DIYbanter - View Single Post

Ralph Mowery

In article ,
says...

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

An isolation transformer would be safe up to a point. If there is a
breakdown in the insulation anywhere in the circuit, one side of the
circuit becomes grounded by accident and no one notices it. Then if
someone gets on the other side of the line, he is shocked or worse.
That is one reason most circuits are grounded.