Thread: number of receptacles on a circuit

1. Member
Join Date
Feb 2004
Posts
44

number of receptacles on a circuit

could someone please help me find the location in the code book on how many 20 amp receptacles can be installed on (1) 20 amp breaker

also a method to add a combined number of receptacles

15 and 20 amp

Thanks
Robert

2. Senior Member
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Jan 2005
Posts
3,034

Re: number of receptacles on a circuit

is this a residential application ?

3. Re: number of receptacles on a circuit

This has been discussed several times on this Forum. May I ask you to do a word search, and see if you can find your answer?

This might be a good topic for inclusion in the FAQ section. However, given the strongly opposing points of view that have been expressed on this topic, I don't know if I would be willing to write up the "correct" answer for the FAQ.

4. Re: number of receptacles on a circuit

Here are a few threads you can check out.

1

2

3

Roger

5. bh
Junior Member
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Aug 2004
Posts
23

Re: number of receptacles on a circuit

Per NEC 220.14(I) each receptacle on one yoke shall be calculated at not less than 180va. A 20 amp breaker serving non-continuous loads has a capacity of 20 amps time 120 volts or 2400va. 2400 divided by 180 is 13.33 so you can put 13 receptacles on one 20 amp breaker. I assume each breaker to be continuously loaded so the max available current on a 20a breaker is 16 amps. I look at the area the receptacle is serving and decide if 180 is OK. Also putting 13 receptacles on a circuit doesn't allow for adding any more receptacles in the future. I limit the receptacles to about 6- 8 on a circuit.

6. Re: number of receptacles on a circuit

By bh:

Per NEC 220.14(I) each receptacle on one yoke shall be calculated at not less than 180va.
That's 220.3(B)(9) in the 2002 and it doesn't apply to dwellings.

[ August 09, 2005, 12:48 PM: Message edited by: physis ]

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Iowa
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Re: number of receptacles on a circuit

Killer 76
We need to know if it's for residential,commerial or industial.
Jim

8. Re: number of receptacles on a circuit

If it's residential, put as many as you can afford to buy on the circuit.

Other than residential, 220.3(B)(9) as pointed out by Physis.

Bh, why would you consider a receptacle circuit continuous unless you knew specifically what the use was?

Roger

9. Re: number of receptacles on a circuit

Originally posted by roger:Bh, why would you consider a receptacle circuit continuous unless you knew specifically what the use was?
I would never treat a receptacle circuit as "continuous," regardless of what is plugged in, if by that you mean that you would multiply the 180 VA times 125%. Our design and installation efforts are based on 180 VA, not on any potential future use of the receptacle.

But homeowners have a constraint of which they are likely unaware. If I had a single, large, plug & cord, not-permanently mounted item (e.g., hair dryer) plugged into a 20 amp receptacle outlet that is part of a 20 amp branch circuit, that one item is not allowed to be more than 16 amps (1920 VA). But I can still plug 4 more amps worth of other stuff (480 VA) into other receptacles on the same branch circuit.

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Re: number of receptacles on a circuit

Charlie
Just to be difficult.
16A is 1920VA at 120V. If the load is a hair dryer, it can be rated by UL as 2000W at 125V maximum. Because it is primarily a resistive load using it at 120V would reduce it's current draw as well as it's heat output.

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