How to stop current originating from common ground wire?

Question

A building has all the apartments' electric panels connected to a common ground wire.
Theoretical situation:

one of the building's electric panels has its differential circuit breaker broken
it also has a broken appliance that is permanently sending current to the ground wire

Therefore, the building's common ground wire has current flowing permanently. How can an apartment owner stop current from getting in his apartment through the common ground wire but allow current to flow out?

longneck · Answer

There should be another breaker upstream of the broken breaker.

Edward Kirton · Answer

Sounds like an unsafe situation.  To find the offending circuit, monitor the ground while opening/closing each breaker.

Ed Beal · Answer

With a 3 wire system the only way I would know to find the problem would to add an impeadance (resistor) in each apartments ground and measure the voltage. The only way to prevent the problem is to ass a rcd to each apartments supply and when the current on their ground raises to 50 ma it will trip the offending apartments breaker (I believe RCD breakers are set at 50).

Answered by Ed Beal on May 27, 2021

How to stop current originating from common ground wire?

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