Question for Bruce: I sgree that **SEPERATE** breakers are bad but how
about running the same setup (2 opposite side hots, neutral, and ground)
off a **220** breaker? Overload on circuit 'A' will trip that side and
the other side 'B'.

In my case, I have a single person shop where I may run a 240 volt table
saw, but can't run the router at the same time. Or I may run the shop
vac on one circuit and the 3hp router on the other circuit.

As background, the lights are on seperate circuits (I hate finding the
breaker box in the dark after an oops!), plus there are dedicated 240
circuits for things like the shared circuit for the welder and 5hp
planer, the dust collector gets it's own, etc.

Bruce L. Bergman wrote:

On Sat, 09 Jul 2005 16:35:06 GMT, (Doug White)
wrote:


I finally got a new service hookup done for the house, and there is a
nice new breaker panel in the corner of the shop with the lathe & mill.
Both run off 110V.

The way my old shop was wired, I had both sides of the 220V & a neutral
run to some quad outlet boxes. That way I could wire the boxes as 220V,
or split things up and have 2 duplex outlets, each on a separate breaker.
I never used the 220V option, but having dual 20 amp circuits was nice.
I'd like to do something similar now.


Not that safe - When you run a 220V outlet, it has to have both
sides of the circuit on a breaker with a common trip handle-tie.
Otherwise you can trip out one side and the 220V motor stops - but the
outlet is still 120V hot on one side to ground. Can cause you some
serious unwanted excitement when you grab that "dead" receptacle.

I'd strongly suggest running a separate 3/4" conduit (flex or EMT)
with a 4-wire #8 THHN Copper circuit (2 Hots, Neutral, Ground) to a
separate 4S steel box on the wall. You can always change out the
receptacle and the breaker feeding it to whatever you need at the
moment, but that's enough for a 50-amp welder plug.

And you run the neutral in the 4-wire circuit back to the panel just
in case you ever want to install a 4-wire receptacle and run a mixed
120/240V load - you aren't allowed to run ANY incidental neutral loads
(like lights, controls or fans) back on the safety ground wire.


The trick is how to run the wires in a clean fashion. The basement is
somewhat finished, and there is wainscotting running around about 3 feet
up the wall. It is made of tongue & groove stained pine, nailed to 2x3
studs and contains some insulation. At the bottom, there is a metal
baseboard for hot water heating. I can run a conduit down from the
breaker panel through the top of the wainscotting, which is capped with a
1 1/2" thick stained & varnished moulding. From there, I need to go
about 8 feet horizontally. That's where things get tricky.

There's no way to cleanly go horizontally through the studs in the
wainscotting, and the tongue & groove paneling is nailed together well
enough that it would make a real mess of things if I tried to take a
piece out.

Big Snip

You can not run Romex cable exposed in an occupied space, period.
The attic and crawl space are not occupied spaces, garages and
finished basements with easy access are.

For a Romex circuit that terminates in the garage or an occupied
space you can slide a piece of flexible conduit over it as armor where
it comes out of the wall, but don't plan on pulling it all the way
through. The outer sheath gets hung up on everything.

Make it easy on yourself - don't fight ripping he walls open, just
run EMT tubing on the surface. Practice with the bender so the bends
are all neat and pretty, clamp it down well with straps to the studs
or joists so it wont move, and then paint it to match the room. The
paint will make it all but disappear.

It's a stupid basement, not your front entry hall... :-0


Also, does anyone know if there is a table for running Romex in conduit?
I'd like to be able to use a big enough conduit for two cables for future
expansion, and I doubt I can physically get two runs of 12x3+ground
through a 1/2" piece of EMT. Even if I could, I don't expect it's to
code. I could run individual wires (THHN), but then I'd need a junction
box someplace to switch to Romex for the rest of the run. The problem is
that I only have a hickie for 1/2", and would need to get a bigger one
for making the offset to get from the top of the wainscotting up & into
the breaker panel cleanly. I only need to go about 2 feet, and I suppose
I could use plastic conduit.


Would you STOP with the thinking "Romex, Romex, Romex" already? ^_^

The old rules still apply - You can still go all the way from the
panel to the loads with regular wires in conduit, and not 'turn it
into Romex' at any point along the way. Conduit is a much better way
of doing it, because if you put enough pipe into the walls (including
a few spare boxes in strategic places) you'll never have to open the
walls up ever again.

With conduit, if it goes open or you need a heavier circuit there
you open the boxes and repull the wires, done. When Romex goes bad in
the walls it's like Ben Grimm says: "It's Hammerin' Time!" ;-)

There really isn't a fill table for Romex in pipe, because the
sheath and paper filler throws the wire area cross section charts
right out the window. As a practical matter, one 12-2 or 12-3 Romex
in 1/2" pipe is full.

You can get 10 #12 THHN wires into 1/2" conduit - that is enough for
6 circuits (3-wire) and a #12 ground wire. (Do NOT trust the pipe as
a grounding conductor, always run a green wire.)

You can get 3 #8 THHN and a #12 ground in 1/2" conduit for the 50A
welder receptacle if you are careful. (The #12 ground wire puts it
just a hair over "legal fill" but it's also not a current carrying
conductor - gray area.)

Or go buy yourself a 3/4" EMT bender - they're $35 new at The Borg
(Home Depot or Lowe's). Or go find one at a garage sale for $1. They
are very handy, because they also bend 1/2" Rigid conduit or gas/water
pipe. Though building inspectors might get nervous if they see a
saddle bend in a gas pipe going around an obstruction...

PVC Plastic conduit could be used, but is usually reserved for
outdoor work and concrete embedment in and under the slab. I really
would not suggest using it exposed indoors because it burns (and makes
lots of smoke), and you don't need to add any more fire load.

Run a separate EMT or flex run from a box on each basement wall up
and over to the sub-panel, from each support column in the 'middle of
the room' over to the sub-panel, and blank off the boxes that you
aren't using yet.

When you decide to add that planer in the middle of the shop, or a
new bench grinder in the corner, pop the cover off one of those
'spare' boxes and run whatever size wires you need.

If there are more than four bends (360-degrees worth) in any run you
have to stop at a pullbox along the way - or you'll have a heck of a
fight getting the fishtape and the wires through later. Again, it's a
basement - if there's a pullbox blank cover poking through the
ceiling, who the heck cares? Paint it white.

-- Bruce --