Studying Residential Lighting Wiring Practices

9209 Views 62 Replies 27 Participants Last post by  janagyjr
I'm studying residential lighting wiring practices at the moment (it's chapter 8 in Electrical Wiring Residential, 16th Edition, Ray C. Mullins) and the author is speaking of some Rules of Thumb (caps and emphasis his, not mine) and I'm wondering if he's just pulling words out of his backside.

Some of the methods he's speaking of he titles "Outlets per Circuit Method" and the "per square foot method" (basically using load calculations as per the NEC). Are there really any such Rules of Thumb methods, or is it just the NEC "per square foot method"?

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The per square foot method is real and used as a minimum number of general circuits in a home.

There are also rules of thumb, they are not in the NEC and vary by place and electrician. For example a rule of thumb for me is 10- 12 outlets per circuit, lights seperate from outlets ect but nowhere is this specific in the code, its simply a preference to make it easier.

220/221

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The rule of thumb I was taught (almost 40 years ago) was, one 15A, general lighting/receptacle circuit per 500 sq ft.

Still seems about right.

janagyjr

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It's 600 sq ft for 15A receptacles, 800 sq ft for 20A (according to my textbook).

Thanks, keeping that in mind. One of the tasks in the chapter is to draw in receptacle and lighting outlets on a set of example drawings that are included with the book. So far so good according to my instructor (though I kind of went nuts in the garage, the instructions say to put whatever I want within the rules set by the NEC).

B4T

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I learned rule of thumb where (10) receptacles and or lighting outlets per (15) amp. circuit..

That is always a hard thing to figure without knowing the load involved..

janagyjr

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That's what I figured but thought I'd ask folks whom have actually done this sort of work outside of the textbook.

RIVETER

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I'm studying residential lighting wiring practices at the moment (it's chapter 8 in Electrical Wiring Residential, 16th Edition, Ray C. Mullins) and the author is speaking of some Rules of Thumb (caps and emphasis his, not mine) and I'm wondering if he's just pulling words out of his backside.

Some of the methods he's speaking of he titles "Outlets per Circuit Method" and the "per square foot method" (basically using load calculations as per the NEC). Are there really any such Rules of Thumb methods, or is it just the NEC "per square foot method"?

Asking on another forum to get widest possible aggregate of responses.
I am not aware of any "rules of thumb" in the industry. The NEC IS the code, even if it is the "minimum" required. "Rules of thumb" won't hack it...in a court of law... if a problem occurs as a result of your work.

Cletis

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I learned rule of thumb where (10) receptacles and or lighting outlets per (15) amp. circuit..

That is always a hard thing to figure without knowing the load involved..
It is bad design to put lighting on with receptacles

Cletis

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Drinking..

You really need to stop drinking and posting at the same time.. :no:
It's not really the drinking, it's when I go off my med's for a bit. Bare with me..

480sparky

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RIVETER

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It's not really the drinking, it's when I go off my med's for a bit. Bare with me..
Whether you are right, or wrong...I will never "bare" with you.

Cletis

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....

Just one electrician's opinion.

Thanks, but.......... no.
You don't have to bare with me. It's your life. But, why is it good design ever to put receptacles with lighting ??

Magnettica

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You don't have to bare with me. It's your life. But, why is it good design ever to put receptacles with lighting ??

Yeah, that makes no sense at all. :whistling2:

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....

RIVETER

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You don't have to bare with me. It's your life. But, why is it good design ever to put receptacles with lighting ??

When there isn't a fixture in the center of the ceiling in the room...maybe.

480sparky

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......... why is it good design ever to put receptacles with lighting ??

Why is it a 'bad' design to do so?

Cletis

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VF

You know, when people vacuum they dim all the lights on the circuit

Magnettica

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Why is it a 'bad' design to do so?
Cheap dimmer interference with the cable/ satellite reception for one. Electrical noise.

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