Earth leakage trip during lightning

[govender1]

Is it normal for a domestic 220V 30mA earthleakage unit to trip during a lightning storm? I have experienced problem this on numerous occasions.

 

[Bung]

It is only 'normal' if you have an insulation problem somewhere in your system - It sounds like an earth potential rise problem. Is your area PME or MEN?

 

[deltawye]

Are you refering to a GFCI device when you say earth leakage unit?[\b]

 

[busbar]

The complaint can show up where the LV circuit is served from a Grounded-Wye Primary/Grounded-Wye Secondary distribution transformer. Steep-rise-time zero-sequence currents are reflected in both sides of the transformer's common metallic hi- and low-side connection. IIRC, the high- and low-side currents in grounding-electrode conductors may be [not necessarily equally] divided between the two.

For lightning hits, 30 mA is a relatively low value. Isolation of the high-side neutral-to-ground connection may cure the problem, but for graded-primary insulation {or singe-bushing transformers,} the cure may be worse than the symptom.