# W/H trips main breaker intermittently



## McClary’s Electrical (Feb 21, 2009)

mtc701 said:


> This issue has been bugging me for a couple days. This is a apartment complex and the residents water heater keeps tripping the main breaker. The main breaker seems to trip intermittently because I can flip the w/h breaker on and it never instantly tripped the main breaker
> 
> Whats been done all ready is replacing the w/h. It needed changed anyways, was about 20 years old. Then making sure both wires going into the main breaker are secured. My next guess would be the main c/b itself (which is also probably about 20 years old). Another guy seems to think its the wiring going from the water heater to the inside c/b panel. Which I wouldnt rule out but would probably be the last thing i would change. Just curious if anyone has had this similiar issue before.


Megger the branch circuit and perform a fall of potential test on the main breaker while it's under load. Make sure the water heater is heating when you do it. Also, crouse hinds stab in mains are famous for burning the buss behind the main.


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## jhall.sparky (Jun 14, 2011)

change the main .........................


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## Jlarson (Jun 28, 2009)

mcclary's electrical said:


> Megger the branch circuit and perform a fall of potential test on the main breaker while it's under load. Make sure the water heater is heating when you do it. Also, crouse hinds stab in mains are famous for burning the buss behind the main.


Yay, testing :laughing:


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## don_resqcapt19 (Jul 18, 2010)

Why would you start with a megger and FOP and changing breakers? I would be looking at current and voltage first. How do they know that the water heater is causing the main to trip? Mayve it is just doing its job...maybe the load is such that the main should trip.


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## mtc701 (Sep 30, 2009)

mcclary's electrical said:


> Megger the branch circuit and perform a fall of potential test on the main breaker while it's under load. Make sure the water heater is heating when you do it. Also, crouse hinds stab in mains are famous for burning the buss behind the main.


I dont even own a megger and neither does the maintenance shop here. That might be what has to be done if replacing the main circuit breaker doesnt fix the issue. The ONLY reason it hasnt been done yet is because we dont have extra ones in the shop. I am just kind of watching this other guy do his thing :laughing: I guess he actually all ready ran a temporary wire from the w/h to the cb instead of going to Lowes to pick up a Square D 30 amp breaker.

Tommorow when i find out the cb tripped again I'll just start driving to Lowes...


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## jhall.sparky (Jun 14, 2011)

don_resqcapt19 said:


> Why would you start with a megger and FOP and changing breakers? I would be looking at current and voltage first. How do they know that the water heater is causing the main to trip? Mayve it is just doing its job...maybe the load is such that the main should trip.


guy your missing a few things here and ill just tell you its NOT what you think.............................. you wanna check out a few more threads then check back?


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## don_resqcapt19 (Jul 18, 2010)

jhall.sparky said:


> ... you wanna check out a few more threads then check back?


not really


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## mrmike (Dec 10, 2010)

don_resqcapt19 said:


> Why would you start with a megger and FOP and changing breakers? I would be looking at current and voltage first. How do they know that the water heater is causing the main to trip? Mayve it is just doing its job...maybe the load is such that the main should trip.


 
This is the right step-not wandering around assuming things !! You already changed the WH to no avail so now you want change the main breaker without knowing for sure. Would you want a mechanic do that to your car? 
I don't think you mentioned the WH breaker tripping. This is a clue to possibly the Main Breaker overloading & tripping with the extra load of the WH.
You need to watch the load at peak times, or talk to the residints, about what they are using or maybe something added like a new A/C unit.


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## Shockdoc (Mar 4, 2010)

Are you the Super ?


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## mtc701 (Sep 30, 2009)

I guess it did happen to be the wire from the w/h to the breaker. The ohm-meter was reading short to ground. But it wasnt reading that the entire time thus the intermittent cb tripping. Breaker also replaced for good measure, no further cb tripping.


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