On Wed, Jul 1, 2009 at 9:56 AM, Mark Andy<firstname.lastname@example.org> wrote:
> On Wed, 1 Jul 2009, email@example.com wrote:
>> Thanks for the quick response.
>> I ran a 3 conductor line to the saw (red, black, and white) with a bare
>> ground wire as well.
> If this is for a 220/230/240 single phase line and its wired correctly, the
> red and black are hot (each side of the split phase or whatever you want to
> call it :-), the white is the neutral for 120vac loads, and the bare wire
> the safety ground.
> You'd wire your 220vac saw to the red & black to get the 220vac. B You'd
> a regular 110vac load to either the red/white or the black/white to get the
> 110vac from one or the other of the split phases. B You'd wire the safety
> ground to the chassis in both cases.
> This is, AFAIK (and I'm not an electrician, so you get what you pay for)
> completely within the spec & intent of the all the codes. B Its how dryers
> electric stoves work, etc.
>> mechanically, I understand how I can get the 120 outlet, but I don't
>> understand, if it's safe. B and if it is, how do I breaker the wire? (do I
>> use a common single breaker for 240 or do i use 2X 120 breakers?)
> I don't know the code here, but I would think either would work fine. B I
> imagine a common single breaker is really two breakers inside anyway, one
> for each split phase.
Check your local code. This is allowed by the NEC, and it requires
either a double pole breaker, or the two handles of single pole
breakers to be mechanically tied together (So half the 240 outlet
isn't hot.); however, many local jurisdictions don't allow it, or
allow it only under limited circumstances. I don't know what people
have against it: it's how your house is wired, after all!
>> Also, is there a "better way" to do it (the 120 outlet after the 240, or
>> the 240 after the 120?)
> Electrically it shouldn't matter at all, except maybe if you use GFCI
> outlets? B If you wanted GFCI outlets, I'd put them after the saw, but I
> no idea if that's required.
Almost certainly is. Options are a 240 GFI breaker ($$$), a regular
240 breaker, followed by the saw outlet, followed by a gfci outlet on
each 120V leg. (or just one, if that's what you really want.) It's
possible your local code requires GFCI on 240 outlets, too, so you'd
have to use a breaker to do this. (I think; haven't really thought
that hard about it.)
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