GE Breakers

[czars]

Has anyone had an experience with GE 2 pole breakers failing to trip when overloaded to 1.5+ times their rating for extended periods of time?

 

[GoldDigger]

Has anyone had an experience with GE 2 pole breakers failing to trip when overloaded to 1.5+ times their rating for extended periods of time?

Possibly cold outdoor ambient temperatures?

 

[ATSman]

Also old age. We have done forensic tests for insurance co's after houses and trailers have burnt down.
Even new equipment fail OC tests. They are so cheap (and low quality assurance) that they are never acceptance tested or maintenance tested until a tragedy occurs when they don't trip.

 

[iceworm]

Has anyone had an experience with GE 2 pole breakers failing to trip when overloaded to 1.5+ times their rating for extended periods of time?

What type CB? What did the time-current trip curve show?

If it is a UL 489 breaker, the 25C specs are:

200%, 0-30A, 2 minutes
200%, 31-50A, 4 minutes
135%, 0-50A, within one hour
100%, never trip (test until temperature stabilizes)​

For example, at 150%, trip in 59 minutes meets UL spec.

Time-current curve would be closer.

ice

 

[kwired]

Has anyone had an experience with GE 2 pole breakers failing to trip when overloaded to 1.5+ times their rating for extended periods of time?

Can you tell us what kind of time period you are referring to, as iceworm pointed out a properly functioning breaker can carry what some may think is surprising for fairly long time. The more the overload the faster it will trip though. Ambient temp at the breaker location will have some impact as well.

 

[paul]

Has anyone had an experience with GE 2 pole breakers failing to trip when overloaded to 1.5+ times their rating for extended periods of time?

Yep. Which is why one of the data centers I service requires every newly installed breaker to be tested.

 

[jim dungar]

Yep. Which is why one of the data centers I service requires every newly installed breaker to be tested.

How does that change the fact the breaker is doing what it is supposed to do - trip after 59 minutes? In a chilled data center the time would be even longer.

 

[paul]

How does that change the fact the breaker is doing what it is supposed to do - trip after 59 minutes? In a chilled data center the time would be even longer.

I did not read enough information in the OP to come to a conclusion as to whether is was tripping correctly or incorrectly. How did you come to the conclusion that it's a fact that it was doing what it was supposed to do.

 

[iceworm]

... one of the data centers I service requires every newly installed breaker to be tested.

just curious - what spec do you test to?

ice

 

[paul]

just curious - what spec do you test to?

ice

I do not have the specs. We send them to a breaker shop that does the testing. I know that when I do on site large frame breaker testing with them, they use the manufacturers specs to test them. So I would be willing to bet that they use whatever GE specs on the THQB's.

 

[jim dungar]

I did not read enough information in the OP to come to a conclusion as to whether is was tripping correctly or incorrectly. How did you come to the conclusion that it's a fact that it was doing what it was supposed to do.

The OP simply said 'extended times'. I never said his breaker was working.

I asked how testing a breaker would affect the fact that it takes an 'extended time' to trip at 150% loading, when the breaker is operating correctly.
Then I commented how the actual tripping time would be different in the <40?C ambient of most data centers.

Very few people ask for field testing of thermal magnetic breakers in the thermal region, due to the influence of, and lack of control over, ambient temperatures.

 

[kwired]

Yep. Which is why one of the data centers I service requires every newly installed breaker to be tested.

I don't expect to have to test new breakers to make sure they are good, but I don't usually buy GE unless there is an existing GE panel that I am running a new circuit to. I find it a little hard to believe their QC is that bad, but maybe it is. I do know the standards allow for a breaker to hold for time/amperage levels that some may think are kind of long/high, but remember these breakers are primarily protecting conductors, if you have certain equipment that you want more protection on then maybe some supplemental protection that meets the needs at that equipment is what is needed.

 

[iceworm]

... We send them to a breaker shop that does the testing. ... So I would be willing to bet that they use whatever GE specs on the THQB's.

Just curious - Do they check the instantaneous portion of the trip curve?

ice

 

[iceworm]

... I do know the standards allow for a breaker to hold for time/amperage levels that some may think are kind of long/high, but remember these breakers are primarily protecting conductors, if you have certain equipment that you want more protection on then maybe some supplemental protection that meets the needs at that equipment is what is needed.

Just some personal design philosophy - certainly no minimalistic code:

Other than #14, #12 residential recetpacle circuits, OCPD does not protect the equipment, and does not always protect the conductors. Example motors: The motor is protected from overload by the design. The overloads are there to catch minor mechanical faults before the motor has a chance to burn up. One might say these are repairable. If the motor faults to where the CB trips, there is no motor to save - it's dead. The ocpd operates to put out the fire and hopefully trips inside of the conductor damage curve. Although, except for large feeders (say >1000A), the cable damage curve is rarely on the coordination curves. Still, one might say it could protect the couductors here.

Now, if the conductors develop a fault (forklift attack) again there are no conductors to save. The ocpd is there to put out the fire.

The ocpd is for protecting the structure.

JAO

ice

 

[iceworm]

Yep. Which is why one of the data centers I service requires every newly installed breaker to be tested.

Second curiousity question. Concerning smaller molded case CBs (GE THQB, SQD QO and the like)
What do you se for a failure rate? As in the CBs do not meet spec and are not used.

ice

 

[kwired]

Just curious - Do they check the instantaneous portion of the trip curve?

ice

And at max interrupt rating ranges

Maybe they should check fuses before using them as well

 

[iceworm]

And at max interrupt rating ranges

Maybe they should check fuses before using them as well

Hey - I am keeping my tongue -- ahhh - fingers firmly in cheek. You are having too much fun.:roll:

ice
(emoticon substituted for invisible body language)

 

[jim dungar]

Although, except for large feeders (say >1000A), the cable damage curve is rarely on the coordination curves. Still, one might say it could protect the couductors here.

Among other reasons, I believe, this is part of why UL489 requires conductors (i.e. 4feet of rated size) to be connnected to the breaker during testing. If the conductors, or terminations, are damaged the test has been failed.

 

[kwired]

And at max interrupt rating ranges

Maybe they should check fuses before using them as well

Hey - I am keeping my tongue -- ahhh - fingers firmly in cheek. You are having too much fun.:roll:

ice
(emoticon substituted for invisible body language)

I got to go through the plant where they make QO breakers back in about 1988 or 1989 IIRC. One part I can't forget was testing lab and watching them test a 10kAIC breaker with a 10kA source - three pole breaker with all three outputs tied together, then closed in a pretty heavy walled cabinet. They "turned on the juice" and it made a hell of a bang and smoke was coming out some of the edges of the heavy door. They opened the door, more smoke rolled out, the breaker was tripped, they turned it off then back on and it stayed set, but didn't look like you would really want to use it again.

 

[paul]

And at max interrupt rating ranges

Maybe they should check fuses before using them as well

Now you're just being an ass.