800amp main switch

[mazo]

hi,folks
i need some help
i have a 800amp main incomming over current switch with a bolt on earth leakage current relay,that seem to be tripping in bad weather ie when lightning is around,the site has 12 other sub boards none of which have the same device.
my question is does anyone else think it trips due to lightning feeding back up the system via earth .
the site has 2 very high lighting towers that may be conducting said unwanted voltage.
thanks guys.
mazo

 

[Darkwood]

whats its rating whats it set at have you done a rcd ramp test yet, and yes lighting can cause nuisance tripping but not regular as you suggest unless something local is acting like a lightning rod.

 

[ryanryan]

is this the only earth leakage current device in the system? What other sub supplies are down streanm?

 

[_ch_]

not made by merlin gerin by any chance is it?