DIYbanter - View Single Post - When to use 15A vs. 20A circuits (and #14 vs #12 wire)?

From: "Terry"

"Jeffrey J. Kosowsky" wrote in message
...

We are about to install several new circuits as we upgrade the
electrical systems in this very old house.

Any difference in price between #12 an #14 wire should be minimal; e.g.. a
few cents per foot. Breakers prob. identical price.

Also; if you have a situation where you may need more capacity than a 20 amp
circuit can handle, this might typically be a kitchen area, a suggestion.

Instead of two wire (White?Black plus ground) #12 install three wire
(White/Black/Red plus ground) #12. This will allow all the outlets on that
run or perhaps just one or two important ones to be 'split'. That is each
outlet can be wired so that the upper half of a duplex connected to one leg
of the supply and the lower half to the other leg of the supply thus
doubling the capacity of the circuit. The additional cost of the third
conductor will be small. The only other cost will be that of a two-pole
breaker in place of a single pole breaker.

It won't be small. First, any box within that circuit will probably have to be
oversized from standard, since you now have 2 additional conductors in every
box you spliced through.

You'll use more wirenuts. :-)

And the worst is - 3 wire cable in either 14 or 12 guage is almost always
exactly double the price of it's 2-wire version. Now you're paying 100% more
for the cable but getting only 33% more copper conductor. And that really
****es me off.

You'd be better off running more 2-wire circuits and putting fewer outlets on
each if extra capacity is what you're after.

Another method would be to use only 3-wire for the "homeruns" and make sure
each circuit of outlets is fed middle-of-the-run. Leave the red as a spare and
if some time in the future needs be, you can always split that circuit into 2
equal separate circuits without running 3-wire cable all over the place.