mistabass
Member
- Location
- Rhode Island
I don't do resd. 2 questions how many recp. can you put on 15 amp circuit i say doesn't matter. the guys say you can only go 80% of the breaker ampacity i laught at them hope i am wright
discusion at work
- Thread starter mistabass
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peter d
Senior Member
- Location
- New England
I would have laughed too. You are correct.
Just make sure that when you are talking about the 80% rule, that only applies to continuous loads. It's not an across the board rule that you can only load a breaker 80%.
SiddMartin
Senior Member
- Location
- PA
just throwin it out there, aren't breakers only rated 80% though? you can buy 100% breakers but they're expensive. Never fully understood this
peter d
Senior Member
- Location
- New England
I'm not really sure where that idea came from but it sounds like a really good trade myth to me.
You can load an OCPD to its handle rating for 2 hours, and 59 seconds and then shut it off and you are fine. The 80% rating applies to continuous loads only.
mistabass
Member
- Location
- Rhode Island
thanks guys i know who is buying lunch tomm.
SiddMartin
Senior Member
- Location
- PA
I'm not really sure where that idea came from but it sounds like a really good trade myth to me.
You can load an OCPD to its handle rating for 2 hours, and 59 seconds and then shut it off and you are fine. The 80% rating applies to continuous loads only.
I understand the continous load rule,but, but I think breakers are only rated at 80%. i'm hopin someone chimes in and shines some light on this for me.
peter d
Senior Member
- Location
- New England
You're making this too complicated. It's really that simple...breakers are rated at their ampacity. The limitation on the ampacity is because of the continuous load rule.
mistabass
Member
- Location
- Rhode Island
call me crazy i always thought 20 amp brk was good up to 20 amp draw
I understand the continous load rule,but, but I think breakers are only rated at 80%. i'm hopin someone chimes in and shines some light on this for me.
Breakers are rated for 100% of the load. "Continuous load" derating only applies to conductors.
A 20a breaker can actually hold more than 20 amps. It will not magically trip at 20.0000001 amps, but the higher the amperage goes, the quicker it trips. 21 amps may never trip it, 22 amps may take 4 hours, 23 amps may take an hour, 24 amps may take 10 minutes.... It's called a trip rating curve or something like that.
I'll be there! Where is it?
SiddMartin
Senior Member
- Location
- PA
You're making this too complicated. It's really that simple...breakers are rated at their ampacity. The limitation on the ampacity is because of the continuous load rule.
well that cleared it up rather quickly
peter d
Senior Member
- Location
- New England
No, you're not crazy. You're correct.
peter d
Senior Member
- Location
- New England
Where in RI are you? I get a cut of your free lunch for helping you out.
SiddMartin
Senior Member
- Location
- PA
...................
SiddMartin
Senior Member
- Location
- PA
"Various types of low-voltage circuit breakers have differing continuous
duty capabilities. Some are rated to carry 100 percent of
their trip rating continuously while others are rated to carry only
80 percent of their trip rating continuously. It is important that we understand
the difference and apply these breakers properly"
duty capabilities. Some are rated to carry 100 percent of
their trip rating continuously while others are rated to carry only
80 percent of their trip rating continuously. It is important that we understand
the difference and apply these breakers properly"
mistabass
Member
- Location
- Rhode Island
providence thanks for the imput this is a great forum you guys really know your stuff
peter d
Senior Member
- Location
- New England
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Ask how much of that 80% they assign to each receptacle. Then remind them that one 15a receptacle is 100% of a 15a circuit.
Inverse time curve
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
Before anyone starts claiming a free lunch at someone else's expense, let me say that I think the wrong answer has been given. I don't want this to become a side track or a rehash of old discussions. But I will say that I don't believe there is any limit to the number of receptacles you can put on a circuit. I will add that it does not matter whether you are talking residential or not.
I will conclude with a request (demand, actually) that before either (1) you ask me to explain my reasoning, or (2) you try to tell me my answer is wrong, you first go find the other threads (there are several) in which this issue has been debated. Tell me you have read the other threads, before posting a comment in favor of, or in opposition to, my statement.
We now return you to your regularly scheduled discussion. :grin:
I will conclude with a request (demand, actually
) that before either (1) you ask me to explain my reasoning, or (2) you try to tell me my answer is wrong, you first go find the other threads (there are several) in which this issue has been debated. Tell me you have read the other threads, before posting a comment in favor of, or in opposition to, my statement.We now return you to your regularly scheduled discussion. :grin:
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