I know this subject has probably been hashed out many times but I bring it up again because somebody asked me why there is no limit on the number of outlets per circuit that can be installed in residential. I told them because there isn't much of a load. Then I was asked how many I put on a circuit and why. I told them I go with the so called 80% rule for commercial/industrial which is 1.5VA per outlet which figures out to be 10 on a 15A circuit and 13 on a 20A circuit. I also told them that the amount of circuits is figured out by multiplying 3VA a square foot for general lighting and then there is some mandatory ones required by article 210. So inquiring minds want to know what the average electrician puts on a circuit and why. Thanks for your time.
outlets per circuit in residential
- Thread starter elecmen
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jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
1.5VA or 180 VA? Makes a difference.
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jumper
Senior Member
- Location
- 3 Hr 2 Min from Winged Horses
True, but OP asks what is your general rule, if any.
jetlag
Senior Member
- Location
- Eatonton, Georgia
I like to figure 600 sq ft for 15 amp and 800 sq ft for 20 amp
3va per sq ft x 600 = 1800 va for 15 amp (15a x 120 v = 1800 va)
3va per sq ft x 800 = 2400 va for 20 amp (20a x 120 v =2400 va)
That is the best way to divide the outlets the most evenly , with the spacing by code the number of outlets varies a little but usually is 12 for 15 amp and 15 for 20 a . You can put as many as you want extra in the same space , that doesnt cause people to use more current . But if you increase the area for the circuit , the required outlets will be more and that puts to many on the circuit . There are those that love to argue this , saying if 3 15 amp circuits are required in a house , they can run a seperate 15 amp to 2 of the outlets and then put all the others on one circuit . And as far as I know that is not against the code .. Do you want that in your house or evenly devided by the sq ft like I do ? I go above the code though, I use the above method for 20 receptacles only, it iis suppose to cover the lighting load also , for that I figure again with more 15 amp circuits for the lights
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electricmanscott
Senior Member
- Location
- Boston, MA
There is no general rule that I use. I look at the situation at hand and go from there.
- Location
- Massachusetts
Same here. Not every situation is the same.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
In that case, it's my answer, too.Best answer that this thread will see.
Okay, to generalize, besides the usual kitchen/laundry/bath requirements, I almost always run separate 15a lighting/fan circuits and either 15a or 20a receptacle circuits, depending on room usage and area covered.
- Location
- Simi Valley, CA
Best answer that this thread will see.
That will be the best one, but soon we'll have, "I do it the way I do it and it's the only way to do it and if you don't do it the way i do it, you're wrong. Idiots.":grin:
Of course I could be wrong.:roll:
I like others, use the general rule of thumb of 10-12 per circuit, but like others said it might depend on the situation. I have 10 receptacles in my family room and only two of them are ever used on a regular basis.
readydave8
re member
- Location
- Clarkesville, Georgia
- Occupation
- electrician
I try to keep bedrooms on their own circuit, usually not much difference in load between small and large bedroom. Unless it's a high end house.
Jim W in Tampa
Senior Member
- Location
- Tampa Florida
I agree depends on situation. Usually i put master bedroom on its own (simply last person you want unhappy) bedroom 2 and 3 on another circuit along with perhaps a hall light on either one. That is for a normal size 3 bd 2 bath 1200 sq ft home . I would never wire based on the 3 watts per sq ft idea as that is far too low. Use your own judgement when you hit the high end homes that pay you far more. If your bidding track homes you just cant afford to give them the best and win. Think about the loads in a teens bedroom and you will know what to allow.Give you a clue back in the 60's i only had a box fan ,a ceiling light and a B and W tv. Not the same anymore.
jetlag
Senior Member
- Location
- Eatonton, Georgia
I dont use the 3 watts per sq ft either, for the 1200 sq ft you mentioned I would use 1200 x3 = 3600 for the receipts , That would be 2 20 amp circuits at 2400 watts each for recipts. I would figure 3 watts again for the lights 1200 x3 = 3600 so I would have 2 15 a circuits @1800 watts , now I would devide that as evenly as possible to keep part of a room from being on a different circuit . I often have to add more circuits to do that .
my total for the house is 4800 + 3600 = 8400 watts , not the 3600 that is required by code for both lights and recepts :grin:
The 3va per sq. ft. wouldn't keep the recessed lights on in many houses. I always count the lighting loads up and run in enough circuits so if all the lights are on, they stay on. Receptacles go on another circuit, except bedrooms. Unfortunately this is not a requirement (in residential) I have been in multi million dollar houses where the EC did not do this and "surprise" the kids use all the lights at once, until the breaker trips, I guess they couldn't do simple math.
Like others said "look at the situation". In a house you can easily under wire if you are not careful, it would still be "code compliant" but it will only make for an angry home owner. .
Like others said "look at the situation". In a house you can easily under wire if you are not careful, it would still be "code compliant" but it will only make for an angry home owner. .
Jim W in Tampa
Senior Member
- Location
- Tampa Florida
I never seperated lights and receptacles but would take any large lighting like several cans or chandeliers into consideration as they might all be on at same time for a party. So they might end up on 2 circuits easily just to cover kitchen and dining room lights. Also must look at what size lamps i might be installing 25 watters in chandelier and they replace with 40 , same thing with cans. Bottom line is breakers better be able to hold or customer will be on you. With high prices for copper and then arcfaults it would take some serious planning. Have not wired a new house in about 6 years so i will admit it would take some adjusting of old ways to be a winner.
Unlike commercial jobs you must do your own circuit work
Unlike commercial jobs you must do your own circuit work
Teaspoon
Senior Member
- Location
- Camden,Tn.
I don't really have a certain # of drops per circuit.
I look at the situation and go from there.I would rather over kill .It is never a problem, to have extra circuits. But an overloaded circuit is a problem.
We have a state rule on afci circuits 12 drops on 20 amp circuit. 10 drops on 15 amp.
I look at the situation and go from there.I would rather over kill .It is never a problem, to have extra circuits. But an overloaded circuit is a problem.
We have a state rule on afci circuits 12 drops on 20 amp circuit. 10 drops on 15 amp.
Jim W in Tampa
Senior Member
- Location
- Tampa Florida
Care to tell us the logic here ? Do arc fault amps not equal regular amps ? I can see that they would not want to see 20 recepts on a 15 but there numbers seem way to low.
jetlag
Senior Member
- Location
- Eatonton, Georgia
I agree , people get the wrong idea when I try to explian how I use the 3 watts per sq ft , it is only a start point , I forgot to say I add up the can lights wattage and add more 1800 watt circuits for that . I also add the wattage up on every light circuit to be sure I have enough to pull all lights at once , same as you do :grin:
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