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Re: Electrical ducting

To: cak@aratar.com (Chris Kantarjiev)
Subject: Re: Electrical ducting
From: Andy Banta <Andy.Banta@Eng.Sun.COM>
Date: Tue, 23 Jan 1996 21:28:23 -0800
>OK all you guys that run conduit along the ceiling with drops - how exactly
>did you do it? 1/2" galvanized conduit with individual conductors
>pulled to a junction box above every outlet, and wire nuts and extra
>conductors going down to the box? Or did you use pre-stuffed BX (flexible
>conduit)? Or much larger conduit for the horizontal? I keep coming
>up with designs that have four or five circuits going horizontally along
>the main wall (two 20 amp tool circuits, a compressor circuit that has
>to be switched from the bench, a 20 amp circuit for the heater, plus
>lights...) and am wondering how I'm going to keep that all straight,

I don't know what you mean by "along the ceiling," but I'd probably
build a smallish box section to hide numerous runs of flexible
conduit.  Flexible conduit is far easier to play with than bending EMT
and pulling wires.  With a small box, you allow yourself the
flexibility (heh) of running more through the same box in the future.

I have stamped steel beams at the seven-foot level around my shop, and
I just strap the flex conduit to the top of that.  Out of sight,
regardless of how big a bundle is there.  For twenty amp circuits, the
12-3 prestuffed flex conduit is fine.  (The number of conductors
always seems to not include ground.  12-3 contains two hot sides and
a neutral in addition to ground (four wires: red, black, white, and
green)

>much less form conduit and pull the conductors. I don't *think* I
>can get away with a single neutral for all that, for example...

Hell no.  One neutral per an opposing pair of hot, minimum.  I have no
idea what National Electrical Code allows, but it's no more than that.

>(For people who have their compressors on 220 and switch it, how do you
>switch it? My local hardware store doesn't have anything that I recognize 
>as a 220V switch - can you just switch one branch?)

Most 220 motors don't use the neutral leg of a circuit. (Read: the
ones I have, there's no need to list exceptions).

To be quite honest, I just made sure my plumbing sealed and now leave
it "on" all the time.  It doesn't start unless pressure is drained
below the low-water limit.

While this isn't as aesthetically pleasing as a nicely located wall
switch, a fair number of shop owners I've seen just throw the breaker
on appliances they don't want running.  The breaker may wear out after
a while, but they're easily replaced.

Your message did bring up an interesting problem I ran into over the
weekend, though.  More in the next message.

andy
banta@abingdon.snapple.com

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