So back to the hot tub installation...

It is imperative to ensure that it is impossible to touch both ungrounded poles in any 240 V installation. GFCI cannot protect against this.

I think this is a bit different from a 120 V installation with GFCI.
In 120 V, I can get a nasty shock between ungrounded and grounded conductors. However, enough current might leak through my feet to the earth and trip the GFCI.

With 240 V, if the amounts leaking to earth from each ungrounded conductor are equal, they cancel each other locally and don't trip the GFCI.

Envision the cable being cut and submerged into a mud puddle.

The 120 V GFCI will probably trip as current follows earth or ground rather than neutral.
The 240 V GFCI possibly won't trip.


[This message has been edited by Dspark (edited 05-09-2001).]