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Thread: Number of recepts on a 20A branch circuit

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    Number of recepts on a 20A branch circuit

    Hi,

    Trying to reconcile NEC 2008 210.21(B)(2) with 220.14(I), specifically Exhibit 220.4 which is in the 2008 Handbook. See attached for the two excerpts.

    I had previously convinced myself that the maximum number of convenience outlets that could be on a single 20A branch circuit is 13. (180VA per outlet * 13 outlets = 2340VA, which is under 20A*120V=2400VA). This was under the assumption that the NEC prescribed load for convenience outlets already takes into account continuous vs non-continuous loading. Exhibit 220.4 also shows 13 outlets on a 20A branch circuit.

    Now reading 210.21(B)(2) I'm not so sure. Has anybody else noticed this apparent contradiction? What's the actual max # of outlets on a 20A circuit?

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    Residential = no limit.

    Commercial / Industrial = Determined by load(s).

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    Quote Originally Posted by shespuzzling View Post
    Has anybody else noticed this apparent contradiction?
    I'm not seeing what the contradiction is.

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    If the max load allowed on a 20A branch circuit is 16A (per 210.21(b)(2)), then that means a maximum of (10) 180VA convenience outlets. However the exhibit referenced shows 13 convenience outlets, which would be a total ampacity of 19.5A at 120V.

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    Quote Originally Posted by shespuzzling View Post
    If the max load allowed on a 20A branch circuit is 16A (per 210.21(b)(2)),
    That's not what 210.21(B)(2) says.

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    ahhh got it, so the maximum indicated in 210.21(b)(2) is for a cord and plug connected load on a single receptacle? So even if I had a non-continuous cord and plug load rated at 20A, I'd have to use a 30A branch circuit and receptacle.

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    At the risk of being chastised again, I will restate my opinion, long held and frequently contradicted, that 210 and 220 don't speak with one another. The 180 VA per outlet is for calculating the minimum load for the building. It is not a design criterion. So my belief is that there are no limits to the number of outlets on a circuit, regardless of the occupancy. Specifically, when article 210.21(B) speaks of maximum loads, nothing requires us to count the outlet at 180 VA each. Instead, it is talking about what gets actually plugged into the outlet.

    You may fire when ready, Gridley.
    Charles E. Beck, P.E., Seattle
    Comments based on 2017 NEC unless otherwise noted.

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    Quote Originally Posted by shespuzzling View Post
    ahhh got it, so the maximum indicated in 210.21(b)(2) is for a cord and plug connected load on a single receptacle? So even if I had a non-continuous cord and plug load rated at 20A, I'd have to use a 30A branch circuit and receptacle.
    No, a 20 amp or larger single receptacle on a 20 amp individual branch circuit can have a 20 amp non-continuous load.

    210.22 Permissible Loads, Individual Branch Circuits.
    An individual branch circuit shall be permitted to supply
    any load for which it is rated, but in no case shall the load
    exceed the branch-circuit ampere rating.
    Rob

    Moderator

    All responses based on the 2014 NEC unless otherwise noted

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    But if you have convenience outlets and you're not designing for a particular cord and plug connected appliance you have to assume 180VA at a minimum, which would mean 13 outlets maximum.

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    Quote Originally Posted by charlie b View Post
    At the risk of being chastised again, I will restate my opinion, long held and frequently contradicted, that 210 and 220 don't speak with one another. The 180 VA per outlet is for calculating the minimum load for the building. It is not a design criterion. So my belief is that there are no limits to the number of outlets on a circuit, regardless of the occupancy. Specifically, when article 210.21(B) speaks of maximum loads, nothing requires us to count the outlet at 180 VA each. Instead, it is talking about what gets actually plugged into the outlet.

    You may fire when ready, Gridley.

    I'll fire.

    Article 220 is for calculating branch cir, feeders, services. Section 220.14(I) states 180va per receptacle but this section is under Part II which states Branch Circuit Load Calculation. So part II says branch circuit load calculation and 220.14(I) states 180 per receptacle then how do you reconcile your statement. IMO, it is saying that the branch circuit cannot have more than 180 va per receptacle.
    They say I shot a man named Gray and took his wife to Italy
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