120v versus 240v for a saw

[Wade Lippman]

I know this has been covered ad nauseum, but this is a bit different.

I was about to install a 240v-20a line for a new saw and DC, when I found the breaker I needed (a 20-20 quad; they have 20-30s everywhere) wasn't available locally.

I thought about it and wonder if a 20a multiwire circuit wouldn't work just as well, and maybe be more versatile. The saw I am looking at is 15a (120v) and the DC is 12a, so with both going there wouldn't be any more voltage drop than with a 240v circuit. (Presumably the advantage of 240v circuit is the reduced voltage drop.)

Am I overlooking something?

[Morgans]

I'm not sure you made your question clear. You want to do what?

[Phisherman]

You may need to so go to an electrical shop to the breaker you need. There is less current needed with 240v (P = I * E * power factor) and the motors will operate more effeciently with smoother start/stops.

[Erik Ahrens]

Define a "quad" breaker.

Erik

[ATP]

Four half space breakers that fit in two spaces, which gives you two 240 V circuits. The inner and outer pair are linked together.

[Gfretwell]

The only way I have seen this done was with the old style SqD QO double breakers (2 big handles) and handle ties. Wouldn't it be easier (cheaper) to double up a couple of 120v circuits and free up 2 slots?

[Wade Lippman]

Unfortunately, everything else is already doubled up. Siemens has a full line of this kind of stuff, but the one I need is not available locally.

[Doug Miller]

"Not available locally" is a bit unlikely, unless you live someplace that's

*really* rural. :-) My guess is you haven't looked in the right places yet. Three things to try:

1. Ace Hardware often has a much wider selection than Lowe's, Home Depot, etc. when it comes to "specialty" breakers such as this. TruValu Hardware is worth a try, too.
2. If you're in, or anywhere near, a city of decent size, there should be an electrical supply house somewhere not too far away. Maybe even a Grainger store. If they don't have it, they should be able to get it.
3. If all else fails, try online sources such as Dale Electric I've bought from these guys several times, good prices, prompt shipping, never any problems.

-- Doug Miller (alphageek at milmac dot com)

How come we choose from just two people to run for president and 50 for Miss America?

[Gfretwell]

You are probably overdue for an upgrade. A sub panel is one option.

[ATP]

Do you still have the diagrams on the inside of the panel door? Some panels do not allow every full breaker space to be used as a twin. Quite often 20 full size spaces will only support 30 breakers, and they tell you which ones can be twinned. In addition, the older panels had less space for the wire, so they were marginal at full capacity from a practical, wire management standpoint.