I have two questions pertaining to the same piece of equipment. First, I have an old (30+)FPE 1200A 120/208v switchboard in an office complex. I am guessing by the rodents inside that it has not been services in quite a while. I am also guessing that the main breaker has never been exercised, lubricated or even tested to see if it would open in a fault event. What is the best way to test the breaker(s)? Secondly I think this switchboard is overloaded, what is the advise for performing a load calculation?
Testing a Main Breaker
- Thread starter ribender
- Start date
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- Location
- Massachusetts
Re: Testing a Main Breaker
We often rent recording meters to check the load and or voltage on a service.
Typically we will monitor it for a week but you need to know if your larger electric loads are in the winter or summer.
We also hire a testing company that can load test breakers on site if we have doubts about a breaker.
We often rent recording meters to check the load and or voltage on a service.
Typically we will monitor it for a week but you need to know if your larger electric loads are in the winter or summer.
We also hire a testing company that can load test breakers on site if we have doubts about a breaker.
brian john
Senior Member
- Location
- Leesburg, VA
Re: Testing a Main Breaker
If the circuit breaker can be removed from service the following test ate performed.
Megger/high potential testing Pole to pole, line to load with the circuit breaker open and depending on the type of circuit breaker pole to ground.
Ductor/DLRO/micro-ohm meter, measuring the contact resistance of the power poles.
Primary injection testing- On molded case circuit breakers you perform a high current test at pick up for instantaneous and at 300 percent of the circuit breaker rating for long time. assuming the circuit breaker has these features. This requires owning a high current test set.
If the circuit breaker can be removed from service the following test ate performed.
Megger/high potential testing Pole to pole, line to load with the circuit breaker open and depending on the type of circuit breaker pole to ground.
Ductor/DLRO/micro-ohm meter, measuring the contact resistance of the power poles.
Primary injection testing- On molded case circuit breakers you perform a high current test at pick up for instantaneous and at 300 percent of the circuit breaker rating for long time. assuming the circuit breaker has these features. This requires owning a high current test set.
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