tool to test circuit breakers?

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JJWalecka

JJWalecka

Senior Member
Location
New England
Is there a tool or technique to make sure a circuit breaker is working properly?

I have the tool used to check a GFCI, to make sure it trips at the proper setting.

Some contractors have old circuit breakers stocked on their shelves. I was wondering if installing them would be a liability and or safety issue.

Justin
 
480sparky

480sparky

Senior Member
Location
Iowegia
Most run-of-the-mill breakers are so inexpensive, it's cheaper to just buy a new one rather than waste the time to test an old one.
 
GeorgeB

GeorgeB

ElectroHydraulics engineer (retired)
Location
Greenville SC
Occupation
Retired
LarryFine said:
You don't need that expensive stuff. All you need is a Variac and a clamp-on ammeter. :cool:
Click to expand...
Rather than overload a directly connected Variac, I used to use a 6.3V 50A filament transformer between the 2. With the demise of the FETs in heated glass bottles (BIG GRIN), these are not as prevalent as they once were.
 
zog

zog

Senior Member
Location
Charlotte, NC
JJWalecka said:
Is there a tool or technique to make sure a circuit breaker is working properly?
Click to expand...

What type of breakers? They will all require different types of test equipment, we have millions of dollors invested in CB test equipment. A primary injection test set, which is the most important piece of equipment, runs in the $20k-$50k range.

JJWalecka said:
Some contractors have old circuit breakers stocked on their shelves. I was wondering if installing them would be a liability and or safety issue.

Justin
Click to expand...

Unless they are fully tested with the proper equipment (calibrated) there is no way to know if they will work or not and can be a huge liability.
 
Rewire

Rewire

Senior Member
Location
Lake of the Ozarks
JJWalecka said:
Is there a tool or technique to make sure a circuit breaker is working properly?

I have the tool used to check a GFCI, to make sure it trips at the proper setting.

Some contractors have old circuit breakers stocked on their shelves. I was wondering if installing them would be a liability and or safety issue.

Justin
Click to expand...

Are you talking old or used? We have breakers left over from jobs that will set on the shelf until we find a use.
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
zog said:
What type of breakers? They will all require different types of test equipment, we have millions of dollors invested in CB test equipment. A primary injection test set, which is the most important piece of equipment, runs in the $20k-$50k range.
Click to expand...

I bet we are talking 1, 2 and 3 pole 15 through 100 amp molded case circuit breakers used for branch circuit and small feeder protection.


Unless they are fully tested with the proper equipment (calibrated) there is no way to know if they will work or not and can be a huge liability.
Click to expand...

From a guy that makes his living testing breakers. :grin:
 
JJWalecka

JJWalecka

Senior Member
Location
New England
Iwire "I bet we are talking 1, 2 and 3 pole 15 through 100 amp molded case circuit breakers used for branch circuit and small feeder protection."

Yep

Rewire "Are you talking old or used? We have breakers left over from jobs that will set on the shelf until we find a use."

A used circuit breaker a few years old would presumably be ok? I know of a few contractors that might remove a breaker and then install it on another project.

To insure safety, I was wondering if the breaker could be tested before installation. I have never seen this done.
Seemed like a liability issue if the used breaker wasn?t tested. For that fact, how would you document that the breaker passed testing?
 
zog

zog

Senior Member
Location
Charlotte, NC
JJWalecka said:
Rewire "Are you talking old or used? We have breakers left over from jobs that will set on the shelf until we find a use."
Click to expand...
As long as they are still under waranty I don't see a problem with that.

JJWalecka said:
A used circuit breaker a few years old would presumably be ok? I know of a few contractors that might remove a breaker and then install it on another project.
Click to expand...
Yikes!
JJWalecka said:
To insure safety, I was wondering if the breaker could be tested before installation. I have never seen this done.
Click to expand...
Sure it can, there are many companies that do nothing else but testing of breakers, transformers, etc...
JJWalecka said:
Seemed like a liability issue if the used breaker wasn?t tested. For that fact, how would you document that the breaker passed testing?
Click to expand...
Yes it is, you just fill out a test report.
 
brian john

brian john

Senior Member
Location
Leesburg, VA
A small high current test set for testing CBs (20-100 amp CBs) runs around 8,000.00 and they go up from there, larger frame CBs will need to be ductored/DLRO'd another 3-4K, then a megger 300.00 and up.

Then the knowledge to utilize the equipment and understand the results.
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
brian john said:
We recently tested 6 - 225 amp CBs for a client and 4 of the 6 failed, we also just tested 480 - 250 amps CBs and all passed, different manufacture.
Click to expand...

Brian, just to clarify, what do you mean by failed?

  • The breaker never opened?
  • The breaker opened above stated capacity?
  • The breaker open below stated capacity?
  • The breaker was slower or faster than it was supposed to be?
 
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