Re: Security sytem on GFI outlet ?
Since a standard secutity alarm system is not considered a "Life Safety" system, there wouldn't be any NFPA codes, that I am aware of, that would address this system.
The likelyhood of the GFCI recptacle tripping with this transformer is very remote.
If the receptacle is on a GFCI circuit breaker with other loads, then you take your chances that something else doesn't trip the breaker.