# ABB Breaker



## Evan88 (Aug 25, 2010)

I was doing some trouble shooting on a chiller yesterday and ran into this problem. Breaker was tripping so i check the amperage. The amperage draw was different on each side on the breaker. What could cause this?


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## oldtimer (Jun 10, 2010)

Evan88 said:


> I was doing some trouble shooting on a chiller yesterday and ran into this problem. Breaker was tripping so i check the amperage. The amperage draw was different on each side on the breaker. What could cause this?


 What is the breaker feeding?


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## JRaef (Mar 23, 2009)

Evan88 said:


> I was doing some trouble shooting on a chiller yesterday and ran into this problem. Breaker was tripping so i check the amperage. The amperage draw was different on each side on the breaker. What could cause this?


You mean that you clamped on at the line side and the load side _at the same time_ and got different readings? Because if you clamped on the line, then clamped on the load, the current draw may have changed in that few seconds.

If it really is different, how different? Everyplace where there is a connection represents some small amount of resistance. So the line lugs, the internal component connections, the contacts themselves, the thermal current sensors , the magnetic current sensors and the load lugs of your breaker will all have a small amount of voltage drop across them, so the current will be ever so slightly different from one side to the other. But if you have 2 or 3 A differential, then you probably have a problem with the contacts in the breaker. A thermal scan would show that as well.


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## albert (Mar 17, 2011)

You could measure for voltage diffrential across the breaker. Line to load should be zero. Any voltage means the breaker has resistance. Amps in would equal amps out unless a seperate return path is present. Any load in serries has the same current. The bad breaker being in serries with the load. Only parallel circuits have different amperages. 


Regards,

Albert


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