circuit breaker trip guidlines

[arcblast]

Hello,

just a question on the waranty, regulations or other requirements of circuit breakers ?...specifically:
how many times do they have to trip correctly after installed.
or do they have any regulations holding manufacturers to how many times you can safely reset them....?

Thanx in advance, Mike

 

[hurk27]

Re: circuit breaker trip guidlines

I know there is nothing in the NEC that would say this but maybe UL might have a guidline to go by.
try UL's web site

 

[arcblast]

Re: circuit breaker trip guidlines

Wow...

Looks like I got alot of digging to do here....so much info....I will very busy at this website...thanx for the help...just wish it was a little more specific....lol...

thanx, Mike

 

[rbalex]

Re: circuit breaker trip guidlines

Quoting from IEEE 1015 Applying Low-Voltage Circuit Breakers Used in Industrial and Commercial Power(the "Blue Book"):
Systems

3.35 Circuit breaker useful life
It is prudent to replace any MCCB that has interrupted, at most, two faults at rated maximum
current. This is so because the MCCB short-circuit proof test consists of an ?O-t-CO
sequence, which means that in proof testing of the circuit-breaker design and in periodic fol-
low-up testing thereafter, the circuit breaker is required to open a fault from an initially closed
position (corresponding to the ?O? operation), then after a period of time (t) to reset is
allowed, to be closed into a maximum fault and trip open for a second time (corresponding to
the ?CO? operation). This demonstrates a circuit breaker?s ability to perform at least two
maximum level fault interruptions with the second at least a little worse than the first. No
maintenance of the circuit breaker on test is permitted between interruptions.

It then goes on to refer to NEMA Standard AB-4.

Both NEMA AB-4 [MCCB PM] and AB-3 [MCCB Applications] are free downloads at:
http://www.nema.org/help/docno.html

 

[templdl]

Re: circuit breaker trip guidlines

I believe your are referring to UL489 Test requirements.
The reference that I have shows that among these tests are that:
All breakers shall calibrated to carry their continuous rating in an ambient temp. of 40degC.
200% calibration check
135% calibration check
Overcurrent tests at 600% normal current at rated voltage for breakers up to 1600a: 50 operations.
Endurance tests (number of operations), ratings 0-100a, 6000FL, 4000NL @ 6/min., ratings 101-225a, 4000FL, 4000NL @5/min., 226-600a, 1000FL, 5000NL @4/min. Etc.
After the endurance tests the breaker again must pass calibration tests at 200% and 135% ratings.
It must also pass short circuit tests at its rated voltage at its value for example:
Breakers 250v and below and 100a and below (3-pole breakers in this example), each individual pole amps 4,330 , common pole amps 5,000, 7 test total.
After the short circuit test the breaker must again pass a calibration test at 200% of its rating.

A sample lot of breakers must pass these tests to achieve the initial standard U.L listing. After passing these tests addition higher interrupting tests may be conducted for the particular rating desired.

 

[arcblast]

Re: circuit breaker trip guidlines

Thanx for the great info folks !!!

Just another quick question: is there a standard warranty or guarantee that the manufacturers are puting on these products ?...have you seen any ?
If so , what is the makers warranty ?...

Thanx again for the great help !!!

Mike

 

[templdl]

Re: circuit breaker trip guidlines

Usually one year from date of invoice(shipment).
There is one manufacturer that I know of that has a has a 1-year from date of installation or 18 months from date of shipment (invoice) which ever comes first.
There may also be some specific warranties which could be longer than the standard warranty for load center and UL certified breakers which may provide a competitive advantage for a manufacturer.

 

[jim dungar]

Re: circuit breaker trip guidlines

This is from a manufacturer's warranty.

The...[XXX] Residential Products Limited Warranty.

"...its branch circuit breakers...for the lifetime of the load center in which it is installed."

"...its single phase load centers...for 10 years from date of installation..."

"...warranties are void if...other than the...breakers marked on the...label or wiring diagram."

".... warranty covers residential use ... and excludes any commercial applications."

[ May 27, 2004, 03:07 PM: Message edited by: jim dungar ]

 

[arcblast]

Re: circuit breaker trip guidlines

Thank you kindly for the info...

Mike