Max receptacles per 20 amp circuit

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jxofaltrds

Senior Member
Location
Mike P. Columbus Ohio
Occupation
ESI
I thought the intent was to divide the 3 VA per sq ft by 1800 to determine the minimum number of gen ltg BC then evenly distribute the number of receptacles required by 210.52 amongst them a evenly as possible,

but I do not have a code book with me????

But agreeded there is no limit on the number of recepticals on a gen ltg BC.


yes no??

I agree.

You can NOT run the whole home (recpts) on one circuit.
I have argued that point but no one here (in Ohio) agrees with me.

IMHO the no limit was so that I or the homeowner could add another outlet without adding additional circuits to a specific area (room).
 

Volta

Senior Member
Location
Columbus, Ohio
I thought the intent was to divide the 3 VA per sq ft by 1800 to determine the minimum number of gen ltg BC then evenly distribute the number of receptacles required by 210.52 amongst them a evenly as possible,

but I do not have a code book with me????

But agreeded there is no limit on the number of recepticals on a gen ltg BC.


yes no??

It seems that 210.11(B) only requires the spaces and load capacity to be installed to the branch-circuit panelboard(s), not the actual circuits.

The "overcurrent devices and circuits shall be required to be installed only to serve the connected load." So we need only provide as many circuits as needed to supply hard-wired lampholders or luminaires, and the gen-purpose receptacles need not be counted as additional load (until a load is connected, anyway :roll:).

I agree.

You can NOT run the whole home (recpts) on one circuit.
I have argued that point but no one here (in Ohio) agrees with me.

IMHO the no limit was so that I or the homeowner could add another outlet without adding additional circuits to a specific area (room).

Do you agree that "there is no limit on the number of recepticals on a gen ltg BC", but you feel that multiple circuits are needed? How many?
How do you interpret 210.11(B)?
 

charlie b

Moderator
Staff member
Location
Seattle, WA
Occupation
Electrical Engineer
You can NOT run the whole home (recpts) on one circuit.
Well, you could, but the whole home would not run very well. The owner would probably see a lot of tripped breakers (sorry, I mean a lot of trips of that one breaker). But the NEC does not care about happy homeowners.


I have a limit I impose on receptacles per circuit. Several limits, actually, with the number varying with the type of building and the function of the circuit. Receptacles in the areas of a lab building in which lab experiments take place will have one limit. The office areas of the same building will have a different limit. Kitchen areas, corridors, outdoor areas, and classroom areas will each have a different limit. But these are all design choices I have made, not code requirements I am following.
 

zappy

Senior Member
Location
CA.
Well, you could, but the whole home would not run very well. The owner would probably see a lot of tripped breakers (sorry, I mean a lot of trips of that one breaker). But the NEC does not care about happy homeowners.

I have a limit I impose on receptacles per circuit. Several limits, actually, with the number varying with the type of building and the function of the circuit. Receptacles in the areas of a lab building in which lab experiments take place will have one limit. The office areas of the same building will have a different limit. Kitchen areas, corridors, outdoor areas, and classroom areas will each have a different limit. But these are all design choices I have made, not code requirements I am following.

Why doesn't the NEC care about a breaker always tripping, and a wire that keep being overloaded? Sounds kinda like a hazard to me?:confused:
 

jxofaltrds

Senior Member
Location
Mike P. Columbus Ohio
Occupation
ESI
I thought I read above 1800SF.

Anyway if the house was 1200SF or less you might be able to use one 15AMP circuit or one 20AMP circuit if under 1600 SF.

But if you where trying to meet the minimum you probably would use switched recpt. instead of ceiling lights.

Then I would look at 210.21(B)(2) and the table.

So now we might have to lower my above numbers to 960SF for one 15AMP circuit and 1280SF for one 20AMP circuit.
 

mlnk

Senior Member
In our area you need one general use circuit for every 500 square feet or portion thereof of floor area. For a 1600 SF house that is 4 circuits. On each circuit, of course, you can install as many outlets as you want. The reasoning here is: 3 watts per square foot. Max of 1440 on a 1800 watt circuit (15 amps) 1440 divided by 3 = 480 SF. If you are running 20 amp circuits (which I think is foolish), it is 1920 /3 = 640 SF per circuit. Some AHJs say 500 for 15 amp, 600 for 20 amp. Some say 500 for whatever. I find it hard to believe that your AHJ says you can run a whole house on one general use circuit! Get it in writing!
 

roger

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Staff member
Location
Fl
Occupation
Electrician
I find it hard to believe that your AHJ says you can run a whole house on one general use circuit! Get it in writing!
The AHJ doesn't come into play unless they have amended the NEC.

Roger
 

Volta

Senior Member
Location
Columbus, Ohio
I thought I read above 1800SF.

Anyway if the house was 1200SF or less you might be able to use one 15AMP circuit or one 20AMP circuit if under 1600 SF.

But if you where trying to meet the minimum you probably would use switched recpt. instead of ceiling lights.

Then I would look at 210.21(B)(2) and the table.

So now we might have to lower my above numbers to 960SF for one 15AMP circuit and 1280SF for one 20AMP circuit.

So I'm trying to figure out your method and if I consider 1200 sq ft @ 3 va per, I get 30 amps @ 120 volts, before demand factor. Not 15 amp.

How do you figure this?

And what do you mean with the permissible receptacle ratings of 210.21(B)(2)?
 

jxofaltrds

Senior Member
Location
Mike P. Columbus Ohio
Occupation
ESI
So I'm trying to figure out your method and if I consider 1200 sq ft @ 3 va per, I get 30 amps @ 120 volts, before demand factor. Not 15 amp.

How do you figure this?

I was using an estimate on the feeder load to make my example. Not a good example.

I have used your #'s and agree with them but have lost that argument. I tried to use Annex D for my argument (pp 1344 handbook) to show that, as in your calculations, 2 circuits would be needed.

My previous cals were to show that we have to figure that load for our service so why does it not apply to the branch circuits.
 

Volta

Senior Member
Location
Columbus, Ohio
. . . My previous cals were to show that we have to figure that load for our service so why does it not apply to the branch circuits.

Because we simply have to provide capacity, in both ampacity and spaces, up to and including the branch-circuit panelboard(s). We need only provide circuits to serve the connected load.

If there are luminaires in the kitchen, bathroom, hallway, stairway, garage and storage space, and we want to put the general-purpose receptacles on that circuit also, what section forbids that? Receptacles are not connected loads.

Switched receptacles are not lighting outlets, rather they are permitted to be installed in lieu of lighting outlets 210.70 (A)(1) Exc. 1.
 

stars13bars2

Senior Member
Going by 3va/sq. ft. a 15 amp circuit would be good for 600 sq. ft. and a 20 amp circuit would be good for 800 sq. ft.. An 1800 sq. ft. house would only require three 15 amp general purpose lighting circuits to meet code minimum, but would not be very practicle. The code is not concerned about convenience as much as safety, and therefore does not care how many times you reset the breaker.
 

mlnk

Senior Member
To ROGER: The AHJ has plenty to say about it because they interpret the Code. Every electrical installation has an AHJ. The AHJ is the bridge between the NEC and the jobsite. So the AHJ saying, or writing 500 SF or 600 , or 800 per circuit is very important. I still say find me an AHJ who will let you use one circuit for gen use for a 1600 SF house....Silence...They all have rules. Either a rule of thumb like 500 SF. Or a number based on 80% loading, or 100%. Some AHJs will say we go strictly by the NEC...then they show up on the job site and start interpreting.. because the NEC is a book of general guidelines- without interp there can be no inspection,
 

neilR

Member
The load for each circuit shall be based from the NEC 2008 Art. 210.23 (Permissible Loads), In no case shall the load exceed the branch-circuit ampere rating. An individual branch circuit shall be permitted to supply any load for which it is rated.
 

iwire

Moderator
Staff member
Location
Massachusetts
To ROGER: The AHJ has plenty to say about it because they interpret the Code.

No, the AHJ can only legally enforce what has been adopted as code in that area. They cannot change or make up the rules at will any more than a cop can.
 

roger

Moderator
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Location
Fl
Occupation
Electrician
To ROGER: The AHJ has plenty to say about it because they interpret the Code.
And they have to give us a formal set of rules to follow, in my case the NEC with a few amendments.

Every electrical installation has an AHJ.
and here that is the state of NC, not an individual inspector.
The AHJ is the bridge between the NEC and the jobsite.
No they're not, it's my code book and the inspector
So the AHJ saying, or writing 500 SF or 600 , or 800 per circuit is very important.
No, article 220 saying what it says is very important.
I still say find me an AHJ who will let you use one circuit for gen use for a 1600 SF house....Silence...
If an inspector (or AHJ) allowed this they would need some additional training.
They all have rules. Either a rule of thumb like 500 SF. Or a number based on 80% loading, or 100%. Some AHJs will say we go strictly by the NEC...then they show up on the job site and start interpreting.. because the NEC is a book of general guidelines- without interp there can be no inspection,
And here they only enforce the NC State electrical code (the NEC with some amendments) they will not try to make up their own rules.

Roger
 
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mlnk

Senior Member
I agree the inspector can make up rules no more than a cop can...try telling a cop what to do or not to do and you will soon need bail money or really good health insurance. In the case of the inspector you will just need a suitcase full of money.
I agree that it is a good idea to learn the rules. But they do not cover every jobsite situation. For example: # of cables in a drilled hole, the use of bushings, torquing of connections, twisting of wires before using wire nuts, sunlight resistance of PVC, side entry in exterior boxes. use of self grounding receptacles... I am sure forum members can think up a few more.
 
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480sparky

Senior Member
Location
Iowegia
.......I am sure forum members can think up a few more.


Wire nuts in panels. 100' max raceway runs. Splices in LBs. Required anti-oxidant. 120/240 and 120/208 must be Blk/Red/Blu and 480/277 must be Brn/Orn/Yel. 3-ways required in stairways.
 

iwire

Moderator
Staff member
Location
Massachusetts
I agree the inspector can make up rules no more than a cop can...try telling a cop what to do or not to do and you will soon need bail money or really good health insurance. In the case of the inspector you will just need a suitcase full of money.
I agree that it is a good idea to learn the rules. But they do not cover every jobsite situation. For example: # of cables in a drilled hole, the use of bushings, torquing of connections, twisting of wires before using wire nuts, sunlight resistance of PVC, side entry in exterior boxes. use of self grounding receptacles... I am sure forum members can think up a few more.

Not saying I always refuse to do things not required but I sure do not roll over and do anything they ask.
 
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