or critical portions of larger facilities. Important provisions for these facilities include: (D) - Surge Protective Devices, which states, Surge protective devices shall be provided at all facility distribution voltage levels (4) - Wiring of HAC, Fire Alarm, Security, Emergency Communications and Signaling Systems, which states, Listed secondary protectors shall be provided at the terminals of the communication circuits. 10 Installation of SPDs in a power system regulated by Article 708 must support the selective coordination practices applied to overcurrent devices, which must be specified by a professional engineer or other qualified person. Specific requirements are provided in Article SUBSEQUENT NEC CHANGES In October of 2014, the Fire Protection Research Foundation issued a document entitled, Data Assessment for Electrical Surge Protection Devices - Phase 1, Final Report. 12 This report surveyed and summarized the impacts of transient overvoltages to electrical power distribution systems and equipment. The findings influenced the development and adoption of new NEC Code articles requiring SPDs to be installed to protect the emergency power system of regulated facilities. The most important 2014 and 2017 NEC changes regarding SPDs include those in the following sections. 4 8 Ibid. p Ibid. p Ibid. 11 Ibid. p Fire Protection Research Foundation, Data Assessment for Electrical Surge Protection Devices - Phase 1, Final Report. Quincy, Massachusetts, 2016

5 Article 700 The provisions of Article Emergency Systems apply to electrical safety emergency systems consisting of circuits and equipment intended to supply, distribute, and control electricity for illumination, power, or both, to required facilities when the normal electrical supply or system is interrupted. 13 Circuits and equipment that provide illumination, ventilation, elevator, fire alarm, and fire pump functions to allow occupants to safely exit a building are all examples of Emergency Systems under Article 700. Within the section, Article Surge Protection requires that a listed SPD be installed in or on the switchboards and panelboards of all emergency systems to protect equipment from hazards associated with transient overvoltages. 14 The article does not further specify the characteristics of SPDs that should be used. Because Article 517 Healthcare Facilities references Article 700, certain systems in healthcare facilities are impacted by Article 700 provisions. Article states, The life safety branch of the essential electrical system shall meet the requirements of Article 700, except as amended by Article To understand the reference, it is important to understand how Article 517 defines the Life Safety Branch, which is shown in Figure 3 as part of a facility s Essential Electrical System. Normal Source Emergency Source ATS ATS ATS Non-Essential System Equipment Branch Life Safety Branch Critical Branch Essential Electrical System Figure 3: The Life Safety Branch is best understood in the context of the Essential Electrical System that Article 517 defines for healthcare facilities. The NEC defines the Life Safety Branch as, A system of feeders and branch circuits supplying power for lighting, receptacles, and equipment essential for life safety that is automatically connected to alternate power sources by one or more transfer switches during interruption of the normal power source. 16 Examples of equipment served by the Life Safety Branch include: illumination for egress exit signage alarm and alerting systems communications systems generator locations and generator accessories elevators automatic doors Consequently, these systems must be protected by installing SPDs on the panelboards and switchboards that serve them. 13 National Fire Protection Association, NFPA 70 - National Electrical Code, Fourteenth Edition, Quincy, Massachusetts, p Ibid. p Ibid. p Ibid. p

6 OTHER IMPORTANT PROISIONS Article Elevators, Dumbwaiters, Escalators, Moving Walks, Platform Lifts, and Stairway Chairlifts Article 620 sets for requirements elevators, dumbwaiters, escalators, moving walks, platform lifts, and stairway chairlifts, and was updated in the 2017 Edition. Within the section, Article provides various requirements for the disconnecting means that must be provided for this equipment. It further states, Where any of the disconnecting means in has been designated as supplying an emergency system load, surge protection shall be provided. 17 Article Critical Operations Data Systems Article defines a Critical Operations Data System as, An information technology equipment system that requires continuous operation for reasons of public safety, emergency management, national security, or business continuity. Article requires surge protection for all such systems. 18 Article 670 Industrial Machinery Article 670 addresses the definition of, the nameplate data for, and the size and overcurrent protection of supply conductors to industrial machinery. 19 Because electronic safety devices must be able to protect people from injury at all times, installing surge protection protect devices can protect equipment from surges to help ensure proper and safe operation. Article thus requires that industrial machinery with electronic interlocks must have surge protection devices installed. Article 695 Fire Pumps Other electronic safety devices that must work when needed include fire pumps that supply fire suppression systems. Article states, A listed surge protective device shall be installed in or on the fire pump controller. An ASCO Power Technologies Fire Pump Controller is shown in Figure 4. SUMMARY Triennial revisions to the NEC make it important to track the editions of the code that is in effect for a project location. The NEC articles referenced herein constitute the bulk of requirements regarding the location and use of SPD in power distribution system. A look-up table summarizing key SPD-related NEC requirements is provided as follows. Key 2017 NEC Surge Protection Provisions Article Application Requirements 285 Surge Protective Devices 285.4, 285.6, , 285.3, Healthcare Facilities 517.2, Elevators/Escalators IT/Data Systems Industrial Machinery Fire Pumps Emergency Systems 700.1, Critical Operations Power Systems 708.2, (D), (4) Figure 4: Providing SPDs on fire pump controllers helps ensure reliable operation during an emergency event Ibid. p Ibid. p Ibid. p. 540.

7 ASCO Power Technologies - Global Headquarters 160 Park Avenue Florham Park, NJ Tel: ASCO customercare@ascopower.com Surge Protection th Street North Clearwater, FL Tel: (U.S & Canada Only) (Outside U.S.) Fax: WP (r- 09/18) surge.ascopower.com whitepapers.ascopower.com ASCO Power Technologies. All Rights Reserved. ASCO. Innovative Solutions. 7