More controversy, maximum recept on a 20 amp circuit

Status
Not open for further replies.
B

brother

Senior Member
Location
"I have learned, in whatsoever STATE I am, therewi
Well been reading up on my electrical, and I know this topic has been debated/discussed here many of times. However in this 'Master Electricians Review" book, it states that a maximum of 10 duplex receptacles (180 VA) are permitted on a 20 amp circuit in other than dwelling occupancies.

You take 20 * 80% = 16 amps (table 210.24 210.23(A) )
180/120=1.5 amps
16 / 1.5 = 10.667

dwellings are unlimited according to them.

What do you think?? I didnt think the 210.23 NEC 2008 80% rule had to be counted in on the actuall calculation of how many receptacles on a 20 amp breaker. Realistically speaking, This article NEC 2008 , 210.23 seems to be more of an 'UNENFORCEBLE' rule for the people/clients plugging things in these receptacles.

Have I been thinking wrong on this one and not counting how many duplex receptacles on a branch circuit??
 
I agree. The recepts are not considered continuous loads. So comp @ 100%

20x120=2400/180=13.3

13 peceptacles on a 20a circuit.
 
brother said:
Have I been thinking wrong on this one and not counting how many duplex receptacles on a branch circuit??
Click to expand...

YES - IMO

The residential no-holds-barred approach is out-dated, and IMO dangerous. Some consideration should be taken in designing circuits if the NEC as a minimum is not mandating it - you should pick a number.... Based on your gut feeling..... :rolleyes: A "home office" would need a few circuits, a hallway is only going to need a GP from someplace else...

That said - 180VA is also a silly and low number in some commercial situations. The NEC has no idea what people are plugging in any more than we do. I have guys stop at 10 per circuit all the time. (And by LOCAL code - all commercial is 20's) WHY? 10 is an easy round number, offers a few more watts per outlet per circuit, and if in a bind I can add 3 more by code.... I also make other circuits available to each area - not just one. Run a round-house all the way through... For the most part, most of my customers when I was on my own, or with the companies that I work for now, did not hire us because we were cheap - they want quality, reliable and often up-grade-able work.

this 'Master Electricians Review" book, it states that a maximum of 10 duplex receptacles (180 VA) are permitted on a 20 amp circuit in other than dwelling occupancies.

You take 20 * 80% = 16 amps (table 210.24 210.23(A) )
180/120=1.5 amps
16 / 1.5 = 10.667

dwellings are unlimited according to them.
Click to expand...

Now that I have that off my chest - I think your book is wrong... The maximum number of outlets permitted on 15- and 20-ampere branch circuits is 10 and 13 outlets, respectively.
 
e57 said:
Sure - Yes - I have a feeling you're going to say that the OCP will operate for sure... That you can trust a breaker will limit the current on the circuit after the 50th time it tripped?
Click to expand...
Same arguments can be made for even single-receptacle circuits.
 
e57 said:
YES - IMO

The residential no-holds-barred approach is out-dated, and IMO dangerous. Some consideration should be taken in designing circuits if the NEC as a minimum is not mandating it - you should pick a number.... Based on your gut feeling..... :rolleyes: A "home office" would need a few circuits, a hallway is only going to need a GP from someplace else...

That said - 180VA is also a silly and low number in some commercial situations. The NEC has no idea what people are plugging in any more than we do. I have guys stop at 10 per circuit all the time. (And by LOCAL code - all commercial is 20's) WHY? 10 is an easy round number, offers a few more watts per outlet per circuit, and if in a bind I can add 3 more by code.... I also make other circuits available to each area - not just one. Run a round-house all the way through... For the most part, most of my customers when I was on my own, or with the companies that I work for now, did not hire us because we were cheap - they want quality, reliable and often up-grade-able work.



Now that I have that off my chest - I think your book is wrong... The maximum number of outlets permitted on 15- and 20-ampere branch circuits is 10 and 13 outlets, respectively.
Click to expand...


Where does the code say that?

I could write a book and say that the maximum number is 5 and 7.

I don't see anyplace in the code where it limits the number of outlets on ANY circuit??

If I wanted to put 30 bedroom outlets on a circuit in a dwelling unit so I could only use 1 AFCI I could.

The same applies to commercial.

Is it good practice, no.

Is it allowed by code, yes.
 
e57 said:
Sure - Yes - I have a feeling you're going to say that the OCP will operate for sure... That you can trust a breaker will limit the current on the circuit after the 50th time it tripped?
Click to expand...


If it has tripped that many times, you have other issues to deal with.

I do not see how in dwellings, this issue leads to a dangerous situation. Remember the NEC is a minimum code document for safety. How an installer chooses to do his installation above the NEC is a design feature.
 
I guess our opening count is determined by our local inspectors.
16 receps on a 20 amp circuit
13 lights on a 15 amp circuit

Comercial
6 openings on a 20 amp circuit.
 
The State 0f TN is presently adopting an ammendment to the 2008 Code stating that on AFCI Circuits (which they also ammended to be the same as 2002 Code) there shall be no more than 10 outlets on a 15 amp circuit, and 12 outlets on a 20 amp circuit. Effecvtive 1/28/09 that will be part of the State Code.
 
augie47 said:
The State 0f TN is presently adopting an ammendment to the 2008 Code stating that on AFCI Circuits (which they also ammended to be the same as 2002 Code) there shall be no more than 10 outlets on a 15 amp circuit, and 12 outlets on a 20 amp circuit. Effecvtive 1/28/09 that will be part of the State Code.
Click to expand...

so if I have an 8' plugmold that has outlet spacing every 6" I would need 2 circuits?
 
This sort of ties in with the AFCI issues.
Perhaps more important the number of receptacles is their placement. Have more.

The code minimum (resi) builder won't do them if the code doesn't require it; but anyone who can envision actually using athat space can see where one or two more will eliminate the need for extension cords. eg: Any bedroom longer than X feet gets 2 rather than placing them for the six foot rule.
 
augie47 said:
The State 0f TN is presently adopting an ammendment to the 2008 Code stating that on AFCI Circuits (which they also ammended to be the same as 2002 Code) there shall be no more than 10 outlets on a 15 amp circuit, and 12 outlets on a 20 amp circuit. Effecvtive 1/28/09 that will be part of the State Code.
Click to expand...

They are probably doing this to reduce false tripping on the arc fault, long runs tend to produce more leakage current, just like ground fault breakers will false trip on long runs. Maybe that's why I've never had a problem with the arc faults, I rarely do more than two bedrooms on one circuit, with the master on a dedicated circuit. I put the smokes on a 15 amp dedicated arc fault circuit to comply with all outlets being arc fault protected. (interconnected detectors)
 
aftershock said:
I guess our opening count is determined by our local inspectors.
16 receps on a 20 amp circuit
13 lights on a 15 amp circuit

Comercial
6 openings on a 20 amp circuit.
Click to expand...

This amazes me. One has to wonder about the logic that the local inspector uses to arrive at these limits. :-?:)

What ever happened to "due process of law"? What legally elected body would allow an electrical inspector (note voted in to office) to make up rules, effectively side-stepping the whole legislative process? Unless those seemingly ridiculous "rules" have been passed into law, throw the bum inspector out of town. :mad:
:)
 
Where does the code say that?

I could write a book and say that the maximum number is 5 and 7.

I don't see anyplace in the code where it limits the number of outlets on ANY circuit??

If I wanted to put 30 bedroom outlets on a circuit in a dwelling unit so I could only use 1 AFCI I could.

The same applies to commercial.

Is it good practice, no.

Is it allowed by code, yes.
Click to expand...


Back in the Day....( In 220-3(b)(9) 2002 NEC ) Receptacles were calculated at 180 volt amperees. 100% for receptacles and 125% for continuous loads per table 220.13. Multioutlet assemblies were addressed in 220.3 (B)(8).

Man I miss some of the codes from earlier days!
 
Rockyd said:
Back in the Day....( In 220-3(b)(9) 2002 NEC ) Receptacles were calculated at 180 volt amperees. 100% for receptacles and 125% for continuous loads per table 220.13. Multioutlet assemblies were addressed in 220.3 (B)(8).

Man I miss some of the codes from earlier days!
Click to expand...

Rocky, go back and read 220-3(b)(10), it is identical to the now 220.14(J), nothing has changed, there was no limit in residential even then.

Roger
 
hillbilly1 said:
They are probably doing this to reduce false tripping on the arc fault, long runs tend to produce more leakage current, just like ground fault breakers will false trip on long runs. Maybe that's why I've never had a problem with the arc faults, I rarely do more than two bedrooms on one circuit, with the master on a dedicated circuit. I put the smokes on a 15 amp dedicated arc fault circuit to comply with all outlets being arc fault protected. (interconnected detectors)
Click to expand...
Properly installed wiring will have no leakage current no matter how long the runs are.
 
Roger,

Will take my crow straight out of the oven!

Resi 3va per square...

Rocky, go back and read 220-3(b)(10), it is identical to the now 220.14(J), nothing has changed, there was no limit in residential even then.

Too lazy to go get the 08 out of the car the first time.


Crow.jpg
 
wbalsam1 said:
This amazes me. One has to wonder about the logic that the local inspector uses to arrive at these limits. :-?:)

What ever happened to "due process of law"? What legally elected body would allow an electrical inspector (note voted in to office) to make up rules, effectively side-stepping the whole legislative process? Unless those seemingly ridiculous "rules" have been passed into law, throw the bum inspector out of town. :mad:
:)
Click to expand...

I should have said Local inspection dept. or AHJ.
 
Status
Not open for further replies.
Top