ECN Forum Forums Code Related Discussion NEC & other Code issues How many receptacles per branch?

Indeed a good thread

mdsmith,
i just wished for points of view, there are many romex jockies that seperate lighting for the genny interface

I,m not an electrician just an maintance guy building a house. Trying to figure my circuits. On a 15 amp circuit roughly 1440 watt max. On a 20 amp 1920 watts max. keep light and plug seperate due to if one blows not left in dark. How many watts is a ceiling fan, refrigerator, dishwasher. Can I run the whole house as a 20 amp 12 ga wire. Why must I used 14 ga 15 amp. Does GFI need own circuit or can I branch.. I got a friend that works for the power company that will do the job, I.m just trying to understand some of it.

brownbag,
just keep readin' here....

I dont think that I realized the far reaching effects my orginal question has on most of the wiring that is done. It seems to me that some thing this big, that affects a design so much, should be reference and defined in the code with a clear and concise section. Any takers on that?

The NEC does not deal with design issues (supposedly). On that basis, you shouldn't expect the code to change.

As far as residential wiring is concerned, if you could show how this is a safety related issue, keeping in mind that there are many years of experiance dealing with house wiring in the code, then you would have some basis for getting this changed in the NEC. I don't think it is any big deal.

Housewiring is such a cut-throat business, those that do it usually have to stick to the bare minimum in order to get the job, otherwise they'd price themselves out of the market.

Just for grins , why don't you submit a proposal for the 2005 NEC?

I'm confused. Some of you are saying 10 receptacles on a 20 amp circuit and some are saying 13 (in commercial occupancies). 1999 NEC table 220-13 shows that the first 10 kVA may be calculated at 100% which would allow 13 receptacles on a 20 amp circuit. 220-21(b)(2) requires that the maximum cord and plug connected load on a 20 amp circuit to be no more than 16 amps, which is 80%. This would allow 10 receptacles on a 20 amp circuit. It seems to me that these two references are in conflict with other. Can anyone clarify this for me? (By the way, most of the local inspectors in my area ask for no more than 7 receptacles on one 20 amp circuit.) As usual this is a great discussion. Even with almost 30 years in the trade I learn something here almost every day.

WireWrestler,

ref: 1999 NEC

Table 220-13 is demand factors the code allows to be applied in sizing feeders and or services for nondwelling receptacle loads, not for determining the number of receptacles per branch circuit. For this, you need to look at 220-3(b)(9), (the handbook has an excellent explanation of the article). Use 180VA per strap > 180VA/120V=1.5A per strap > 20A/1.5A per strap = 13.333 straps > 13 straps or devices.

Article 210-21(b)(2), the way I read it, is for the maximum cord-and plug-connected load for each receptacle, (not branch circuit), where the branch circuit has more than one receptacle on it. We as designers and installers lack control in meeting this requirement. It seems to me, this would be imposed on the building occupants after the installation is complete and in use.

[This message has been edited by mdsmith (edited 01-08-2002).]

The is an alleged rationale behind most codes. I don't know how old 220.3(b)(10) is. My gut is that a few extra residential receptacles vs. extention cords was, at one time, the intent.

mdsmith
Thanks, the muddy water is getting clearer.
WireWrestler

With regards to the number of duplexes for residential,I would check with the local authority or who ever issued the permit.Many times these local authorities have supplements to the NEC that are enforced.Also check to see what year of the NEC they are using.

Chris