circuit Interrupter Rating

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inspector23

inspector23

Senior Member
Location
Temecula, CA
In the factory manufactured main lug circuit breaker panel for swimming pool motors and equipment, the manufacturer states that the CB?s have to be rated at 10,000 amp interrupting rating.



The minimum standard CB?s have a 5,000 amp interrupting rating. I know the electricians have to use the proper interrupting rated CB because it is listed by the manufacturer, but my question is why this installation for pool equipment requires a 10,000 amp interrupting rating instead of the 5,000 .

I would like to be able to explain a little more than just "because the manufacturer listed it for 10,000 amps." I know that in itself is a legitimate reason and cause enough for a correction notice, I am just looking for the reason WHY.






Any help would appreciated!
 
About all Big Orange and Big BLue carry in SoCal is 5,000. At least I believe they are 5,000, as they are not specifically marked otherwise and if not marked otherwise, the code says they are treated as 5,000.

Still would like to be able to give the electrician something besides "listed" as the reason for the correction notice. Would be nice to know why.
 
SqD breakers have 10kAIC on the breaker. The 'H' breakers are rated at 5kAIC.
I believe CH is also 10kAIC.
 
Does 240.86 (B)(2) apply?
Is the sum of the FLA of all the motors greater than 50A (1% of 5,000)?
 
Found a very appropriate article which summarizes a good Bussman article here. The epr-1 document from bussman has a little more explanatory material, but this version from mike holt actually has a sample inspection page with all the appropriate articles!

Obviously, the manufacturer provides instructions for UL listing. In this case, I do not know what UL standard applies. But if every other pool pump is shipped with no (i.e., 5K) requirement, then it stands to reason that either their pump motor is cheap (insufficient copper to provide the available interrupting current of everyone else's) or the manufacturer added the 10K requirement beyond the minimum in the standard by choice. This is certainly their decision to make.

As to why, why not keep it simple. SCCR, for practical reasons, means that the points in the breaker will still separate even if there's an arcing fault in the breaker.
 
I can't think of any legitimate reason as to why the manufacturer would make such a statement. The kaic requirement is based upon the available fault current which the manufacturer has no idea as to what the value is. By specifying a 10kaic breaker that doesn't guarantee any magical current limiting capabitiy to protect the downstream load so that thought is out.
Service entrance panel a commonly rated 10kaic and it would be my best guess that their intent is to duplicate that "assumed" rating. So to say that 5kaic would a allowable rating for a down stream device when their may be 10ka fault current available would be an incorrect application.
The same issue would arise if the SE panel was required to be 22kaic then would a 10kaic rated downstream device be allowed? Not unless on did an actual fault current coordination study done by a qualified person to deterine what the actual available fault current would be at the location of the downstream device which would be unreasonable to do.
It is of my opinion that the manufacturer's statement is misleading and should direct the installer to the SE panel and duplicate the kaic rating at that SE panel.
 
So they would have to have a 10KAIC rated branch breaker even if the service only has 4KAIC of available fault current?

Steve
 
steve66,
Re. the 4kaic, how would that be determined?
Also, if the directions state the 10kaic devices are required then they must be provided er NEC 110.3(B) even though it may not make sense. But, even so, that may be wrong would the be more than 10ka fault current available.
 
In most areas, can't the POCO provide a rough figure for the available fault current so any service equipment requirement can be knowingly met? I was told most res. systems will be under 10,000 by the POCO here. I think as it was said that the manufacturer is aiming for a margin of CYA here, and does not want their product to be the weak link should anything happen.
 
Even if POCO could, the installed panel still has a minimum 10,000 amp rating listed from the manufacturer, therefore the circuit breakers have to meet that requirement - no matter what the POCO may advise for res services.

"Hey, if this was easy, plumbers would be doing it." :D
 
Well if I am reading the handbook correctly, it says that a lesser rated device can be installed if protected on the line side by a device that is suitable for the available fault current. My handbook is from 1996, 240-83.
But does the breaker have to be series rated? or does that just refer to the use of the different ratings in series?...............But the end use equipment has to be marked as such for the series. Can someone explain this to me..........
 
thank you Don,

I havent been in the Trade long enough to even See a breaker less than 10ka AIC,
and wasnt aware that they could be purchased nowadays
 
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