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
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
is this a residential application ?
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.
Charles E. Beck, P.E., Seattle
Comments based on 2017 NEC unless otherwise noted.
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.
That's 220.3(B)(9) in the 2002 and it doesn't apply to dwellings.By bh:
Per NEC 220.14(I) each receptacle on one yoke shall be calculated at not less than 180va.
[ August 09, 2005, 12:48 PM: Message edited by: physis ]
Sam, San Francisco Bay Area
Killer 76
We need to know if it's for residential,commerial or industial.
Jim
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
Moderator
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.Originally posted by roger:Bh, why would you consider a receptacle circuit continuous unless you knew specifically what the use was?
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.
Charles E. Beck, P.E., Seattle
Comments based on 2017 NEC unless otherwise noted.
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.
Just because you can, doesn't mean you should.
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