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-   -   Can someone help me size my lighting circuit? (http://www.diychatroom.com/f18/can-someone-help-me-size-my-lighting-circuit-130465/)

 Alan 01-18-2012 09:09 AM

Can someone help me size my lighting circuit?

I'm not sure if I need 1 or two circuits for my lighting and i'm not really sure how to figure it out either. What info do I need to have in order to make this calculation?

Thanks again guys. :thumbup:

 joecaption 01-18-2012 09:17 AM

How many lights and the total wattages of the bulbs would be a start.

 Julius793 01-18-2012 09:22 AM

Quote:
 Originally Posted by joecaption How many lights and the total wattages of the bulbs would be a start.
And what size wire?

 joed 01-18-2012 05:29 PM

How many fixtures? What is the MAXIMUM wattage allowed to be installed. A 15 amp circuit can have 1800 watts. A 20 amp circuit can have 2400 watts.

 jws3 01-18-2012 06:11 PM

I wonder why ALL circuits aren't simply 20A

Would be far simpler than messing around with wimpy 15A 14g nonsense.

If I had to build another house I'd have no 15A circuits. Why save pennies? Doesn't seem worth it in this day of increased power usage.

 Alan 01-18-2012 09:34 PM

so for the sake of argument, I have 10 6" can lights ( a couple will be smaller than that) and they are what, 75 W max each?

Then my wife picked out these other 4 funky pendant lights that she likes, i'm going to say they're 100W max

Then add in the range hood 4x20W halogens = 80W and the fan motor is 190W

that's 750 + 400 +270 = 1420

I'm easily under the 1800 W range, but I have to add in some kind of under cabinet lighting as well, which I haven't decided on yet either (open to suggestions) I've got roughly 12feet of upper cabinets that need under cabinet lighting put on them. Any ideas on what range of wattage i'd be looking at for those?

Might be a safe bet to say that a 20A circuit will light up the whole place and if I decide to add something in there after the wire is in, I won't be kickin myself. :)

 joed 01-18-2012 10:30 PM

Do you think everything will be on at the same time? I suppose you should allow for that. But the breaker will not trip as soon as it hits 1800 watts. It would probably run for 20 minutes or more at 1800 watts.

In Canada lighting is only permitted on 15 amp circuits.

 Alan 01-18-2012 11:08 PM

I don't think so. I doubt my wife will even use the range hood. She thinks it's too loud. I'm always turning it on for her. :furious:

I know the bar lights won't be used at the same time as the kitchen lights.

I'm located in california, so if somebody can chime in whether 20A lighting is OK, that would be appreciated. :)

 Julius793 01-19-2012 01:17 AM

Quote:
 Originally Posted by Alan I don't think so. I doubt my wife will even use the range hood. She thinks it's too loud. I'm always turning it on for her. :furious: I know the bar lights won't be used at the same time as the kitchen lights. I'm located in california, so if somebody can chime in whether 20A lighting is OK, that would be appreciated. :)
What powers the range hood itself??

 darlingm 01-19-2012 01:40 AM

Someone could say I'm off here, but I think there's also a requirement that a 15A lighting circuit can only cover 600 sq ft, and 20A can only cover 800 sq ft.

I'm not sure how the exact language reads on calculating square footage, and whether you're allowed to break it up by code like this, but I just installed two lighting circuits and broke the lights into two sets where if one of the circuits went dark, you could still navigate through the house somewhat effectively. More or less, I started by throwing the bedrooms on one circuit, then started alternating through the rest of the house. Probably overkill, lighting circuits shouldn't trip, but still easy to do...

You may already know this, but I guess one of the main reasons to use the range hood is to get the carbon monoxide out. That is, if your stove/range is natural gas. (Monoxide is the more dangerous one.) Carbon monoxide isn't one of the main byproducts of burning natural gas, but it is one of them. Apparently newer studies are showing that stoves & ranges kick out extremely high levels of carbon monoxide when they start, and stay at elevated levels while running. I always thought it was just to vent heat & steam out...

 joed 01-19-2012 07:44 AM

California also has weird energy saving codes that require florescent lighting in kitchens I think.

 SD515 01-19-2012 08:14 AM

Quote:
 Originally Posted by darlingm (Post 827550) Someone could say I'm off here, but I think there's also a requirement that a 15A lighting circuit can only cover 600 sq ft, and 20A can only cover 800 sq ft.
The NEC doesn't put a square foot limitation on circuits. Square footage is used for load calculations.

 Alan 01-19-2012 09:01 AM

Quote:
 Originally Posted by Julius793 (Post 827543) What powers the range hood itself??