Users Warned About Restarting Waterlogged Electrical Equipment
Electrical equipment that has contacted water or been submerged usually must be replaced, although larger equipment may be able to be reconditioned by trained factory service personnel, Schneider Electric advises.
With residents and business owners still cleaning up from extensive flooding caused by Hurricane Irene in New York, New Jersey, and Vermont, experts are warning them that some types of waterlogged electrical equipment cannot safely be reused. Schneider Electric, a global specialist in energy management, urged businesses to take precautions both before and after the storm raced up the East Coast.
Electrical equipment that has been submerged or has contacted water must be replaced, although there are exceptions to this rule for larger equipment, which may be able to be reconditioned by trained factory service personnel, according to the company's news release. Equipment that could be reconditioned includes:
- Switchboard enclosures and certain bus structures
- Switchgear
- Low-voltage power circuit breakers
- Medium-voltage circuit breakers
- Low-voltage bolted-pressure switches
- Medium-voltage switches
- Motor control center enclosures and bus structure
- Panelboard and load center enclosures
- Liquid-filled power transformers
- Cast-resin transformers
- Busway: epoxy coated bars
"Attempting to dry out the equipment (in many cases) leaves portions of the current-carrying parts with damp or wet surfaces," according to the release. "These surfaces may be in contact with insulators or other materials that prevent them from being properly dried out and cleaned of debris. Residual debris or wet surfaces may result in a loss of dielectric spacing within the equipment, and could present a hazard upon re-energization."
Equipment that must be replaced:
- Miniature and molded case circuit breakers
- Molded case switches
- Multi-metering equipment
- Safety switches (AC and DC)
- Load centers or panelboard interiors
- Dry-type transformers
- Busway: mylar wrapped bars
- Solid state components
- Programmable logic controllers
- Fuses
- Electromechanical relays, contactors, starters, push buttons, limit switches, and other input logic and output controls
- Solid state motor starters
- Adjustable speed drives
- Motor control center components
Some equipment has field-replaceable interior components: a load center or panelboard type of product where the entire assembly can be removed and replaced as a unit, for example. It is possible the enclosures can be reused if they have not been subjected to physical damage and have been properly cleaned.
"Do not apply cleaning agents, particularly petroleum-based cleaners, to the current-carrying portions of electrical equipment to remove foreign debris, residues and other substances. Some cleaning and lubricating compounds can cause deterioration of the non-metallic insulating or structural portions of the equipment. Do not use abrasives such as sandpaper or steel wool to clean current-carrying parts of the equipment. These materials may remove plating or other conductive surfaces from the parts, which could result in a hazard when the equipment is re-energized," the company advises.
Useful references include: NEMA Standard AB 4-2003, Guidelines for Inspection and Preventive Maintenance of Molded Case Circuit Breakers Used in Commercial and Industrial Applications; NEMA Standard BU 1.1-2000, General Instructions for Proper Handling, Installation, Operation, and Maintenance of Busway Rated 600 Volts or Less; NEMA Standard PB 1.1-2002, General Instructions for Proper Installation, Operation, and Maintenance of Panelboards Rated 600 Volts or Less; NEMA Standard PB 2.1-2002, General Instructions for Proper Handling, Installation, Operation, and Maintenance of Deadfront Distribution Switchboards Rated 600 Volts or Less; and NEMA Standard ICS 1.1-2003, Industrial Control and Systems: Safety Guidelines for the Application, Installation, and Maintenance of Solid State Controls.