Why did 60 Amp breaker pop

[Kenewber]

New member and DIY. I have a 60 AMP breaker going to a sub panel for a workshop. Two months ago I bought an electric car and a 40 AMP charger that I wired a 50 AMP breaker to my sub panel.

I charge from midnight to 7 am and everything has been fine for 2 months. Last night the main 60 AMP breaker popped several times after resetting it but the 50 AMP which is directly wired to the charger did not.

My charger allows me to adjust the output and I lowered it from 40 to 30 amps and it popped again. I then lowered it to 20 AMPS and it did not pop again.

Can anyone give me a clue as to why the 60 AMP breaker popped. The only thing running on the sub panel was the charger.

Thanks very much for any help. Ken.

 

[James]

I would change the old 60A breaker for a new one, if the problem persists then you have a fault that needs investigating, do not keep resetting it.
if the problem goes away then it is reasonable to assume the breaker was faulty.

 

[nicebutdim]

Is anything else supplied from the sub-panel?

 

[Kenewber]

I would change the old 60A breaker for a new one, if the problem persists then you have a fault that needs investigating, do not keep resetting it.
if the problem goes away then it is reasonable to assume the breaker was faulty.

Thanks James

 

[Kenewber]

Is anything else supplied from the sub-panel?

Yes, I have a worshop but all tools and lights were off. I even turned the new breakers off of everything except the charger and it still popped.

 

[ipf]

Thanks James

Aye, might work, just like that..........buzz just mentioned Tommy Cooper.

 

[pc1966]

Yes, I have a worshop but all tools and lights were off. I even turned the new breakers off of everything except the charger and it still popped.

That brings it down to one (or worst case more) of:

• The 60A breaker is faulty
• The cable run has a fault
• The charger has a fault

Altering the charge setting appears to stop it, so cable is less likely, and I suspect a replacement breaker is the cheapest test to rule that out before you consider the expensive case of a faulty charger.

Just to check this is over current only simple breaker, not a GFCI/RCBO unit?

 

[Kenewber]

That brings it down to one (or worst case more) of:

• The 60A breaker is faulty
• The cable run has a fault
• The charger has a fault

Altering the charge setting appears to stop it, so cable is less likely, and I suspect a replacement breaker is the cheapest test to rule that out before you consider the expensive case of a faulty charger.

Just to check this is over current only simple breaker, not a GFCI/RCBO unit?

Thanks very much for your reply. I installed
a new breaker and it appears to have fixed the problem since I charged at 40 amps last night with no problem.