Heat Pump blowing main breaker

[patricknola]

I am servicing an inastallation someone else did. There are two heat pumps, after they were installed they ran for about an hour when the installer noticed that one wasn't running so he checked and noticed the breaker was thrown. After trying to reset the breaker there was a spark behind the breaker(dead short) and the main breaker tripped and couldn't be reset. How can tell if the main breaker is no good or that matter how can I ever tell if a breaker has been ruined after a dead short. Any other ideas about heat pump installations would be much appreciatted. thank you, Patrick from New Orleans.

 

[petersonra]

I am servicing an inastallation someone else did. There are two heat pumps, after they were installed they ran for about an hour when the installer noticed that one wasn't running so he checked and noticed the breaker was thrown. After trying to reset the breaker there was a spark behind the breaker(dead short) and the main breaker tripped and couldn't be reset. How can tell if the main breaker is no good or that matter how can I ever tell if a breaker has been ruined after a dead short. Any other ideas about heat pump installations would be much appreciatted. thank you, Patrick from New Orleans.

A tripped CB is not supposed to be reset until after it has been determined why it tripped and the cause corrected.

Just because someone saw a "spark" does not mean there was a dead short.

If the main breaker tripped and can't be reset, maybe there is some kind of short. It is also possible that the CB failed.

Someone is going to have to investigate and find out what happened and fix it.

Probably has nothing to do with it being a heat pump.

 

[Dennis Alwon]

First off if you are a student do you have someone supervising you?

Does the main breaker reset and trip or is the handle stuck?

Very possible you are in over your head and can get hurt on this. Arc flash can be a dangerous thing so don't just go turning stuff on

 

[patricknola]

How to test a breaker

How to test a breaker

So again, my question is, how can one test a breaker to tell if it is no good?

 

[Ragin Cajun]

Considering that one must have the proper breaker overcurrent trip test equipment, quite expensive, it is simpler and cheaper to simply replace the breaker (s).

Of course, the system should be meggered, verify that all related breakers are the correct size for the application, etc.

How was Fat Tuesday?

RC

 

[patricknola]

Fat Tuesday was fantastic, the weather was beautiful and I live about 5 blocks from the French Quarter. Right now I am studying to take the state Class D licence, so I am kind of stuck studying the code book.

 

[growler]

I am servicing an inastallation someone else did. There are two heat pumps, after they were installed they ran for about an hour when the installer noticed that one wasn't running so he checked and noticed the breaker was thrown. After trying to reset the breaker there was a spark behind the breaker(dead short) and the main breaker tripped and couldn't be reset. How can tell if the main breaker is no good or that matter how can I ever tell if a breaker has been ruined after a dead short. Any other ideas about heat pump installations would be much appreciatted. thank you, Patrick from New Orleans.

So again, my question is, how can one test a breaker to tell if it is no good?

If the main breaker won't reset that makes it kind of useless. Did they give it a few minutes to cool off before trying to reset?

If there is a short you should be able to measure that with your ohm meter. Check the conductors going to the heat pump with the tripped breaker. If it shows a short then open the disconnect and see if it's still shorted. You need to know if it's the circuit or the heat pump that's bad.

While you are checking out the short the main breaker will have time to cool. You can check for voltage drop between line and load on the breaker to see if the contacts are bad.

 

[kwired]

I am servicing an inastallation someone else did. There are two heat pumps, after they were installed they ran for about an hour when the installer noticed that one wasn't running so he checked and noticed the breaker was thrown. After trying to reset the breaker there was a spark behind the breaker(dead short) and the main breaker tripped and couldn't be reset. How can tell if the main breaker is no good or that matter how can I ever tell if a breaker has been ruined after a dead short. Any other ideas about heat pump installations would be much appreciatted. thank you, Patrick from New Orleans.

When the one heat pump breaker was reset/turned on it closed into a fault. The resulting arc blast inside that breaker partially escaped out the rear of the breaker making it appear as though something happened behind the breaker.

The fault current that flowed was high enough to get into the instantaneous trip range of the main breaker which is why it tripped. For some reason the main breaker had a failure that won't let it reset. Even if it can be properly tested and refurbished, it will cost more then a replacement - so just replace it and move on, after finding the fault that caused all this to start with - it is somewhere in the branch circuit of the heat pump that was tripped to start all of this.

 

[qcroanoke]

I am servicing an inastallation someone else did. There are two heat pumps, after they were installed they ran for about an hour when the installer noticed that one wasn't running so he checked and noticed the breaker was thrown. After trying to reset the breaker there was a spark behind the breaker(dead short) and the main breaker tripped and couldn't be reset. How can tell if the main breaker is no good or that matter how can I ever tell if a breaker has been ruined after a dead short. Any other ideas about heat pump installations would be much appreciatted. thank you, Patrick from New Orleans.

Was this breaker that tripped in the panel or at the unit? In either case turn it off and all other breakers in the panel. Then try to turn on the main. If it holds turn on the breakers one at a time to see if it stays on. saving the heat pump breaker for last. If it trips it's somewhere between the panel and in the unit. then unhook the unit and try it.