I'm expanding my home workshop to include some heavier machinery, and it's time to put the workshop on its own subpanel. This is driven in particular by the need for 240V/1ph power for a new milling machine that I can't fire up until I get this work done.

My existing service:

Meter & service entry at Siemens combined panel (200A) on exterior of stucco garage wall, with only three occupied breaker slots. (Yay!) Main panel, via dual 100A breakers, feeds Siemens house-load subpanel (20/40 type, no available slots). So, for more power, I'm clearly going to need to run a new subpanel off the main panel.

Question #1

If the main panel wiring is accessible via the space between the exterior stucco wall and the interior drywall of the garage, what is the approved means of bringing a new set of THHN feeder wire (6-6-6-8) from a panel knockout to the surface of the interior drywall so that I can run it through conduit? Assume that I'm comfortable with opening up and then patching the drywall on the garage-interior side of the wall.

Put another way, here's the generalized wire path:

Main panel behind drywall, top at ~6' height ->? -> surface-mount steel junction box at ~8.5' height -> conduit -> new indoor subpanel

I think I understand what I have to do everywhere but that first couple of feet between the main panel knockout and the surface of the drywall. I'm certain that simply running loose THHN wires between the surface-mount box and the main panel breakout would be a Very Bad Thing, but I have not been able to find the appropriate section of the NEC to see what the accepted practice is in this case.

Question #2:

I am adding a new, free-standing workbench to the center of my main workshop area. I would like to put in what I believe is referred to as a pendant-type power drop from the ceiling to just above the workbench, terminated with a two-gang steel electrical box providing two duplex 20A outlets.

What are the requirements for:
* ceiling junction box type and mounting assuming it's fed via surface-mount conduit
* power cable type used between ceiling box and outlet box
* strain relief at both ends

For example, would something like McMaster-Carr part 7080k53 be appropriate cable for a pendant drop when secured at both ends with proper strain relief? (I specified 4-conductor so that each of the duplex outlets can be served off a separate 20A circuit breaker.)

Q2: Use two pulling elbows. Typically called LB's with a nipple connected the two. e.g. http://www.acehardwareoutlet.com/%28...aspx?SKU=31934

You don't need the junction box at the top. Just use the LB pulling elbows at transitions.

You can use Sealtite (the same stuff your AC unit has), you can use offsets. You can use a preformed elbow combined with an pulling elbow. The latter may be the best way to go.

Q2:
I am having a hard time understanding this question. I think I can offer a substitute and that's an extension reel. I've used that for the exact situation. A hand tool power drop over a free standing table.

Retractable power reel:

http://www.arizonatools.com/tools/re...FVlM5Qod33G07Q

For a cord that could get yanked on, there is a cable grip that's used. e.g. Strain Relief Grips - Strain Relief - Electrical : Grainger Industrial Supply There are also drop grips.

You probably need a 6 conductor cable. With 4, you end up with a shared neutral. Besides you may want to have this outlet GFCI protected and a shared neutral won't work unless implemented at the sub-panel.

Try to make yourself a bit clearer.

If it's just a cord hanging down, then you have to make sure that the conduit isn't supporting it and a metal box may be more appropriate. Similar to ceiling fan support.

Q2: Use two pulling elbows. Typically called LB's with a nipple connected the two. e.g. CANTEX 5133665U BODY CONDUIT PVC LB 1"

You don't need the junction box at the top. Just use the LB pulling elbows at transitions.

You can use Sealtite (the same stuff your AC unit has), you can use offsets. You can use a preformed elbow combined with an pulling elbow. The latter may be the best way to go.

Q2:
I am having a hard time understanding this question. I think I can offer a substitute and that's an extension reel. I've used that for the exact situation. A hand tool power drop over a free standing table.

For a cord that could get yanked on, there is a cable grip that's used. e.g. Strain Relief Grips - Strain Relief - Electrical : Grainger Industrial Supply There are also drop grips.

You probably need a 6 conductor cable. With 4, you end up with a shared neutral. Besides you may want to have this outlet GFCI protected and a shared neutral won't work unless implemented at the sub-panel.

Try to make yourself a bit clearer.

If it's just a cord hanging down, then you have to make sure that the conduit isn't supporting it and a metal box may be more appropriate. Similar to ceiling fan support.

That's all very helpful, thanks. Regarding Q2, the cable grips are exactly what I was looking for -- and I appreciate the suggestion to use 6-conductor cable to make it easier to GFCI-protect those outlets.

-AG