1、 Evaluating Fire- and Heat-Damaged Electrical Equipment www.nema.org 2016 National Electrical Manufacturers Association Page 1 1 USE OF THIS PUBLICATION This publication serves as a guideline that represents the consensus of NEMA member companies and is not intended to override the recommended guida
2、nce of the specific equipment manufacturer. These guidelines provide information on how to evaluate electrical equipment that has been exposed to heat and fire residue through fire, firefighting activities, or close proximity to a fire. It is designed for use by suppliers, installers, inspectors, an
3、d users of electrical products. Where additional information is required, it is recommended that the specific electrical equipment manufacturers be consulted. Evaluation of electrical equipment should be conducted by qualified personnel. Electrical equipment exposed to heat and fire residue can be e
4、xtremely hazardous if re-energized without first performing a proper evaluation and taking necessary action. Reduction in the integrity of electrical equipment due to heat degradation of materials, residue from burning materials, or moisture can affect the ability of the equipment to perform its int
5、ended function and be used safely. Damage to electrical equipment can also result from airborne contaminates containing chemicals and other debris, which can affect the integrity and performance of the equipment. Smoke and soot from burning materials can be particularly damaging because of the corro
6、sive and conductive nature of the residue. Damage caused by fire-suppression activities, structural damage, and weather exposure must also be considered. Distributors of electrical equipment should not supply any inventory that has been damaged by fire or heat. Doing so can lead to the use of damage
7、d equipment that may not function correctly, creating a hazard to individuals or property. 2 CONTACT THE MANUFACTURER A working knowledge of electrical systems and the equipment in question is required to evaluate damage related to a fire event. The original manufacturer of the equipment should be c
8、ontacted if any questions arise or specific recommendations are needed. In many cases, equipment replacement will be necessary. After consultation with the manufacturer, some larger types of electrical equipment may be reconditioned by properly trained personnel. The potential for reconditioning can
9、 vary with the nature of the electrical function, the significance of the heat and fire residue, the age of the equipment, and the length of time the equipment was exposed to excessive heat or other damaging conditions. Because other damage to affected equipment can occur (e.g., chemical or structur
10、al damage), the equipment subject to the stresses of exposure to fire and/or heat needs to be carefully examined and evaluated to ensure that safety and performance are not negatively impacted. Attempts to recondition equipment without consulting the manufacturer can result in additional hazards due
11、 to the use of improper cleaning agents, which can further damage the equipment (see National Electrical Code NECSection 110.11, Informational Note No. 2) or due to improper reconditioning techniques. NEMA member companies are committed to safety. For specific contacts within these manufacturing fir
12、ms, call or write: National Electrical Manufacturers Association 1300 North 17th Street, Suite 900 Rosslyn, Virginia 22209 Telephone: (703) 841-3236; Email: vin_baclawskinema.org ATTN: Vince Baclawski Page 2 2016 National Electrical Manufacturers Association 3 ELECTRICAL EQUIPMENT REPLACEMENT AND RE
13、CONDITIONING REQUIREMENTS The table below shows the requirements and recommendations associated with replacing or reconditioning various categories of electrical equipment that have been subjected to damage as a result of a fire event. Where it is shown that the equipment has “potential for recondit
14、ioning,” it is critical that the equipment manufacturer is contacted for specific guidance. Equipment Replace equipment Potential for reconditioning (contact the manufacturer) Additional standards reference (if available) ELECTRICAL DISTRIBUTION EQUIPMENT (refer to 4.1) Molded-case circuit breakers
15、X ANSI/NEMA AB 4-2009 Guidelines for Inspection and Preventive Maintenance of Molded-Case Circuit Breakers Used in Commercial and Industrial Applications Low-voltage fuses X Enclosed switches X NEMA KS 3-2010 Guidelines for Inspection and Preventive Maintenance of Switches Used in Commercial and Ind
16、ustrial Applications Busway (Mylar-wrapped bars) X NEMA BU 1.1-2005 General Instructions for Handling, Installation, Operation, and Maintenance of Busway Rated 600 V or Less Busway (powder-coated bars) X Panelboards X NEMA PB 1.1-2013 General Instructions for Proper Installation, Operation, and Main
17、tenance of Panelboards Rated 600 Volts or Less, par. 10.3, 10.7, 10.8, 10.8.3, 10.8.4, 10.9 Transfer switches X NEMA ICS 10-2005 Industrial Controls and Systems, Part 1: Electromechanical AC Transfer Switch Equipment Switchboards X NEMA PB 2.1-2013, General Instructions for Proper Handling, Installa
18、tion, Operation and Maintenance of Deadfront Distribution Switchboards Rated 600 Volts or Less, par. 9.1, 9.7, 9.8, 9.8.3, 9.8.4, 9.9 2016 National Electrical Manufacturers Association Page 3 Equipment Replace equipment Potential for reconditioning (contact the manufacturer) Additional standards ref
19、erence (if available) MOTOR CONTROL EQUIPMENT (refer to 4.2) Adjustable speed drives X Components containing semiconductors and transistors X Electronically controlled and solid-state contactors and starters X Overload relays X Manual and magnetic controllers X Motor control centers X POWER EQUIPMEN
20、T (refer to 4.3) Electronic trip units of LV power circuit breakers X High-voltage power circuit breakers (AC) X Medium-voltage power circuit breakers Low-voltage power circuit breakers X Protective relays and meters (electromechanical) Protective relays and meters (electronic/digital) X Low-voltage
21、 switchgear X Medium-voltage switchgear X Medium-voltage fuses X TRANSFORMERS (refer to 4.4) All dry-type transformers, regardless of kVA ratings X All dry-type control circuit transformers X Liquid-filled transformers X (Analysis of the insulating medium is required for evaluation of this equipment
22、) Cast-resin transformers X CONDUIT, TUBING, FITTINGS, OUTLET BOXES, AND JUNCTION BOXES (refer to 4.5) Fittings X NEMA FB 1-2007(R2010) Fittings, Cast Metal Boxes, and Conduit Bodies for Conduit, Electrical Metallic Page 4 2016 National Electrical Manufacturers Association Equipment Replace equipmen
23、t Potential for reconditioning (contact the manufacturer) Additional standards reference (if available) Tubing (EMT), and Cable Outlet and junction boxes X NEMA OS 1-2008 (R2010) Sheet-Steel Outlet Boxes, Device Boxes, Covers, and Box Supports NEMA OS 2-2008 Nonmetallic Outlet Boxes, Device Boxes, C
24、overs, and Box Supports Conduit and tubing X WIRE, CABLE, AND FLEXIBLE CORDS (refer to 4.6) Wire, cable, and flexible cords X AFCIs, GFCIs, SURGE-PROTECTIVE DEVICES, AND WIRING DEVICES (refer to 4.7) Arc-fault circuit interrupters (AFCIs) and ground-fault circuit interrupters (GFCIs) X ANSI/NEMA AB
25、4-2009 Guidelines for Inspection and Preventive Maintenance of Molded-Case Circuit Breakers Used in Commercial and Industrial Applications Surge-protective devices (transient voltage surge suppressors, surge arresters, lightning arresters) X Wiring devices (switches, receptacles, dimmers, etc.) X OT
26、HER DEVICES Batteries (refer to 4.12) X Cable tray (refer to 4.8) X (Replace damaged labels) Fire pump controllers X NEMA ICS 15-1999 (R2004) Instructions for the Handling, Installation, Operation, and Maintenance of Electric Fire Pump Controllers Rated Not More Than 600V Luminaires (lighting fixtur
27、es) (refer to 4.9) X Motors (refer to 4.10) X ANSI/IEEE 43-2013, A2, and A3 2016 National Electrical Manufacturers Association Page 5 Equipment Replace equipment Potential for reconditioning (contact the manufacturer) Additional standards reference (if available) Fire-detection, signaling, protectio
28、n, and communications systems (refer to 4.11) X Uninterruptible power supply (UPS) equipment X 4 THE HAZARDS ASSOCIATED WITH FIRE- OR HEAT-DAMAGED ELECTRICAL EQUIPMENT 4.1 Electrical Distribution Equipment Electrical distribution equipment usually involves switches and low-voltage protective compone
29、nts, such as molded-case circuit breakers and fuses within assemblies (enclosures, panelboards, and switchboards, for example). These assemblies can be connected to electrical distribution systems using various wiring methods. The protective components are critical to the safe operation of distribut
30、ion circuits. Their ability to protect these circuits is adversely affected by exposure to fire or heat and the potential reduction in the integrity of electrical equipment due to heat degradation of materials, residue from burning materials, or moisture. In molded-case circuit breakers and switches
31、, such exposure can affect the overall operation of the mechanism through contaminants, the presence of foreign particles, and loss of lubrication. The condition of the contacts can be affected, and the dielectric insulation capabilities of internal materials can be reduced. Further, some molded-cas
32、e circuit breakers are equipped with electronic trip units, whose functioning can be impaired. Fire or heat can affect the fuse tube and the filler material of fuses, degrading the insulation and interruption capabilities. Distribution assemblies contain protective components together with necessary
33、 support structures, buswork, wiring, and electromechanical or electronic relays and meters. Exposure to fire or heat can cause insulation damage and might lead to corrosion in all of these areas. In the case of exposure of distribution assemblies to fire or heat, contact the manufacturer before any
34、 action is taken. 4.2 Motor Control Equipment Motor circuits include motor control devices (motor starters and contactors, for example) along with overcurrent-protection components, such as overload relays, circuit breakers, and fuses that are often assembled into motor control panels and motor cont
35、rol centers or individual enclosures. Motor control centers contain both control and protective components, as well as support structures, buswork, and wiring. The protective components are critical to the safe operation of motor circuits. Their ability to protect these circuits is adversely affecte
36、d by exposure to fire or heat and the potential reduction in the integrity of electrical equipment due to heat degradation of materials, residue from burning materials, or moisture. For molded-case circuit breakers, such exposure can affect the overall operation of the mechanism through contaminates
37、, through the presence of foreign particles, and through loss of lubrication. The condition of the contacts can be affected, and the dielectric insulation capabilities of internal materials can be reduced. Further, some molded-case circuit breakers are equipped with electronic trip units, and the fu
38、nctioning of these trip units can be impaired. Fire or heat can affect the fuse tube and the filler material of fuses and will degrade the insulation and interruption capabilities. Corrosion, loss of lubrication, and insulation quality can also be expected in contactors and starters. Solid-state mot
39、or controllers, adjustable speed drives, and those electromechanical contactors or starters with integral electronic circuitry will be more severely affected by fire or heat. Page 6 2016 National Electrical Manufacturers Association 4.2.1 Adjustable Speed Drives Adjustable speed drives contain elect
40、ronic components and might contain transformers or other electrical devices that could be affected by exposure to fire or heat. See section 4.11 for information on equipment with electronic components. For other components of an adjustable speed drive, the ability to refurbish those components will
41、depend on the type of component involved and the extent of the damage. The manufacturer of the drive must be consulted before any attempt to refurbish the equipment. 4.2.2 Motor Control Centers Motor control centers contain many different components, including fuses, circuit breakers, controllers, o
42、verload relays, adjustable speed drives, and components such as buswork, insulators, and enclosures. Many of these components are covered in other parts of this document, which should be referenced for additional information on those components. For the buswork and structural assembly, exposure to f
43、ire or heat can cause insulation damage and lead to corrosion. For these assemblies, contact the manufacturer before action is taken. 4.3 Power Equipment Power equipment involves low- or medium-voltage protective devices within an overall switchgear assembly. The assembly may also contain cabling, b
44、uswork with appropriate insulators, current transformers (refer to 4.4), electromechanical or electronic relays, and metering. Reliable operation of the protective devices is vital to system safety. These devices can be adversely affected by fire or heat. In the case of low-voltage power circuit bre
45、akers and medium-voltage power circuit breakers and switches, the operation of the mechanism can be impaired by the presence of carbon particles, or debris removal of lubricants and potential corrosion. The dielectric properties of insulation materials and insulators will degrade and, for air circui
46、t breakers, the condition of the contacts can be affected. Further, low-voltage power circuit breakers usually incorporate electronic trip units; the functioning of these units will be impaired. Similarly, the functionality of electromechanical or electronic protective relays and meters can be impai
47、red. See section 4.11 for additional information on electronic components. Fire or heat can affect the fuse tube and the filler material of fuses and will degrade the insulation and interruption capabilities. Low- and medium-voltage power circuit breakers may be designed to be maintained by replacin
48、g contacts in air circuit breakers. Therefore, it might be possible to reuse such circuit breakers, provided the refurbishing is performed in close consultation with the manufacturer. This includes cleaning and restoration techniques, lubrication advice, and thorough testing before the reapplication
49、 of power. Discard and replace the electronic trip units of low-voltage power circuit breakers and electronic protective relays and meters in any power equipment. Replace fusible units of fused equipment. The remainder of the apparatus might be suitable for refurbishing in close consultation with the manufacturer. Medium-voltage power circuit breakers using vacuum interrupters can become contaminated with foreign material that becomes lodged in the bellows of the device, impeding contact movement, and vacuum integrity. The manufacturer must be consulted. In a
