On Sunday, March 11, 2018 at 10:41:15 PM UTC-4, wrote:
A friend of mine has a 120volt string of lights above his swimming pool. There is one 15 amp circuit for both the lighting and the pump motor circuit. This circuit is not protected by a GFCI outlet. The lights however are high enough so that no one can ever reach up and grab them while in the pool.. We have had discussions about installing a GFCI on the pool circuit but as of the end of last Summer's swimming season it had not been done. One day last Summer I observed his kids in the pool shooting water blaster pistols in the air. Alarmed I quickly killed power to the lights. Naturally my concern was that someone in the pool shooting water up at the lights could be electrocuted. This brought about an interesting hypothetical discussion. What if the pool lighting circuit were connected through an isolation transformer. In theory then you should be able to grab each side of the secondary without being shocked right? I can't see how the motor could fail and become a shock hazard so I was more concerned about the lights.

In any event I'm going to install a GFCI on his pool circuit for him before the start of swimming season which will be coming up in a couple of months. Thanks, Lenny

I've heard about how the inductive spark at the run start switch on some of these motors can cause GFCI's to randomly trip out and sometimes they are even destroyed by this. And I know also that with this guy if it starts to become a constant problem the GFCI will simply be replaced with a standard duplex receptacle. So I have to ask if on the off hand chance the motor wiring shorts to ground, and if the motor frame is properly grounded in theory there would be no chance that anyone in the pool would be affected by this....right? Lenny