Manufacturer's MOCP vs. Breaker Size
- Thread starter Keri_WW
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- Location
- Massachusetts
If you receive a non-standard amperage size from the manufacturer for their equipment's MOCP, such as 106A, is it acceptable to use the next size up breaker (per 240.4) in this case 110A or do I need to use 100A?
Thanks,
Keri
240.4 does not apply to this.
Maximum is maximum. You cannot use more than the max.
- Location
- New Jersey
- Occupation
- Journeyman Electrician
texie
Senior Member
- Location
- Fort Collins, Colorado
- Occupation
- Electrician, Contractor, Inspector
If you receive a non-standard amperage size from the manufacturer for their equipment's MOCP, such as 106A, is it acceptable to use the next size up breaker (per 240.4) in this case 110A or do I need to use 100A?
Thanks,
Keri
I never seen a Max OCPD value listed on a label that did not correspond to a standard value. I'm not even sure if the listing standard would allow this. Do you have such a case?
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
That was my thought. Recently saw MOCP of 17 on plans and assumed it was a typo, and it was.
- Location
- Illinois
- Occupation
- retired electrician
I have seen equipment like generators with non-standard breaker sizes. I expect that if you want to pay for it, you can get any current rating that you want to.
It may be difficult to convince the manufacturer today to do a special calibration because of the automated manufacturing process used today.But over 30 yesrs ago in the good old days such modifications were commonly avsilable. But the UL489 listing is lost.
Last edited:
- Location
- Illinois
- Occupation
- retired electrician
The 489 standard only permits specific amp ratings?
UL listing generally cover those ratings as included in NEC art 240.6, continuous Ampere tatings. Unless the manufacturer submits other ratings to be listed those would be the only rating that would be listed the to the cost of sunning them for testing.
The only rating that may by listed other than that we which are included in NEC art 240-6 is a 10a rated breaker as I can recall. But the carte blanche ratings for UL489 doesn't exist to my knowledge.
When quoting other that a standard rating that is on thing that I did was to specifically state that it was nonUL with special calibrations because it would otherwiseassumed to be be considered UL listed by the customer.. Otherwise they will ask where the UL sticker was.
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