The following came out of “Electrical Currents” a newsletter for electrical contractors and the electrical industry in Washington.
You know what struck me about this? This kind of thing doesn’t happen with solar. Our equipment is required by Underwriters Laboratories to never turn on if the grid isn’t present.
Generator Backfeed Near-Miss: Last month, a Potelco line crew working in Pierce County experienced a dangerous near-miss. A backfeed from a customer’s temporary generator had energized the utility’s wiring. Luckily, the crew discovered that power was present and was not injured.
A similar situation occurred in Yakima a few years ago when a new service panel was energized during construction by a temporary generator. While working on the utility system, a meter technician was injured. The service conductors were energized by backfed power from an improperly installed generator.
With the coming storm season, anyone doing electrical work needs to be aware of the potential for a circuit that is de-energized to suddenly become energized. Always verify that a circuit is isolated from it’s source of supply and from any potential sources of backfeed before working on it.
Installing a generator system is potentially one of the most dangerous types of electrical installations to your family, employees, and the utility’s line workers. Legally and safely installing a generator system is very specialized work that requires expertise and experience. Prior to making a generator system purchase or installing a generator system, review the special edition Electrical Currents – October 2007.
L&I strongly encourages anyone interested in having a generator system installed at their home or business to work with a properly licensed electrical contractor. Before beginning the work, get written bids from two or three electrical contractors and verify that each has significant experience installing generator systems. Ask for references. Then make certain your contractor gets an electrical permit and has an inspection to verify that the work was done correctly and safely.