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Would you put any 15 amp circuits in new construction if it was your house?

Would you put any 15 amp circuits in new construction if it was your house?


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Old 01-24-11, 07:14 AM
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Would you put any 15 amp circuits in new construction if it was your house?

Hello.

I am building a new house and I have got mixed opinions whether or not to put any 15 amp circuits in the house.

Some say go no lower than 20 amps but others say 15 amps are Ok as long as it serves lighting only.

I realize the 20 amp wire will cost a little more, but is it cheap insurance?

What would you do?

Thanks!!!
 
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Old 01-24-11, 08:07 AM
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I posted this in another thread a few days ago....
Had a neighbor back in VA (Master Electrician who owned his own company)who said when he built his own home, ALL the outlets would be 20A..just in case he ever wanted or needed to use a high draw device. (Think miter saw or air compressor, or even a couple of space heaters in an emergency)

Don't forget your outlets and such will also cost a few dollars more...

I'm no electrical Pro...but I would think using a large panel and isolating rooms as much as possible would really be something to consider. So when you need to shut off a bedroom or bath for something, you don't take down the office and living room as well. I'd run a couple of different circuits to the garage as well.

Also..I'd probably stick with 15A for lighting. With CFLs and LEDs taking over..there will be much less demand on those circuits.
 
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Old 01-24-11, 09:14 AM
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You're probably not going to save any money on wire unless you're doing this work without a permit and inspection. Minimum wire size for all circuits is now 12 gauge where it used to be that 14 ga. was allowable in lighting circuits. The code allows using the regular 15 amp receptacles in a circuit on a 20 amp breaker according to my #1 electrical subcontractor.
 
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Old 01-24-11, 11:08 AM
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it's rather wasteful and more labor intensive to wire wall sconces, door lights, smoke alarms, door bells, etc with 12.
 
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Old 01-24-11, 11:29 AM
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Minimum wire size for all circuits is now 12 gauge where it used to be that 14 ga. was allowable in lighting circuits.
Tldoug. what do you base that on? If from 2011 NEC remember most areas are on 2002 or 2005 or 2008. Any wiring only needs be done to current local codes and will be grandfathered in almost all cases.
 

Last edited by ray2047; 01-24-11 at 01:59 PM.
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Old 01-24-11, 01:50 PM
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Originally Posted by ncseattle View Post
Some say go no lower than 20 amps but others say 15 amps are Ok as long as it serves lighting only.
I have installed several 15A circuits in my own house including lighting, a dedicated freezer receptacle, smoke detector circuit, garage door opener and garage lighting, dishwasher, gas furnace, maybe some others too. The code only requires 20A circuits in the kitchen, bath and laundry. There are other places where it makes sense to install 20A circuits, but also many circuits like those I listed where the extra capacity is simply wasted given the specs of the appliances.

I realize the 20 amp wire will cost a little more, but is it cheap insurance?
For the circuits where it is reasonable you would want more capacity, then go ahead and do 20A. I think it is reasonable to go 20A circuits in general living spaces where you will be using carpet cleaning machines, home entertainment stuff, maybe the occasional space heater. Pulling 20A circuits to your garage and outdoor receptacles makes good sense too as you are likely to use large machines in those areas.
 
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Old 01-24-11, 02:17 PM
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The branch circuits added in my house are all 12 AWG with the exception of a smoke detector circuit which is 14 AWG since I figured it will never be added to, or over capacity. I do have 12 AWG with 15A breakers on the whirlpool tub and the furnace since those are dedicated circuits with loads below 12 amps.

I have some remaining 15A/14AWG circuits from former owners' remodeling, but they will all be upgraded to 20A/12AWG eventually as we re-remodel.

That said, when you do everything in 12AWG you complicate issues like box fill. For example you have to think about what exactly you can fit in a 2x3 box both from a fill and a practicality perspective. Since 14AWG is smaller it's notably easier to work with.

Another reason that I've mentioned before is that when you wire your own house with conduit and THHN, it makes sense financially to buy only rolls of 12AWG rather than both 12&14 and have unknown reel ends of each when you're done. So once you're putting in all 12AWG, it makes little sense to use 15A breakers on general purpose circuits.
 
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Old 01-24-11, 05:22 PM
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Originally Posted by ArgMeMatey View Post
... So once you're putting in all 12AWG, it makes little sense to use 15A breakers on general purpose circuits.
One factor is the cost of the 20-amp receptacles that will be required. A quick check of Lowe's web site suggests that 10-packs of plain white receptacles are about 25% more for 20-amp versus 15-amp. Still, at about $5 per 10-pack, it should be less than $100 difference for even a pretty big house.
 
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Old 01-24-11, 05:27 PM
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Even with the 20 amp circuits if there is two or more places to plug into you can use 15 amp slotted devices. They are still rated for 20 amp feed-thru.

I couldn' t tell you the last time I saw a cord with a 20 amp end.
 
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Old 01-24-11, 06:04 PM
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Originally Posted by pcboss View Post
Even with the 20 amp circuits if there is two or more places to plug into you can use 15 amp slotted devices. They are still rated for 20 amp feed-thru.
Don't buy the cheesy 29c receptacles as you will be replacing them in a week. Hubbell 20A commercial receptacles are $1.66 at my supply house, and I have them all over my house.

Originally Posted by pcboss View Post
I couldn' t tell you the last time I saw a cord with a 20 amp end.
I have three of them next to me right now, and I'm in mybedroom,
 
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Old 01-24-11, 06:15 PM
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I'm no electrician, but I would stick to using the 14 on any lights and circuits that are allowed. I know a lot of people are putting 12 in all the outlets even though they don't have to, but it is a waste......Besides, ever try to wrap that forth or fifth # 12 wire together and then have to smash it into some 4 gang box.....14 is much more forgiving.
 
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Old 01-24-11, 06:20 PM
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Originally Posted by pcboss I couldn' t tell you the last time I saw a cord with a 20 amp end.

Originally Posted by Justin Smith I have three of them next to me right now, and I'm in my bedroom,

What do you have in your bedroom that needs( 3) 20 amp cords...a portable nuclear reactor?
 
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Old 01-25-11, 07:57 AM
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Originally Posted by bish80 View Post
What do you have in your bedroom that needs( 3) 20 amp cords...a portable nuclear reactor?
I am guessing he means he has 20A receptacles unless his bedroom is in a commercial kitchen or a carpentry shop. Or maybe he has a vibrating waterbed with a heater?
 
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Old 01-25-11, 01:25 PM
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Originally Posted by bish80 View Post
What do you have in your bedroom that needs( 3) 20 amp cords...a portable nuclear reactor?
1) clock radio
2)netbook
3)spare
Every outlet in my bedroom, bathroom, kitchen, living room, outside, must I go on?, as welll as alot of other outlets is 20A.
 

Last edited by Justin Smith; 01-25-11 at 01:29 PM. Reason: spellin
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Old 01-25-11, 02:15 PM
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Originally Posted by Justin Smith View Post
1) clock radio
2)netbook
3)spare
Every outlet in my bedroom, bathroom, kitchen, living room, outside, must I go on?, as welll as alot of other outlets is 20A.
that would be quite the clock radio to have a 20amp cordset!
 
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Old 01-25-11, 03:38 PM
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To anyone reading this lets be clear despite what Justin chooses to do you do not need 20a receptacles or 20 amp extension cords on general purpose circuits.

They may be needed for special purpose equipment like some commercial space heaters, welders, compressors and maybe a very old Xerox machine. If none of these are commonly used in your bedroom your ok.

Legitimate reasons might be a 120v window AC or 120v portable space heaters but best practice they should be on dedicated circuit and you should never use an extension cord. Note even these will normally have 15 amp plugs. A 20a receptacle would be needed in the rare case of a simplex receptacle on a 20 amp circuit. None of these special circuits are really general purpose which is what this thread is about.

Above references US codes. Canadian may vary.
 
 

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