Another engineer just performed a punch list inspection with the electrical contractor for a project that we recently completed. The contractor informed him that the GFCI receptacles serving the electric water coolers, which are required to be GFCI-protected as of the 2008 NEC, were frequently tripping. The issue was allegedly resolved by installing standard receptacles in conjunction with GFCI circuit breakers. There are several things that I don't understand.
1. How common is GFCI nuisance-tripping on small refrigeration equipment and other fractional horsepower motor loads? In addition to electric water coolers, the NEC now requires GFCI protection for vending machines and many other appliances. Furthermore, all 120-volt receptacles in commercial kitchen facilities, which often contain refrigerators, ice makers, etc. - require GFCI protection. It was my understanding that older GFCI and AFCI devices were subject to nuisance tripping on these types of loads, but I thought these issues were resolved by manufacturers long ago.
2. Why would a GFCI breaker necessarily be less prone to nuisance tripping? When considering leakage current via shunt capacitance, one would think that the reverse is true. I believe SquareD recommends a maximum one-way circuit length of 200 feet for their GFCI breakers. In a scenario in which I had an electric water cooler or similar appliance located more than 200 feet from its source panelboard, what would be the best strategy to provide reliable GFCI protection?
3. Are some GFCI receptacles less prone to nuisance-tripping than others? Are there certain manufacturers that anyone can recommend (or not recommend)?
4. How likely is it that the electric water coolers are simply defective? I believe they're all brand new, in excellent condition, and installed properly.
Thanks in advance for any input provided!