Prepping to wire the new shop

Status
Not open for further replies.

SubGuy

Administrator
Zach
So I just recently moved (locally, we bought a house) and am setting up my shop. I am running into two issues. I need to run three 220v circuits and a few 110v circuits and I don't want to run it in the walls due to not wanting to cut the drywall. I originally had big extension cables I made in the last place and put outlets directly below the main panel. This is problematic for wires running on the floor and mobile tools. I am looking into conduit. I have been researching PVC and EMT. Seems like code requires EMT on the walls. Problem is, it will take a good number of bends to get this done and a handful of conduit bodies. Problem number 1: How to get the existing power in an in-wall box into the conduit? From what I gather, a surface mount box seems to be the ticket. Wire derating causes my wire requirements to jump from a 10 to an 8AWG in order to run it in one conduit. The other option would be to two or three separate conduits. Hence problem number 2: Wiring separate conduit or one to a box them split. Then if using EMT, becomes a lot of bending and bodies to install. It's aggravating. So how did you do it? What is NEC code compliant? What works, code compliant and is economical? I also plan on adding an additional 220v circuit or two at a later date and understand conduit fill requirements and derating I would need to make it work.
 

Brogan

New User
.
All of the issues you mention are why I gave up running circuits after closing and had it done by the builder instead.

I looked into EMT in depth and the amount of work required to get the conduit from one end of the garage to the other was bad enough, never mind the cost, then transitioning to the recessed breaker panel, etc.

I don't have any answers but you seem to have a pretty good handle on it all.
 

Graywolf

Board of Directors, President
Richard
Staff member
Corporate Member
It sounds to me like your in need of one sub-panel that will take care of your transition giving you one patch area for your Sheetrock. There is no easy way to put it other than your going to have to bite the bullet one way or the other, benders are cheep and you can build your homeruns as you go. If you still have your heavy drops you can phase in your conduit runs one at a time. Just a thought.
 

Bas

Recovering tool addict
Bas
Corporate Member
I did surface mount conduit in my shop - 3/4" EMT. It's pretty cheap, much cheaper than PVC. Bending conduit is not easy though. You're not just creating 90 degree angles, you also have to offset each end slightly to fit into the conduit boxes. By day three you'll be pretty good at it, but if you then take a break for a week you're learning all over again. Plus, you'll need to cut pipe, sand/ ream the edges, attach pipes to studs etc.

As others have a suggested, a surface mount sub panel would be a good way to bring power into the shop. From there you can run conduit/ lines to each outlet. I would avoid running multiple conduits in parallel unless for very short runs. Just run multiple wires in the conduit to a junction box and split from there. Also consider running a circuit or two to the ceiling and put an outlet there. Very useful for air cleaners and mobile tools. You can add more wire to a conduit afterward, but it's not easy. If you think you may want to add another 220V circuit later, it would not be a bad idea to run the wire now and save yourself some big headaches.

In retrospect, it would have been faster and cheaper to cut a trench in the drywall, run the wires through the studs, and then patch/ tape/ mud/ paint.
 

Gofor

Mark
Corporate Member
. If you are worried about conduit fill, realize you can run a common ground for all the circuits in a conduit, as long as that wire is sized to carry the maximum of any of the circuits. That could reduce the amount of wires in a given conduit. (As always, may want to run this by the inspector first, but it is okay by the NEC). I am planning to do the same, with multiple 20v circuits in the same conduit, but am going to use just one ground. My conduit will run along the top plate, with the outlets dropping down for the outlets.

Why are you having to derate the wires? As for derating, my understanding is that the wire size, breakers, and outlet ratings already take into account the 10% derating (i.e. you can run a full 20 amps on a #12 wire 110v outlet as long as you have a 20A rated outlet. The 10% derating is already considered in the manufacture of the wires, outlet, etc. so you don't have to figure on only 18A load.)

Also, even though in the past, the EMT conduit could be used as ground, NEC now requires a ground wire to be run in the conduit, as well as all appliance boxes to be grounded individually to the ground wire, so you may want to pick up a pack of screws if the boxes don't have them.

If you don't want to get into the hassle of bending the tubing, there is always the flex conduit. Plus is you save the money for the tubing bender and the hassle, but the downside is that it is a real pain to cut.

Go
 

McRabbet

Rob
Corporate Member
While it is not cheap, you may want to consider using metal surface raceway which allows everything to be mounted on the walls; fittings are made for inside and outside corners and multiple circuits can be run side-by-side. 120V and 240V outlets can be mounted wherever desired. It is commonly used in industrial settings (when I worked for EPA, we used it in laboratory settings along benchtops). Here is a link to just one source of Wiremold 4000 series raceway. The big box stores also carry smaller versions of Wiremold with surface mount outlet boxes and corner fittings. JMTC
 

SubGuy

Administrator
Zach
Well I walked the attic space above the garage, there is enough room (barely, have to crawl over ducting) to pull it from there. I am going with Romex and call it a day. I think for the time invested, effort invested and money invested, it's just best to deal with the loose insulation. Originally, I hadn't considered the prospect as the main box is on the opposite side of the attic access and blocked by the room. Turns out I will be able to get in there at least one way if not two. So I guess this was simply a thought exercise due to lack of on-site inspection. Next, on to the install and from there the duct collection design and install.
 

SubGuy

Administrator
Zach
Well after a Sunday of miserable attic crawling. I got the wires run and outlets installed. Awaiting an opportune time to kill the main of the house and I will be off to DC solutions. Thanks for all the food for thought guys.
 
Status
Not open for further replies.

Premier Sponsor

Our Sponsors

LATEST FOR SALE LISTINGS

Top