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View Full Version : 20 amp versus 15 amp


rstallard
Feb 10, 2005, 11:32 AM
Hi all,

I would like to use 20 amp circuit breakers, 12 gauge wire, and 20 amp "commercial" outlets in my basement finishing job (for all the wiring you would normally service with 15 amp breakers). I know it's a little more expensive, but I like the idea of being able to expand when I need to, and I hear it saves a little energy using bigger wire. I'm putting no more than 10 outlets per circuit.

Will this cause any problems? (BTW, 20 amp requires 12 gauge per local code).

Thank you!

Rich

labman
Feb 10, 2005, 01:23 PM
I don't see any problem, except code may not allow 5 outlets on one circuit. As far as the wiring goes, it shouldn't make any difference. However, no matter how may outlets you have, you can't use much more than about 2000 watts at any one time. It is OK to have much more than that plugged in, as long as you aren't using everything at once. It is much easier to not have to unplug your saw when you switch to using a drill. I have the outlets for my workbench on the same circuit as some of my outside outlets thinking I can't work inside and outside at the same time. I also have one of those 2 into 6 adapters so I can plug in a 20 watt light with my washer and gas dryer.

tkrussell
Feb 11, 2005, 07:33 AM
No, using #12 for all the basement outlet wiring will be no problem. #12 is being used much more to give homeowners the benefit of a 20 amp circuit. If you were to compare the additional cost of using #12 over #14 , you would find the cost negligible.
The savings of using larger wire is also negligible when dealing with such small wire in short distances. Using a next size larger than required does reap energy savings by virture of reducing the impedance and DC resistance of the circuit, however, it can be measurable in larger loaded circuits, say 200 amp continuous load, typical of commercial or industrial applications.Dont expect to see any change in your electric bill.
Thou the maximum of 10 outlets on your circuit is a great standard, it does not apply to residential installations. It applies to all other installations, and is calculated by allowing 180 VA per outlet ,which totals 1800 VA. A 20 amp circuit can only be loaded 80%,or 16 amps,or 1920 VA. So 1800 VA is the most allowed to be connected to a 20 amp circuit,therefore 10 outlets.Residential is calculated differently, too long to explain here


Keep in mind any outlets in unfinished basement must be GFI protected.

Hope this helps.

Kevin

lionfoxx
Feb 21, 2005, 09:22 AM
I just bought my first house, and it is wired with 12, we were replacing some plugs and noticed the new plugs would not fit the quick connect wire, it stated use only 14 on quick connect and 12 on the wire bolts.

Upon thinking about this, I remembered the switch box only has 20 amp and 30 amp breakers, I know 2 bedrooms and a bathroom and a hall way were all on one breaker which I though odd, but my friend said it would not be a problem since I had 20 amp breakers, but I need to make sure all my plugs are 20 amp and not 15 amp. He had concern that a 15 amp plug might burn up before the breaker blew, but the then again he said he didn't know what you could plug in one outlet to draw that, and if you were running one item in one room and another in another room that most likely it would be OK, because the 15 amps on each plug would be lower, just the breaker would allow up to 20 amps on the whole loop before anything blew.

When I swapped 2 of them out I noticed that 15amps is what was in there, and they look like the original plugs, but its hard to say. Is it a problem to use 15 amp plugs or should I buy the 20 amp models?

Thanks, LFX> :D

labman
Feb 21, 2005, 01:07 PM
Some of the heavier power tools or window air conditioners may draw over 15 amps. As long as you don't expect to be using any of them, I wouldn't bother to change the plugs.