NEMA GD 1-2016 Evaluating Water-Damaged Electrical Equipment.pdf

1、 Evaluating Water-Damaged Electrical Equipment www.nema.org 2016 National Electrical Manufacturers Association Page 1 1 USE OF THIS PUBLICATION This publication serves as a guide that represents the consensus of NEMA member companies and is not intended to override the recommendations of the specifi

2、c equipment manufacturer. These guidelines provide information on how to evaluate electrical equipment that has been exposed to water through flooding, fire-fighting activities, hurricanes, and other events involving large quantities of water. It is designed for use by suppliers, installers, inspect

3、ors, and 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 water can be extremely

4、hazardous if reenergized without performing a proper evaluation and taking necessary actions. Reductions in the integrity of electrical equipment due to moisture can affect the ability of the equipment to perform its intended function. Damage to electrical equipment can also result from flood waters

5、 contaminated with chemicals, sewage, oil, and other debris, which will affect the integrity and performance of the equipment. Ocean water and salt spray can be particularly damaging due to the corrosive and conductive nature of the saltwater residue. Distributors of electrical equipment should not

6、supply any inventory that has been subjected to water damage. This can lead to the continued use of damaged equipment, creating a hazard to individuals or property. 2 CONTACT THE MANUFACTURER Working knowledge of electrical systems and the equipment in question is required to evaluate damage due to

7、contact with water. The original manufacturer of the equipment should be contacted if any questions arise or specific recommendations are needed. In many cases, a replacement will be necessary. After consultation with the manufacturer, some larger types of electrical equipment may be reconditioned b

8、y properly trained personnel. The potential to recondition the equipment may vary with the nature of the electrical function, the degree of flooding, the age of the equipment, and the length of time the equipment was exposed to water. Attempts to recondition equipment without consulting the manufact

9、urer can result in additional hazards due to the use of improper cleaning agents, which can further damage the equipment (see National Electrical CodeNEC section 110.11, Informational Note No. 2) or due to improper reconditioning techniques. NEMA member companies are committed to safety. For specifi

10、c contacts within these manufacturing firms, call or write: National Electrical Manufacturers Association 1300 North 17th Street, Suite 900 Rosslyn, Virginia 22209 Telephone: (703) 841-3236 Fax: (703) 841-3336 ATTN: Vince Baclawski email: vin_baclawskinema.org Page 2 2016 National Electrical Manufac

11、turers Association 3 ELECTRICAL EQUIPMENT REPLACEMENT/RECONDITIONING REQUIREMENTS The table shown below provides the requirements and recommendations associated with various categories of electrical equipment that have been subjected to water damage. Where it is shown that the equipment “may be reco

12、nditioned,” it is critical that the manufacturer of the equipment be contacted for specific guidance. Equipment Replace equipment May be reconditioned (contact the manufacturer) Additional standards reference (if available) ELECTRICAL DISTRIBUTION EQUIPMENT (refer to 4.1) Molded-case circuit breaker

13、s X Low-voltage fuses X Switches X NEMA KS 3-2010 Guidelines for Inspection and Preventive Maintenance of Switches Used in Commercial and Industrial Applications Busway (Mylar wrapped bars) X NEMA BU 1.1-2000 General Instructions for Handling, Installation, Operation, and Maintenance of Busway Rated

14、 600 Volts or Less, par. 3.4.4, 9.2.4.2 Busway (powder-coated bars) XPanelboards X NEMA PB 1.1-2013 General Instructions for Proper Installation, Operation, and Maintenance of Panelboards Rated 600 Volts or Less, par. 10.3, 10.8, 10.8.3, 10.8.4, 10.9 Switchboards X NEMA PB 2.1-2013 General Instructi

15、ons for Proper Handling, Installation, Operation and Maintenance of Deadfront Distribution Switchboards Rated 600 Volts or Less, par. 9.1, 9.8, 9.8.3, 9.8.4, 9.9 MOTOR CONTROL EQUIPMENT (refer to 4.2) Adjustable speed drives X Components containing semiconductors and transistors X Electronically con

16、trolled and solid-state contactors and starters X Overload relays X Manual and magnetic controllers XMotor control centers (see 4.2.2) 2016 National Electrical Manufacturers Association Page 3 Equipment Replace equipment May be reconditioned (contact the manufacturer) Additional standards reference

17、(if available) POWER EQUIPMENT (refer to 4.3) Electronic trip units of LV power circuit breakers X High-voltage circuit breakers (AC) X Low-voltage power circuit breakers Electromechanical protective relays, meters, and current transformers (see section 4.11 for devices that contain electronic compo

18、nents) X Electronic protective relays, meters, and current transformers (see section 4.11) X Low-voltage 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 Liqui

19、d-filled transformers X (Analysis of the insulating medium is required for evaluation of this equipment.) 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, E

20、lectrical Metallic 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, Covers and Box Supports Conduit and tubing X Page 4 2016 National Electrical Manufacture

21、rs Association Equipment Replace Equipment May be Reconditioned (Contact the manufacturer.) Additional Standards Reference (if available) WIRE, CABLE, AND FLEXIBLE CORDS (refer to 4.6) Wire or cable listed for dry locations (such as NM-B) X Wire or cable that is suitable for wet locations (Provided

22、the ends of the wire or cable have not been exposed to water, and the wire is not damaged.) X AFCIs, GFCIs, SURGE PROTECTIVE DEVICES AND WIRING DEVICES (refer to 4.7) Arc-fault circuit interrupters (AFCI) and ground-fault circuit interrupters (GFCI) X Surge-protective devices (transient voltage surg

23、e suppressors, surge arresters, lightning arresters) X Wiring devices (switches, receptacles, dimmers, etc.) X OTHER DEVICES Batteries (refer to 4.12) X Cable tray (refer to 4.8) X (Replace damaged labels.) Fire pump controllers X NEMA ICS 15-2011 Instructions for the Handling, Installation, Operati

24、on, and Maintenance of Electric Fire Pump Controllers Rated Not More Than 600V Luminaires (lighting fixtures), ballasts, and LED drivers (refer to 4.9) X Motors (refer to 4.10) X ANSI/IEEE 43-2013, A2 and A3, ANSI/EASA AR100 Signaling, protection, and communications systems (refer to 4.11) X Uninter

25、ruptible power supply (UPS) X 2016 National Electrical Manufacturers Association Page 5 4 THE HAZARDS ASSOCIATED WITH WATER-DAMAGED ELECTRICAL EQUIPMENT 4.1 Electrical Distribution Equipment Electrical distribution equipment usually involves switches and low-voltage protective components such as mol

26、ded-case circuit breakers and fuses within assemblies such as enclosures, panelboards, and switchboards. These assemblies can be connected to electrical distribution systems using various wiring methods. The protective components are critical to the safe operation of distribution circuits. Their abi

27、lity to protect these circuits is adversely affected by exposure to water and to the minerals, contaminants, and particles, which may be present in the water. In molded-case circuit breakers and switches, such exposure can affect the overall operation of the mechanism through corrosion, through the

28、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 functioning of t

29、hese trip units can be impaired. Water may affect the filler material of fuses and will degrade the insulation and interruption capabilities. Distribution assemblies contain protective components together with the necessary support structures, buswork, wiring, electromechanical, or electronic relays

30、, and meters. Exposure to water can cause corrosion and insulation damage to all of these areas. In the case of exposure of distribution assemblies to water, contact the manufacturer before further action is taken. 4.2 Motor Control Equipment Motor circuits include motor control devices such as moto

31、r starters and contactors, whichtogether with overcurrent protection components such as overload relays, circuit breakers, and fusesare often assembled into motor control panels and motor control centers, as well as individual enclosures. Motor control centers contain both control and protective com

32、ponents, together with support structures, buswork, and wiring. The protective components are critical to the safe operation of motor circuits, and their ability to protect these circuits is adversely affected by exposure to water and to the minerals, contaminants, and particles that may be present

33、in the water. For molded-case circuit breakers, such exposure can affect the overall operation of the mechanism through corrosion, 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

34、internal materials can be reduced. Further, some molded-case circuit breakers are equipped with electronic trip units, and the functioning of these trip units can be impaired. Water may affect the filler material of fuses and can degrade the insulation and interruption capabilities. Corrosion, loss

35、of lubrication, and insulation quality can also be expected in contactors and starters. Solid-state motor controllers, adjustable speed drives and those electromechanical contactors or starters with integral electronic circuitry will be more severely affected by water. 4.2.1 Adjustable Speed Drives

36、Adjustable speed drives generally contain electronic components. 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 depend on the type of component involved and the extent of the

37、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, overload relays, and adjustable speed drives, as well as compone

38、nts such as buswork, insulators, and Page 6 2016 National Electrical Manufacturers Association enclosures. Many of these components are covered in other parts of this document and should be referenced for additional information on those components. For the buswork and structural assembly, exposure t

39、o water can cause corrosion and insulation damage. For these assemblies, contact the manufacturer before further action is taken. 4.3 Power Equipment Power equipment involves low-voltage or medium-voltage protective devices within an overall switchgear assembly. The assembly may also contain cabling

40、, buswork with appropriate insulators, current transformers, electromechanical or electronic relays, and metering. Reliable operation of the protective devices is vital to system safety. These devices can be adversely affected by water. In the case of low-voltage power circuit breakers and medium-vo

41、ltage circuit breakers and switches, the operation of the mechanism can be impaired by corrosion, the presence of particles such as silt, and the removal of lubricants. The dielectric properties of insulation materials and insulators will degrade, and, for air circuit breakers, the condition of the

42、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 electronic protective relays and meters can be impaired. See section 4.11 for additional information on el

43、ectronic components. Water may affect the filler material of fuses and will degrade the insulation and interruption capabilities. Low-voltage power circuit breakers and medium-voltage breakers are designed to be maintainable with the possibility of replacing contacts in air circuit breakers. Therefo

44、re, it maybe possible to reuse such circuit breakers, provided the refurbishing is performed in close consultation with the manufacturer. This includes cleaning and drying techniques, lubrication advice, and thorough testing before the reapplication of power. However, discard and replace the electro

45、nic 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 may be suitable for refurbishing in close consultation with the manufacturer. In all cases, attention mus

46、t be paid to the thorough cleaning, drying, and testing of insulators and insulation material. The power equipment can be expected to contain additional electronic units such as solid-state relays. These units can be vital to the correct functioning of the protective device, and great care is needed

47、 in the cleaning and testing of such units. A first recommendation is to return the devices to the manufacturer. If this is not possible, the manufacturer should be consulted on the correct selection of cleaning agents that remove impurities without damaging the conformal coating. The manufacturer s

48、hall also be contacted for the specific testing required for sophisticated electronic equipment containing, for example, microprocessors. The overall power equipment assembly (switchgear) may be able to be reconditioned, provided careful steps are taken in the cleaning, drying, and testing of the eq

49、uipment before applying power. This requires input and advice from the manufacturer. An area of particular concern is the maintenance of the dielectric properties of insulation. In the field application of medium-voltage equipment, standoff insulators are subjected to a wide variety of high-voltage surges. Such insulators may need replacement. 4.4 Transformers Exposure of transformers to water can cause corrosion and insulation damage to the transformer core and winding. The ability of the transformer to perform its intended function in a safe manner can also be impai