Talking to a new, young electrician today about wiring a couple rooms for me in one of my rentals.
I said that other electricians had told me that it was acceptable to wire up to 13 outlets on a 15 amp circuit – typical residential construction, NEC on Long Island, NY. They also said that the norm was to stay with 10 outlets or less on a circuit.
He got indignant and insisted that you should never wire more than 8, and said that the other electricans were ignorant (not exactly the word he used). I’m not so sure he’s right.
Any comments?
Don K.
EJG Homes Renovations – New Construction – Rentals
Replies
In my old book the rule is to figure 180VA (1.5A) per single or multiple receptacle, which works out to a max of 10 on a 15A circuit, 13 on a 20A circuit (or 9 and 12, if rounding isn't allowed).
So it sounds like they were both wrong.
This matches what I was taught. 9 for a 15 amp and 12 for a 20.George Patterson
Yeah, I'm working from the '81 code, but I think the 180VA limit may apply. There is a table that can be interpreted as saying there's no limit ("all receptacle outlets ... shall be considered as outlets for general illumination, and no additional load calculation shall be required"), but it's unclear whether it's referring to the load for an individual circuit or the whole house.But this is a typical example of how the code is screwed up -- all sorts of exceptions in section x to what's stated in section y, with minimal cross-referencing. And footnotes to tables are considered as significant as the mainline text. It's hard to say whether this is just inertia, or whether it's a conscious attempt at exclusion by obfuscation.
If your view never changes you're following the wrong leader
I don't think the code is screwed up at all. It doesn't make sense to put an absolute limit like that on anything. The 9 and 12 outlet limits to which I referred were regarded as rules of thumb when I learned them, not law. I would still follow those rules when wiring typical house circuits, but, as someone else already pointed out, you can do a lot better if you know how the circuits will be used.For example, I have two 20 amp appliance circuits in my shop. I would not hesitate to put 20 outlets on each, since it's highly unlikely that I would plug in enough stuff at one time to create a dangerous situation. On the other hand, I can trip one of those breakers by misuse of a single one of those duplex outlets. You can't write code to deal with that.George Patterson
Sensible post.
There is no limit, the 180va referred to is for commercial applications.
When I wire the areas that don't required specialized circuits, like bedrooms, dens, family rooms, etc I tend to look at the square footage rather than the number of outlets when I figure how many circuits to use.
I still generally use 15a circuits for these areas but I always ask about any heavy-draw equipment. i.e. air conditioners and space heaters being most common around here(New England) and add some 20a outlets if I think they'll be needed.
If the area will be accessible later (like 1st floor being accessible to fished wiring from an unfinished basement) then I don't worry so much about it: if someone rearranges the furniture or buys some new megawatt something and needs more power, it can be fished in easily later. But if it's NOT going to be easy, like a finished 2nd floor with a finished attic above, then I'm more careful to add some extra juice.
In a typical new home with a finished 2nd floor and unfinished attic, I usually pull up and stub in the attic an extra cable that runs right to the main panel. This has saved my butt many a time when I get called back later to install something new that hadn't been in the original plan.
It's be a total drag if the NEC started mandating limits to the number of outlets on a circuit. Some people take the 3 watts/sq.ft concept as applying room to room in circuit design. This would be a much more sensible way to mandate power requirements.
The example someone gives of the wife using an iron on a 15a bedroom circuit (rather than using the code-mandated 20a-required laundry circuit) shows why you can't plan for this stuff.
Ed
Edited 10/11/2007 7:38 am ET by edlee
I wasn't talking about the code being screwed up in the sense of having the wrong limits, but rather that it's an unintelligible document. I'm a bit surprised that no one has ever sued NFPA for producing something so poorly written and hard to understand/interpret.
If your view never changes you're following the wrong leader
For dwelling units there is no limit on the number of receptacles on a general purpose circuit.
However, some local amendments do have limits.
The 180 va/receptacle that Dan mentions is not for residences.
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Now, that's an answer I didn't expect. I'm going to ask the Kid for a code citation - after he does the job and bills me. :-)
Don K.
EJG Homes Renovations - New Construction - Rentals
Sometimes it's best to let common sense override what the code book says. Less is better. But then again it depends on how you plan to use them. Don't let the code fool you into thinking that it's what's best for you. It's the very minimum that you are allowed to do. You always have the option of doing it better.
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"I tell you, We are here on earth to fart around, and don't let anybody tell you any different." Kurt Vonnegut jr.
I'm beginning to see that codes tend NOT to be 'up to date' in terms of needs.These days, we plug a LOT more in the wall than even a decade ago. We have multiple computers, printers, monitors, plasma TVs, DVD players, playstations, phones...
That's my point. Every situation has different needs.
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"I tell you, We are here on earth to fart around, and don't let anybody tell you any different." Kurt Vonnegut jr.
http://www.youtube.com/watch?v=e5MG1ZfFiZ8&mode=related&search= Mercy now
Right. In case I wasn't clear, I was agreeing with you. ;o)
I know. I was using your reply to make my point again.
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"I tell you, We are here on earth to fart around, and don't let anybody tell you any different." Kurt Vonnegut jr.
http://www.youtube.com/watch?v=e5MG1ZfFiZ8&mode=related&search= Mercy now
Gunner-
I understand what you are saying. I wouldn't necessarily wire to the "limit", but in this situation, it's a basement with one small framed room (10x12) and a service bathroom (bowl/sink). Chances are nothing heavy will be plugged into any of these outlets. I don't always agree with codes - such as the requirements for outside outlets, home run GFI's in the bathrooms, microwave outlets, etc. Seems like they get carried away. But the point about disagreeing with codes has been well discussed around here.
My post was as much out of curiosity as anything else.
Thanks to you and all for the responses.
Don K.
EJG Homes Renovations - New Construction - Rentals
Best is when the DW is doing the ironing in the bedroom watching tv, everytime the heat element kicks on the iron, the lights dim, think the sparky ran 8 plugs & 1 light/fan combo on that 15 amp circut.
There's the NEC answer ... and the right answer. Many towns place a limit on the number of receptacles on a circuit .... or have special rules for rental properties.
When in doubt ... ask the inspector. That's what you pay him for.