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#23709 - 03/25/03 05:58 PM Capacity debate (what a circuit can handle)
LuminateME1 Offline
Member

Registered: 03/06/03
Posts: 25
Loc: 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 06:01 PM Re: Capacity debate (what a circuit can handle)
harold endean Offline
Member

Registered: 02/16/02
Posts: 2248
Loc: 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.

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#23711 - 03/25/03 06:13 PM Re: Capacity debate (what a circuit can handle)
HotLine1 Offline

Member

Registered: 04/03/02
Posts: 6805
Loc: 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

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#23712 - 03/25/03 06:14 PM Re: Capacity debate (what a circuit can handle)
LuminateME1 Offline
Member

Registered: 03/06/03
Posts: 25
Loc: 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?

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#23713 - 03/26/03 03:07 AM Re: Capacity debate (what a circuit can handle)
iwire Offline
Moderator

Registered: 01/05/03
Posts: 4343
Loc: 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

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#23714 - 03/26/03 04:22 AM Re: Capacity debate (what a circuit can handle)
Redsy Offline
Member

Registered: 03/28/01
Posts: 2138
Loc: 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.

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#23715 - 03/26/03 09:18 AM Re: Capacity debate (what a circuit can handle)
DBC1 Offline
Member

Registered: 03/15/03
Posts: 18
Loc: Tulsa, OK USA
I believe iwire has the correct answer. 15 amps for non continious, and 12 for continious.

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#23716 - 03/30/03 03:25 PM Re: Capacity debate (what a circuit can handle)
wocolt Offline
Member

Registered: 12/06/02
Posts: 117
{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

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#23717 - 03/30/03 06:18 PM Re: Capacity debate (what a circuit can handle)
elecbob Offline
Member

Registered: 08/23/02
Posts: 142
Loc: WA
Whatever happened to 3 watts SQ/FT for receptacle and lighting loads in SFR's?
bob

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#23718 - 03/30/03 06:31 PM Re: Capacity debate (what a circuit can handle)
LuminateME1 Offline
Member

Registered: 03/06/03
Posts: 25
Loc: Seattle,WA,USA
to answer your question Wocolt. Yes, it's residential. Thanks for the responses!

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