Conduit - PVC or EMT

[Steve DeMars]

Conduit and boxes . . . EMT and metal boxes? PVC conduit and PVC boxes? PVC conduit & metal boxes?

Will be covering all walls & ceiling in shop with 1/2" plywood. Would use

3/4", but here in Louisiana building materials are high and scarce.

Will insulate walls & ceiling also.Want to surface mount electrical . . . lights, receptacles, switches, etc . .

What have you guys used? What works best & is there much difference in cost. Have done a lot of residential electrical using ROMEX.

Never fooled with conduit except in an industrial setting . . . . I was an instrumentation technician ( PetroChem).

Any suggestions as to material or layout appreciated . . . Shop is 20' X 22' with 10' ceilings . . . . Will be running 115vac & 220vac receptacles.

Shop has it's own meter with 200amp service. I want to surface mount EVERYTHING . . . . .

Thanks in advance, Steve

[todd]

If you use PVC, make sure you ground the pipes. All of that electricity running through there will generate a lot of static and the next thing you know, you'll have an explosion. OK, j/k.

Here in the Chicago area, we don't get much of a choice. You're pretty much using EMT for everything. It just so happens I was looking at some PVC conduit at Lowes today. (For some reason, at least at the ones I visited this weekend, Home Depot and Menards don't carry it). I get why it might be used outdoors, but I'm unclear why it would be used in place of EMT indoors. To be honest, I don't remember where they fell in terms of price. To me, for indoor use, it seems that EMT is the way to go. One consideration is the ability to bend EMT as needed. You could probably get the desired effect with the application of enough PVC elbows, but now we're just adding more $$. If it was me (and imagining I actually had the choice), I would use EMT.

todd

[Steve DeMars]

Thanks . . . I have a conduit bender . . .

Steve

[Doug Miller]

Much cheaper, and easier to cut. And it can be field-bent with a heat gun.

[todd]

I just looked up the online price at Lowes. 1/2" EMT is $1.87. 1/2" PVC is $3.22. For larger sizes, EMT is more expensive, but AFAIK, most conduit in peoples' homes is 1/2". Something tells me that bending PVC might be a little trickier than bending EMT.

todd

[Bugs]

Better check your local building & electrical codes. Locations subject to accident or abrasion may require EMT or even rigid steel conduit. It would be too bad to get it all installed and have the electrical inspector red tag the work. Bugs

[Mike Marlow]

Just my opinion but EMT and metal. It's a bit more work, but you carry ground via the conduit and it saves wire in the conduit. I'm not really sure how the costs compare these days. PVC can add up quickly once you start throwing all the miscellaneous stuff into the shopping cart.

All irrelevant to your question. Either system will work. Your choice.

[Art Greenberg]

I used PVC conduit and boxes. Ran everything in 3/4-inch, which made pulling the wires a bit easier and allowed me to use larger gauge and/or more circuits in a run. I used off-the-shelf elbows and offsets, rather than bending my own for the most part. When I did need to modify a bend, I just soaked the part in hot water for a few minutes.

Check with your local AHJ to be sure PVC is acceptable in your area, and for a wood shop application. Regardless of which material you choose, make sure you compute and verify fill on every run, and for every box. And use the right kind of wire.

[Teamcasa]

"Steve DeMars"

snip

I used EMT and flex. If was going to do it over again, .... EMT and flex.

Dave

[mac davis]

basic info: Check local codes first... it's a real pain to have them find out you're doing it and make you tear it out and do it "their way"... Even worse if they red tag it and stop progress OR tearing it out until they "resolve" it... DAMHIKT....

mac

Please remove splinters before emailing

[Phisherman]

I used Romex wiring for my shop, seven circuits. One circuit is 220. I installed all the boxes, switches flush mount with the drywall. However, one wall is poured concrete so there I used surface mount tracks and low profile boxes, fastened with concrete (blue) screws and construction adhesive. The surface mount is a bit more expensive and doesn't look as nice, but that was my only choice if I wanted outlets on that wall. I installed my sub panel in a closet, centrally located in the shop which saves some wiring and work. Instead of the tracking you can use the conduit, but you'll have to deal with the bending and tools.

[Doug Schultz]

Is there any reason why you dont just cut holes in the plywood and sink your boxes into the wall? why run conduit on top of the wall and have the box sticking out? seems it would be cheaper to just use romex and put it in the walls just like you would do inside your house if you were using drywall.

Doug

[Scott Lurndal]

subpanel in a closet is a probable NEC violation.

scott

[Scott Lurndal]

To expand on that, it is a definite violation to put a subpanel in a clothes or coat closet. Additionally, the panel must have clear space

36 inches in front of the panel and (IIRC) 18" or 36" on either side of the panel.

scott

[Steve DeMars]

Thank you everyone for your input and suggestions . . . After reading the replies, pricing EMT and surface mount boxes, the complexity of routing and dealing with NEC . . . I have decided to wire the shop like a residence . . . just a lot more outlets ! ! !

Thanks Steve

[gfretwell]

30" wide, 36" deep, 6'7" high of clear space in front of the panel. You can start the 30" wide at either edge of the panel, it doesn't have to be centered. You can include the open closet door in your working space if it is wide enough, located in that "box" and swings open 90 degrees or greater. They are just trying to establish a safe place to stand and work while you are working in the panel.

[Mike M]

Presently in small sizes emt is much cheaper then pvc. EMT is also easier to get a good looking installation with. PVC tends to sag alot and really has a high coeffecient of expansion. If your doing surface runs look into using kindorf channel. You can put in your strut and then run all of your runs on it and planned out you can use strut spacers to avoid doing offsets to pass over other runs of pipe.

MikeM

[Mike Marlow]

Wiring with romex can certainly be easier from the stand point that you don't have to master a new skill - bending EMT, but that's about the extent of its ease. It's not a bad choice for a shop, so I'm not trying to talk you out of a romex solution, but dealing with NEC is something you do every time you run power - whether that's encased in EMT, romex, or, or, or...

[Randy Thomas]

Using emt as a ground is not a good idea, (I'm not sure if it does or doesn't meet code any longer). It tends to loose continuity causing problems with the circuits. The MGM Grand fire in Las Vegas was caused by an emt ground that lost continuity in the deli. Things heated up, and all hell broke loose.

The Electircal Engineers I used to work with, were aware of several other major instances of fires caused by over heated conduit grounded circuits, and wouldn't spec or design for it, because it is a known problem and they didn't want the liability.