On Tuesday, 24 July 2018 18:32:23 UTC+1, wrote:
OK - let's cut to the chase:

GFCI devices are designed to save lives under specific conditions. Under those same conditions, they can be inconvenient. That is a given.

What they do: They detect current flowing from the hot line, and not returning via the neutral line. If they detect this condition of more than a very, very few MA, they trip. Meaning that they WILL NOT protect anyone deliberately inserting themselves into a circuit. This despite sincere and touching wishes otherwise.

Some devices will trip a GFCI pretty much most of the time. However, that this happens DOES NOT make the GFCI device faulty. It makes the device faulty. What the device is doing is getting current from the hot side and sending it somewhere else but the neutral.

One should not (in some cases, cannot) cascade GFCI devices. Often this will cause false-trips, especially with motors.

A GFCI is also an ultra-fast circuit breaker. Meaning that older motors that commonly will not trip a regular breaker will often trip a GFCI, yet not be defective - this due to the momentary turn-on surge.

If a properly installed, properly functioning GFCI device is tripping - it is for a reason. As it is a life-safety device, the point of all this is not to defeat it, but to correct the reason for the tripping.

Any other response is stupid.
Any other advice is blather.

Peter Wieck
Melrose Park, PA

unfortunately that's incorrect on several points.