We called out the contractor who did our crawlspace encapsulation because the GFCI receptacle that serves the crawlspace loads (dehumidifier, sump pump, and two humidistat controlled fans) trips occasionally - I think this happens during the rainy season when humidity is high during the rainy season, but since the battery backed pump sounds an alarm when it loses power we disconnected one of the fans which stopped the tripping.
The contractor is putting forth the theory that since it is a 15 A circuit (14 AWG NM cable and a 15 A breaker) there may be an overload if all of the devices startup at about the same time and this may cause the GFCI to trip. That makes no sense to me because I don't think GFCIs work that way - but he is adamant that he has seen this happen.
I'm thinking that we must be seeing some leakage from one of the fans or the humidistat - but I don't want to be going off half-cocked, my years as an electrician are long past and I never did residential work.
Could startup loads from the motors down there be the cause of the GFCI tripping?