Electrical Distribution Equipment
Electrical distribution equipment usually involves switches and low-voltage protective components
such as molded 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 ability to
protect these circuits is adversely affected by exposure to water and to the minerals 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 presence of
foreign particles, and through removal of lubricants. 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 these
trip units might be impaired. For fuses, the water may affect the filler material. A damaged filler
material will degrade the insulation and interruption capabilities.
Distribution assemblies contain protective components together with the necessary support
structures, buswork, wiring, electromechanical or electronic relays 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, the manufacturer should be contacted before further action is
taken.
Items Which May Possibly Be Reconditioned by Trained Personnel in Consultation with
Manufacturer:
- Enclosed switches—reference NEMA Standards Publication KS 1-2001, Enclosed and Miscellaneous Distribution Equipment Switches (600 Volts Maximum), para 5.1, 5.1.2
- Busway—reference NEMA Standards Publication BU 1.1-2000, General Instructions for Handling, Installation, Operation, and Maintenance of Busway Rated 600 Volts or Less, para 3.4.4, 9.2.4.2
- Panelboards—reference Standards Publication ANSI/NEMA PB 1.1-2002, General Instructions for Proper Installation, Operation, and Maintenance of Panelboards Rated 600 Volts or Less, para. 10.3, 10.8.3, 10.8.4
- Switchboards—reference Standards Publication ANSI/NEMA PB 2.1-2002, General Instructions for Proper Handling, Installation, Operation and Maintenance of Deadfront Distribution Switchboards Rated 600 Volts or Less, para. 11.3.1.3, 11.10
- Fire Pump Controllers—reference NEMA Standards Publication ICS 15-1999 (R2004), Instructions for the Handling, Installation, Operation, and Maintenance of Electric Fire Pump Controllers Rated Not More Than 600 V
Motor Circuits
Motor circuits include motor control devices such as motor starters and contactors, together with overcurrent protection components such as overload relays, circuit breakers, and fuses often assembled into motor control panels and motor control centers as well as individual enclosures.
Motor control centers contain both control and protective components 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 and particles which may be present 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 removal of lubricants.
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 these trip units might be impaired. For fuses, the water may affect the filler material. A damaged filler material will degrade the insulation and interruption capabilities.
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