20A minimum CB
- Thread starter lizzie14
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Re: 20A minimum CB
For UL489 devices the minimum is 15a. Even though there are some 10a rated devices of the same frame size I'm not aware that there any that are available with a UL489 listed.
Reference 240.6 Standard Ampere ratings.
There are UL1077 supplementary protectors for a wide range of amp ratings available but they must be applied per 240.10 and are not to considered as a substitute for branch circuit over-current protection. The are available in ampacities in a range of .5a to about 60a. However, they are different than the UL489 devices in that they are often available with a choice of at least 2 time/current trip curves.
Again, they can not be used as a subsitute for a UL489 listed device.
For UL489 devices the minimum is 15a. Even though there are some 10a rated devices of the same frame size I'm not aware that there any that are available with a UL489 listed.
Reference 240.6 Standard Ampere ratings.
There are UL1077 supplementary protectors for a wide range of amp ratings available but they must be applied per 240.10 and are not to considered as a substitute for branch circuit over-current protection. The are available in ampacities in a range of .5a to about 60a. However, they are different than the UL489 devices in that they are often available with a choice of at least 2 time/current trip curves.
Again, they can not be used as a subsitute for a UL489 listed device.
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Re: 20A minimum CB
Square D (I did not check others) lists QO breakers from 10 to 150 as meeting UL 489.
Square D Info
Square D (I did not check others) lists QO breakers from 10 to 150 as meeting UL 489.
Square D Info
lady sparks lover
Senior Member
Re: 20A minimum CB
I thought 15 is usually the lowest in a panel, because I don't see many of those either.
Lady
I thought 15 is usually the lowest in a panel, because I don't see many of those either.
Lady
Re: 20A minimum CB
Yes, I did notice that not only SqD but C-H has UL489 listed 10a breakers available which were not a number of years ago. But other than being used within UL listed assemblies I can't see how they would be applied within the NEC requirements even though there may even be a few other ratings that are UL listed that are not included in the standard ratings in the NEC.
Yes, I did notice that not only SqD but C-H has UL489 listed 10a breakers available which were not a number of years ago. But other than being used within UL listed assemblies I can't see how they would be applied within the NEC requirements even though there may even be a few other ratings that are UL listed that are not included in the standard ratings in the NEC.
Re: 20A minimum CB
Would these be for de-rating conductors due to 310.15B2a or high ambient conditions??? For 14 gauge, that would be more than 9 in 1 conduit, for 12 gauge, that would be 21 or more in 1 conduit... do you need to limit only the load, or the breaker and the load?
I HAVE seen one 10A QO used as a supply to a transformer that powered a load sequencer in a panel for a theater audio system. The unit is built in to a connected box to the side of a QO load center, and uses _motorized_ QO breakers(don't see many of those!) to sequence the loads when you push a Start/Stop station.
There are pictures, etc at this site.
Mike
Would these be for de-rating conductors due to 310.15B2a or high ambient conditions??? For 14 gauge, that would be more than 9 in 1 conduit, for 12 gauge, that would be 21 or more in 1 conduit... do you need to limit only the load, or the breaker and the load?
I HAVE seen one 10A QO used as a supply to a transformer that powered a load sequencer in a panel for a theater audio system. The unit is built in to a connected box to the side of a QO load center, and uses _motorized_ QO breakers(don't see many of those!) to sequence the loads when you push a Start/Stop station.
There are pictures, etc at this site.
Mike
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