GFCI Breaker Trips during Lightening Storms

[AndrewB77]

Hi All. First time poster here looking for some advice. I have been having issues with a GFCI breaker being tripped whenever we have very close lightening. Here is the current wiring configuration:
20amp GFCI at the panel. This circuit runs outside and powers the pool pump and a receptacle (covered by a weather box - approx. 4ft off the ground). Recently I added a leg from the receptacle to my shed which is about 75 feet away. I used 12/2 direct burial cable which is buried anywhere between 24"-30". Whenever we have a storm with lightening that strikes very close, it trips the circuit. This never seemed to happen before I added the leg to the shed. I have disconnected the leg to the shed to test and, ironically, we haven't had much in the way of tstorms lately! All you pro's have any advice on what could be happening? And, is there a way I could remedy this?

Thanks!!!

 

[pc1966]

Well you might have found a fix by now given it is coming up for a year, but...

Firstly it is not uncommon for RCD=GFCI to trip on surges as the rapid change in voltage results in extra current through any cable to ground capacitance.

Secondly there are no simple & absolute fixes for this, but in recent years it is common (maybe even in the regulations for USA as well) to have surge protection devices at the main incoming panel in an installation. You might find that reduces the tendency to trip, and at the very least it would reduce the risk of over-voltage damage to any electronics.