1793
Senior Member
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- Louisville, Kentucky
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- Inspector
What Article in the 2002 NEC best defines the regulation for the number of recptacles or devices per 20amp branch circuit in a single family dwelling?
Number of Recepticals or devices
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jeff43222
Senior Member
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- Minneapolis, Minnesota
Re: Number of Recepticals or devices
None. There is no limit to the number of receptacles on a 20A circuit in a dwelling. I think the limit is 13 receptacles in commercial occupancies, but I'm not absolutely sure because I don't have my handbook in front of me.
None. There is no limit to the number of receptacles on a 20A circuit in a dwelling. I think the limit is 13 receptacles in commercial occupancies, but I'm not absolutely sure because I don't have my handbook in front of me.
- Location
- Lockport, IL
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- Semi-Retired Electrical Engineer
Re: Number of Recepticals or devices
210.11(A) (which, by the way, is not limited to dwelling units) says,
So that leads me to ask two questions:
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I?ve heard that before, and have seen it stated in this forum before. But I am not sure I understand its basis. Can anyone help clarify it for me? Here is what I mean:
210.11(A) (which, by the way, is not limited to dwelling units) says,
220.4 (which, by the way, is also not limited to dwelling units) says,
Finally, 210.3 defines the rating of a branch circuit in terms of its overcurrent device.
So that leads me to ask two questions:
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- <font size="2" face="Verdana, Helvetica, sans-serif">From what code statements may we infer that there is no limit to the number of receptacles on a dwelling unit branch circuit?</font>
- <font size="2" face="Verdana, Helvetica, sans-serif">From what code statements may we infer that there is a limit to the number of receptacles on a commercial facility?s branch circuit?</font>
- Location
- Lockport, IL
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- Semi-Retired Electrical Engineer
Re: Number of Recepticals or devices
You posted your reply while I was typing mine. I have to say that this does not answer my question. That article talks about demand factors, and permits us to add the receptacle load to the lighting load before applying demand factors. But those demand factors (we can chose from two methods) do not apply to a branch circuit, because you won?t get above 3,000 VA on a single branch circuit.
Re: Number of Recepticals or devices
there are no requirements for receptacles in nondwelling applications unless there is a load.
therefore it is assumed if there is a receptacle it will have a load.
In a dwelling there are lots of receptacles required to eliminate the use of extension cords but the load is assumed to not change based on the number of receptacles.
A bedroom with code compliant spacing will have the same load as the same room with receptacles spaced every foot around the room, therefore the number of circuits is based on computed load based on square footage not number of receptacles.
tom
there are no requirements for receptacles in nondwelling applications unless there is a load.
therefore it is assumed if there is a receptacle it will have a load.
In a dwelling there are lots of receptacles required to eliminate the use of extension cords but the load is assumed to not change based on the number of receptacles.
A bedroom with code compliant spacing will have the same load as the same room with receptacles spaced every foot around the room, therefore the number of circuits is based on computed load based on square footage not number of receptacles.
tom
Re: Number of Recepticals or devices
The code does not have a specific requirement as to the amount of receptacles....for dwellinh units.
Yes, the 180VA is for design purposes, but I have to say that you have to keep those 180VA in mind and apply that to the amount of receptacles per breaker...I mean, what is the reasoning behind designing at 180VA per receptacle for the service calculations, then throwing that away and installing a large amount of receptacles on a breaker....it just doesn't make sense right.
The code does not place an exact amount, because for design purposes, not all situations are the same.
If you have a 20A breaker, that's 2400VA total. At 180VA per receptacle, that's 13 receptacles. This might work perfectly in an existing installation.
Personally, when I design I leave a 20-25% "extra room" for future additions, so I only use 16A out of the 20A. With that said, I use 10 receptacles per 20A breakers.
Finally, you have to remember that the Code gets to any number based on probabilities & statistics. Yes 180VA is 1.5A....but that's a very low number. But if you have 10 or 13 receptacles, perhaps you have a TV, a stereo system, and indoor air purifier, etc. Certainly all of those load are going to be higher than 1.5A per load.
The code does not have a specific requirement as to the amount of receptacles....for dwellinh units.
Yes, the 180VA is for design purposes, but I have to say that you have to keep those 180VA in mind and apply that to the amount of receptacles per breaker...I mean, what is the reasoning behind designing at 180VA per receptacle for the service calculations, then throwing that away and installing a large amount of receptacles on a breaker....it just doesn't make sense right.
The code does not place an exact amount, because for design purposes, not all situations are the same.
If you have a 20A breaker, that's 2400VA total. At 180VA per receptacle, that's 13 receptacles. This might work perfectly in an existing installation.
Personally, when I design I leave a 20-25% "extra room" for future additions, so I only use 16A out of the 20A. With that said, I use 10 receptacles per 20A breakers.
Finally, you have to remember that the Code gets to any number based on probabilities & statistics. Yes 180VA is 1.5A....but that's a very low number. But if you have 10 or 13 receptacles, perhaps you have a TV, a stereo system, and indoor air purifier, etc. Certainly all of those load are going to be higher than 1.5A per load.
1793
Senior Member
- Location
- Louisville, Kentucky
- Occupation
- Inspector
Re: Number of Recepticals or devices
I would like to thank everyone that has been responding to my question. I'm glad to know that it's not just me having difficulty finding a clear answer. I have always used "8" per circuit but could not really tell anyone why. I would again like to thank each and everyone of you.
Sincerely,
1793
I would like to thank everyone that has been responding to my question. I'm glad to know that it's not just me having difficulty finding a clear answer. I have always used "8" per circuit but could not really tell anyone why. I would again like to thank each and everyone of you.
Sincerely,
1793
Re: Number of Recepticals or devices
Steve
220.3(B)(11) and its reference to 220.3 (B) (10). In effect, this says you do not have to calculate general purpose dwelling receptacles at 180VA each. I agree with the reason Safari gave. The number of branch circuits are determined by the area served, not by the number of receptacles. The handbook also says the 10-13 restriction does not apply to general lighting or small-appliance branch circuits in dwelling units (Exhibit 220.4).
220.3(B)(9).
Steve
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a.wayne3@verizon.net
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Re: Number of Recepticals or devices
None, is the best reply so far short sweet and to the point.After 2 years I still have to explain to crews that they don`t have to count points on a circuit(residentially).Some of the old timers we have scarf at this and as long as they do the type of work they did I don`t complain.I also add that this is the NEC minimum standard and anything above and beyond is well great!!!!
None, is the best reply so far short sweet and to the point.After 2 years I still have to explain to crews that they don`t have to count points on a circuit(residentially).Some of the old timers we have scarf at this and as long as they do the type of work they did I don`t complain.I also add that this is the NEC minimum standard and anything above and beyond is well great!!!!
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