GFCI troubleshooting question

[elecmen]

Hi, Went to troubleshoot GFCI breakers tripping for no aparent reason. Heres the setup 3 20A circuits in a single EMT conduit all circuits GFCI protected by there own GFCI breaker. Saw with my own eyes that all 3 breakers tripped at the same time! I have checked all connections at the receptacles. The equipment ground is insulated so no bare copper to neutral problem. After checking all connection I put evey thing back together and 3 hrs later they tripped again. I now have made sure there is nothing plugged in to these receptacles. I will check tomorrow to see if something plugged in was the problem. Does anyone have any idea what the problem could be?

 

[ptonsparky]

Make sure the neutrals are not going to the wrong breaker or are spliced together some where.

 

[big john]

If they all trip as soon as any load is applied, it's because of crossed neutral conductors.

If they hold load but all trip simultaneously later on, check for nearby sources of radio interference: Have seen walkie-ties trip a GFCI and have heard of it caused by radio transmitters and cell phones.

 

[ActionDave]

Does anyone have any idea what the problem could be?

Like the others said, neutral/wiring problem. I know the first thing I would do is put a load on each of the circuits and see what happens.

 

[mopowr steve]

If the above responses don't satisfy your problem there may be a problem with the neutral feeding your panel the GFCIs are in or problem at service/utility.

 

[kwired]

A problem on the feeder/service side will not change the balance of hot/neutral current flowing in a properly wired circuit. It can change the voltage seen at the load as well as damage the GFCI electronics, but it will not cause unbalanced current in the CT inside the GFCI device.