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#23709 - 03/25/03 09:58 PM Capacity debate (what a circuit can handle)  
LuminateME1  Offline
Member
Joined: Mar 2003
Posts: 22
Seattle,WA,USA
What can a 15 amp breaker hold (as far as watts). Also 20 amp--30 amp--and 40 amp. Heck we are in great debate over this issue. It's in the book, but many people have their own ideas. I know that we are to use only 80% of it's actual capacity. Example: Lets say a 15 amp breaker can handle 1800 watts max. I would then use only 80% of that capacity. So: 1440 watts would be the most I would put on that one circuit. Would love to hear you input. Heck, debate me down baby! LOL


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#23710 - 03/25/03 10:01 PM Re: Capacity debate (what a circuit can handle)  
harold endean  Offline
Member
Joined: Feb 2002
Posts: 2,233
Boonton, NJ
When you say, "What can a 15 amp circuit breaker hold?" What do you mean? What it REALY can hold? Or what you install on it? Most electricians use the 80% rule. (I believe)A 15 amp breaker can hold more than 15 amps, this way it can be used for the start up of motors and HVAC equipment.


#23711 - 03/25/03 10:13 PM Re: Capacity debate (what a circuit can handle)  
HotLine1  Offline


Member
Joined: Apr 2002
Posts: 6,863
Brick, NJ USA
Now we are asking a "debate" question.....
IF it is an FPE 15 amp breaker (stab-loc) it may "hold" at 100 amps for a few.....it also may hold at 35 for a while......
A 15 will trip at the rated current based on the time curve calculated by the factory.

Harold is correct that a cb can "hold" to allow motor start-up, that is also based on the time curve.

You can obtain time curve info from the mfg's, and there is a lot of time curve info at Bussman Fuses.

John

The 80% rule is used.


John

#23712 - 03/25/03 10:14 PM Re: Capacity debate (what a circuit can handle)  
LuminateME1  Offline
Member
Joined: Mar 2003
Posts: 22
Seattle,WA,USA
To clarify what I meant (sorry): What can a 15 amp breaker hold on a circuit being ran for a single family home dewelling. How many openings?


#23713 - 03/26/03 07:07 AM Re: Capacity debate (what a circuit can handle)  
iwire  Offline
Moderator
Joined: Jan 2003
Posts: 4,391
North Attleboro, MA USA
A 15 amp breaker can be loaded up to 15 amps for Non-continuous loads.

For continuous loads no more then 12 amps (80%)

The code does not use 80% as the terminology they have you calculate a continuous load circuit at 125%, but the result is the same


Bob Badger
Construction & Maintenance Electrician
Massachusetts

#23714 - 03/26/03 08:22 AM Re: Capacity debate (what a circuit can handle)  
Redsy  Offline
Member
Joined: Mar 2001
Posts: 2,056
Bucks County PA
Contrary to popular belief, the NEC does not limit the number of receptacle outlets on a residential circuit. However, many use the 180 VA rule which will result in 8-10 outlets (dpeending on if you apply the 80% rule) on a 15 amp ckt.
The other side of the argument is that the more receptacles you install, the less likely extension cords will be used.


#23715 - 03/26/03 01:18 PM Re: Capacity debate (what a circuit can handle)  
DBC1  Offline
Member
Joined: Mar 2003
Posts: 16
Tulsa, OK USA
I believe iwire has the correct answer. 15 amps for non continious, and 12 for continious. [Linked Image]


#23716 - 03/30/03 07:25 PM Re: Capacity debate (what a circuit can handle)  
wocolt  Offline
Member
Joined: Dec 2002
Posts: 110
{QUOTE]DBC1 --I believe iwire has the correct answer. 15 amps for non continious, and 12 for continious.{/QUOTE]
This is residential right ? where is there a continuous load...?
by definition continuous load is 3hours or more. Just askin'

WOC


#23717 - 03/30/03 10:18 PM Re: Capacity debate (what a circuit can handle)  
elecbob  Offline
Member
Joined: Aug 2002
Posts: 141
WA
Whatever happened to 3 watts SQ/FT for receptacle and lighting loads in SFR's?
bob


#23718 - 03/30/03 10:31 PM Re: Capacity debate (what a circuit can handle)  
LuminateME1  Offline
Member
Joined: Mar 2003
Posts: 22
Seattle,WA,USA
to answer your question Wocolt. Yes, it's residential. Thanks for the responses!



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