Today I just put in the conduit and wiring for my table saw due to
arrive in a day or so. I have 4 outlets along the wall, chest high,
5-6 feet between each box. My question is how to hook up the wires in
the main box. I have a separate 200 amp box for the garage/shop.
Inside are 2 empty ganged circuit breakers, unused, in addition to
the 120VAC breakers. They used to run a compressor and a welder per
the previous owner. The ganged circuit breakers have a screw on each
one to connect the wire. For 220VAC, do I run the two "hot" wires to
each one of the screws? The neutral, white, goes to the ground strip,
I could find that easily. And does it matter red/black wires, which
goes to which part of the socket? (except the neutral/ground).
And, if I had a good meter, I would use it, but I'm at my
"summer"house where this is all happening. And 1700 miles is too far
to go back and pick it up!
Thanks to all for any help!
If you use a 2 pole breaker you connect one hot to each side, that is
240v. The ground wire goes to the grounding bus and the 3d prong of
the receptacle. If there is a neutral load (4 prong plug) you hook the
white to the neutral bus. If this is the main panel the neutral and
ground bus will be the same. A sub panel has the neutral isolated from
the can and the ground bus.
Your assumptions are correct. Red and black are interchangable with
respect to which side of the socket or which of the poles of the
circuit breaker they connect to. Just connect one to each of the two
screws on one of the ganged breakers, like you said. For a tablesaw
the white wire is probably not going to be used and doesn't need to
connect to the socket in any way. I'd just coil it up in the box
behind the socket and stick a wire nut on the end.
By the way, you said there are four outlets. Are these all 240V or
some 120V as well? If mixed, did you run a separate wire or wires for
the 120V outlets so they can be on their own circuit(s), or are you
planning to piggyback onto the 220V? If so, you'll need the neutral
for those recepticles.
You didn't specifically mention the green grounding wire, but a proper
connection is important. Whether it is bare or green, it should be
connected to the grounding buss in the distribution panel and to the
appropriate point on the receptacle, including to the metal outlet box
if you are using one.
If you have only three wires (Black, Red & White) you should use the Black &
Red for your Hot leads (interchangeable) and the white as the ground.
Running a 220v piece of equipment without grounding it is dangerous. I
recommend using green tape or colored marker to change the end of the white
wire green so in the future others will know it is a ground.
If you have a 200v machine that has a 110v light or other 110v accessory,
you will need a 4th wire (black, red, white & green or bare). The white and
one of the hot leads is for the 110v load and the green/bare is to ground
Not correct in any respect. First off, if he has only three wires, they will
almost certainly be black, white, and bare -- not black, red, and white. If he
has black, red, and white, he also has a fourth conductor, which will be bare
Second, white is NEVER to be used for ground. White is neutral, and bare/green
Better to use the bare (or greeen) wire which is already there.
As noted above, if he has black, white, and red, he already has the 4th
conductor as well.
Doug Miller (alphageek at milmac dot com)
Long time lurker, first time poster here.
Doug, I've watched you give out crappy electrical advice for quite some
time, and I think it's time I give you a little schoolin'.
First of all, TomH's post was pretty much spot on. So your bit about
"not correct in any respect" is horse hockey.
You haven't done much wiring, have you? In a perfect world, the three
wires are black, red, and g/b. How often do you think that happens?
All the time? Most of the time? SOME of the time?
I've run into situations contstantly where you get black, red, and
white. Hell, I just bought some 12/3 that had black, white, and green.
Only a fool relies on wire colors to tell him what that load that wire
carries or doesn't carry.
White gets used for ground all the freakin' time...especially in the
situation TomH describes. Granted, in the electrical codes, white
SHOULD be neutral, and G/B SHOULD be ground. But if you got a
red/black/white, would you suggest hooking a different color to the
ground? Honestly...would you?
The bottom line is that you can get a multi-meter for $14 at a hardware
store. If you know how to use it, do so. If you don't, get a damn
electrician to hook you up.
Doug Miller wrote:
You should return to Lurking. Doug was correct, you are quite incorrect.
Actually, it is a violation of the NEC to use a conductor that is
not green, bare or green/gray as a grounding conductor.
The white conductor (aka grounded conductor, aka neutral conductor)
may be used as a current-carrying conductor, if it is appropriately
marked at both ends, but it may never, under any circumstances be
used as a grounding conductor. Period.
As an electrician, I did plenty of wiring, both new installs and
retrofit work. I no case did I, nor any electrician I worked with
advocate the use of, nor use the grouded conductor as a grounding
In no case would such work ever be passed by an inspector.
And, btw, 12-3 romex has been sold w/g (with ground) since the
Type SJ, right? Can't be used in wall anyway.
Further deponent sayeth not.
No, white _MUST_ be neutral and GREEN/Bare/Gray&Green _MUST_ be
ground. The NEC doesn't use the word _SHOULD_.
I, and any electrician worth his salt, would replace the wiring with
the correct gauge and number of conductors.
Take your own advice, fella, and have an electrician do your electrical
work. You owe it to your family, friends and the next owner of your
You obviously have me confused with Toller -- and you should school yourself
first before you try to school me.
No, it wasn't, and if you knew anything about wiring you would have seen the
same errors I did.
It's pretty clear that you haven't done *any* wiring -- you haven't any idea
what the colors are in a normal cable.
Didn't read my post too carefully, did you? I never said you couldn't have
black, red, and white -- just that you wouldn't have *only* black, red, and
white, without having a grounding conductor as well.
No, you didn't. You bought 12/2 with ground.
Nobody's talking about load here...
Doing so is a Code violation.
Wrong. In the NEC, white MUST be neutral, and green/bare MUST be ground. They
are flatly prohibited from being used for anything else.
Yes, I would. I'd suggest attaching the green or bare wire that is *also*
present to the ground.
Sounds like you should be calling the electrician before you touch anything.
Doug Miller (alphageek at milmac dot com)
Bullshit. Where in Florida have you done 100% of your wiring, Dougie?
I say Florida, but you can substitute any location where all the houses
have been built since 1970. You know how many times I've hauled wire
out to replace an outlet, only to find just a black, a red, and a
white? Or a two blacks and a white? Your problem is you define normal
as "what I've seen that's been rewired since 1970." Come to an older
city...pull some outlets out. Tell me what you find.
Read my reply above. You'll see it all the time.
You're as ignorant as I thought.
Yes it is. And it's done every second of every day of every year. And
there's so many local variations on the NEC, and those variations
change with such frequency, that I would not be at all surprised one
day to pull a purple wire out of a wall. And guess what? Inspectors
never see it.
You are correct, but you missed my point. And you also missed the
point where I agreed with Tom H where he said to change the color of
both ends of the wire to indicate it was now being used as a ground.
Have you ever heard of a little city by a lake called Chicago? It's in
the midwest...Google maps can probably help you. Just type
C*H*I*C*A*G*O into the text box, upper/lower case doesn't matter, but
leave out the asterisks. You might have to add "Illinois."
This is important because, in Chicago, they don't follow the NEC.
They're like hundreds and thousands of other municipalities in the
country who don't.
In Chicago, Romex is expressly verboten. (That's German for
"forbidden," Doug.) You are required to use conduit for everything in
Chicago. Everything there above a certain guage is stranded wire, too.
So you see, Doug, you can pull all manner of colors out of an outlet
Because although the CEC requires white to be neutral and green to be
ground, not all rewiring work done in Chicago is done by lisenced
(read: union) electricians. Sometimes you get some homeowner who
doesn't know much about codes, but he knows how to run a pair of
pliers, and he does his own rewiring.
And you are certainly permitted, by code, the Chicago Electrical Code,
not the NEC, which they don't follow in Chicago, to "change the color"
of a wire by covering it with tape, of the appropriate color, at ALL
switches, junctions, etc. Green can only be used for ground. But a
white wire can be "relabled" ground with simple tape, which is just
what our friend Tom H suggested he do.
So the point is, over the years, and by that I mean roughly a hundred,
give or take, all manner of wire has been used in houses. During the
time America has been wiring houses, the codes weren't always
particularly uniform. And there are still several states which have
not, and probably will not, adopt the NEC. What was code at the time,
in that locality...well...who knows...
So I'll ask again...where in Florida have you done all your work?
No, Detroit is right here. The CEC was developed entirely separately from
the NEC...they have nothing to do with each other.
In some respects, the NEC is tighter, and in many respects far, far looser.
Different animals all together.
I can confirm that the Chicago code bears little-to-no resemblance to the NEC.
And, I've been in an argument with an electrical inspector there, over
code-compliance. And *won*.
The Chicago code is obnoxiously restrictive in some respects -- even the
_telephone_ wiring has to be in conduit! And, it is a *swamp* to wade through.
Some section says "you can't do this", but something else, many _pages_ away
says "that section doesn't apply *IF* these conditions are met". BUT there
is yet another section that says "that exemption doesn't apply under _these_
conditions". etc., etc., ad nauseum.
And they're _all_ 'backward' references -- there's nothing at the "you can't
do this" section that contains _any_ reference to those other 'special case'
situations. Gotta read *everything* to have any idea of what you can/cannot
do in any specific situation.
When using DC I believe the NEC now requires black and white, black being
hot (positive) as usual and white being the negative or ground. Not
typically found in any AC wiring but when doing solar electric it's a pet
peave of the AHJ in SW Colorado.....
Now back to our regularly scheduled bickering
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