EMT?

[Sumboodie]

I just closed on a 30x42 shop with apartment and the wiring is a mess.

The building is insulated and finished. A combo of OSB and drywall, depending on where. Short of tearing walls down, I'm going to need to surface mount conduit to run wiring.

I need to redo the lighting, as right now it's fed off a 15 amp circuit that also powers the outlets in at least 1 side of teh building, possibly more. I had an air compressor trip the breaker and I was in the dark!
Plan to run lights and door openers on it's own 15 or 20 amp circuit.

Also need to add in a few 50 amp outlets for welder.

And sort out the apartment. As far as I know they took the 20 amp 240v feed for the dryer and are spliced off that feeding the whole apartment. I figured this out when I had a vaccuum running and the dryer and the breaker tripped.
Yeah... very possible to have the dryer, a microwave, the fridge, lights, TV, ceiling fan, etc on all at once!
I think a dryer is supposed to be 30amp 240v on it's own, so the 20 amp isn't correct at all.


ANYHOW, is 1/2" EMT the most common to use for this?

I'm thinking to surface mount a metal box over top of the breaker panel, feed wiring from the panel (in wall flush mount) into that box and conduit from there to wherever it needs to go. Will run along the ceiling I suppose.

 

[racecougar]

Size your EMT based on the number and size of conductors in any particular run.

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[Sumboodie]

Size your EMT based on the number and size of conductors in any particular run.

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Most would be 3 wires, 12 or 14 gauge.

 

[engineer2]

You'll be wanting 3/4 EMT for the bigger wires to feed a welder or air compressor.
If you have a home run with lots of circuits going a fair distance 3/4 is easier to pull and allows room for future upgrades.

Here's one to calculate mixed wire sizes.

Conduit Fill Calculator | Southwire

Get accurate conduit fill percentages with Southwire's Conduit Fill Calculator. Perfect for electricians, engineers, and contractors.

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[sparky 1971]

Bring 3/4" out of the panel in order to fit multiple circuits. Drop down to 1/2" at junction boxes to send circuits different directions. I try to run everything at the tops of the walls, the furthest circuits and lights getting to top conduit and the closest getting the bottom in order to keep from crossing conduits.

 

[torqueman2002]

Good information ^^.
I'm updating our mid 70's house and have found "Gardner Bender ERB-UG Ugly's Electrical Reference Book, Wiring Simplified" very consice and understandable.

My local laws allow plastic conduit, which I've used in the shops in the basement and attached garage.

 

[ycgoat]

Depending on Budget, and what kind of looks you like, you can use wiremold or panduit wireways since its all exposed vs conduit

 

[alfredeneuman]

you can use wiremold or panduit wireways

Metal wireways don't require derating for the number of conductors in a raceway until 30.
Plastic raceways begin at 3+ conductors.
Wiremold's available in either.....Panduit has just plastic.

 

[grounded-b]

Metal wireways don't require derating for the number of conductors in a raceway until 30.
Plastic raceways begin at 3+ conductors.
Wiremold's available in either.....Panduit has just plastic.

Wiremold and Panduit ( plastic and metallic), are both classified as "Raceways" NEC Art 386 and 388

A "wireway" NEC Art 376 and 378 have hinged or removable covers.

Surface Metal Raceways require derating.

NEC 310.15(B)(3)a (paraphrasing) When a raceway (over 24" in length), or cables (bundled tightly for more than 24"), contains more than 3 current-carrying conductors, the ampacity shall be reduced as shown in Table 310.15(B)(3)(a). 4-6 conductors get de-rated by 20%, 7-9 conductors get de-rated by 30%, 10-20 conductors get de-rated by 50%

No distinction between metallic and non-metallic raceways

 

[alfredeneuman]

Wiremold and Panduit ( plastic and metallic), are both classified as "Raceways" NEC Art 386 and 388

Metallic Raceways
386.22 Number of Conductors
The adjustment factors of 310.15(B)(3)(a) shall not apply to conductors installed in surface metal raceways where all of the following conditions are met:
(2) The current-carrying conductors do not exceed 30 in
number.

Non Metallic Raceways
388.22 Number of Conductors or Cables.
The number of conductors or cables installed in surface nonmetallic raceway shall not be greater than the number for which the raceway is designed. Cables shall be permitted to be installed where such use is not prohibited by the respective cable articles.

Non metallic doesn't have the exception

 

[grounded-b]

Metallic Raceways
386.22 Number of Conductors
The adjustment factors of 310.15(B)(3)(a) shall not apply to conductors installed in surface metal raceways where all of the following conditions are met:
(1) The cross-sectional area of the raceway exceeds 2500 mm2
(4 in.2).

Ok. this would be correct, if he was installing Wiremold 3000 series raceway ( 1.5" x 2.75" cross-section ) or larger. Not for your run of the mill Wiremold 500 or 700 series raceway

 

[alfredeneuman]

Read what he wants> 50A circuits.. won't fit in a 500 or 700 (maximum wire size #10)

 

[sparky 1971]

Who in the blue hell would want to use Wiremold in a shop? It's an absolute pain in the *** to use. If anything is going to be run exposed in the apartment, WM may be the way to go but there's no way I'd even give it a thought in the garage,

 

[Sumboodie]

Good information ^^.
I'm updating our mid 70's house and have found "Gardner Bender ERB-UG Ugly's Electrical Reference Book, Wiring Simplified" very consice and understandable.

My local laws allow plastic conduit, which I've used in the shops in the basement and attached garage.

I have that book somewhere. I set it aside during the move and yeah... it's in a box... one of them!

 

[ycgoat]

Who in the blue hell would want to use Wiremold in a shop? It's an absolute pain in the *** to use. If anything is going to be run exposed in the apartment, WM may be the way to go but there's no way I'd even give it a thought in the garage,

LOL, I mentioned Surface mounted raceways, because the OP said it was all finished and seemed to be concerned about looks. Some people don’t like the look of exposed conduit.

 

[Sumboodie]

LOL, I mentioned Surface mounted raceways, because the OP said it was all finished and seemed to be concerned about looks. Some people don’t like the look of exposed conduit.

Conduit is what I planned to use, just was wondering about the size.

 

[Sumboodie]

Conduit is what I planned to use, just was wondering about the size. It's a workshop and apartment, not the Taj Mahal with fine Eye-Taliun granite and rich Corinthian leathers.

I'll be happy just to have a fresh coat of paint over the grime and being rid of all the mouse turds.

 

[Terry D]

Who in the blue hell would want to use Wiremold in a shop? It's an absolute pain in the *** to use. If anything is going to be run exposed in the apartment, WM may be the way to go but there's no way I'd even give it a thought in the garage,

Im doing a school. Anything on exposed brick walls is spec out in wiremold. I agree that stuff is a PITA. Expensive and at least around here, little hard to get.

 

[NBN]

I'm wiring a 30x40 right now. I'm the helper and my electrician recommends what I get for him to install. He recommended 1/2" EMT for the runs I needed.
I found 3/4" on marketplace at a big discount and bought that instead. Once installed and wires were being pulled, my electrician said he was glad that I went up a size, Made his job a bit easier.

In short - go 3/4". you'll have room for what you are running and may have room to add later on, if needed.

 

[Sumboodie]

I'm wiring a 30x40 right now. I'm the helper and my electrician recommends what I get for him to install. He recommended 1/2" EMT for the runs I needed.
I found 3/4" on marketplace at a big discount and bought that instead. Once installed and wires were being pulled, my electrician said he was glad that I went up a size, Made his job a bit easier.

In short - go 3/4". you'll have room for what you are running and may have room to add later on, if needed.

I'm told 3/4 is harder to bend? Nearly all the runs will be single run I think. IE panel to switch to light, or panel to outlet

 

[sparky 1971]

3/4 is harder, but not that much harder. I'm reminded of what one of the old guys close to 30 years told me. "If I ever catch you bringing a 1/2 out of a panel on one of my jobs, I'll kick your ***". That's stuck with me and I still try to follow it to this day when doing new construction. Service calls, especially the residential add a single 20 amp circuit type are different and I will use 1/2 for those.

 

[NBN]

Harder, but not enough for concern

 

[kaffine]

I'm told 3/4 is harder to bend? Nearly all the runs will be single run I think. IE panel to switch to light, or panel to outlet

It is a bit harder but not much. 1 inch took a bit of effort. I would use 3/4" unless a run really needed 1 inch. I wouldn't use 1/2" unless there was a large cost difference. I would rather try and keep everything 3/4" so I don't need to have parts for another size.

 

[dscheidt]

It is a bit harder but not much. 1 inch took a bit of effort. I would use 3/4" unless a run really needed 1 inch. I wouldn't use 1/2" unless there was a large cost difference. I would rather try and keep everything 3/4" so I don't need to have parts for another size.

3/4 emt is about 50% more than 1/2. So are fittings. boxes are the same, more or less, but some styles are harder to find with 3/4 knockouts. So there's a real cost in material. It's also harder to work with, not only is harder to bend, it's got a larger bending radius, and it's harder to get into place in a wall. A 10' stick of 1/2 can be fed into the middle of stud wall, with just an oversized hole at the first stud, 3/4 can't unless you're Paul Bunyan. some of this doesn't matter in a shop, but in finished work it does.

 

[kaffine]

3/4 emt is about 50% more than 1/2. So are fittings. boxes are the same, more or less, but some styles are harder to find with 3/4 knockouts. So there's a real cost in material. It's also harder to work with, not only is harder to bend, it's got a larger bending radius, and it's harder to get into place in a wall. A 10' stick of 1/2 can be fed into the middle of stud wall, with just an oversized hole at the first stud, 3/4 can't unless you're Paul Bunyan. some of this doesn't matter in a shop, but in finished work it does.

Looks like buying 200 feet would be about $100 difference between 1/2" and 3/4" then I wouldn't need to buy a half inch bender saving a bit of that money assuming I have some runs that require 3/4". Granted other parts are going to cost a bit more in 3/4 vs 1/2. I can't remember ever regretting putting in larger conduit but have serval times wished I had used larger conduit.

My name is Paul but not Bunyan.

 

[Sumboodie]

I expect to need a fair bit more than 200 ft. 1/2" can fit 9 12 gauge wires or 12 14 gauge

 

[grounded-b]

I expect to need a fair bit more than 200 ft. 1/2" can fit 9 12 gauge wires or 12 14 gauge

1/2" will fit those number of wires, but you will have to de-rate the ampacity of the wire after 3 current carrying conductors. 80% capacity for 4-6 conductors, only 70% when you have 7-9 conductors in a raceway

 

[Sumboodie]

1/2" will fit those number of wires, but you will have to de-rate the ampacity of the wire after 3 current carrying conductors. 80% capacity for 4-6 conductors, only 70% when you have 7-9 conductors in a raceway

Ok, thanks, didn't know that. So makes sense to use 1/2" then, as I can only have 1 feed in a conduit in any case. I'll probably use 3/4 for the couple lines that need 6, 8 or 10 gauge for the 240v feeds.

 

[dscheidt]

1/2" will fit those number of wires, but you will have to de-rate the ampacity of the wire after 3 current carrying conductors. 80% capacity for 4-6 conductors, only 70% when you have 7-9 conductors in a raceway

this usually turns out to be a non-problem. 12 AWG THHN has a current carrying capacity, per the NEC, of 30A at 90 degrees celcius. Derate that to 70%, and you are at 21 A. It's only a problem if you're using something other than thhn, there's another reason to derate (ambient temperature, for instance).

 

[dscheidt]

Ok, thanks, didn't know that. Is neutral considered current carrying?

Depends. In a two wire 120V circuit, yes. in a three wire 240 V circuit, no. this is why multi-wire branch circuits (MWBC) are so common in conduit. You can put 9 12awgs thhn wires in 1/2 conduit. That's 4 (and a half...) 120 V circuits and 8 current carrying conductors. Use MWBCs and you get 6 120V circuits with six current carrying conductors.

 

[Sumboodie]

this usually turns out to be a non-problem. 12 AWG THHN has a current carrying capacity, per the NEC, of 30A at 90 degrees celcius. Derate that to 70%, and you are at 21 A. It's only a problem if you're using something other than thhn, there's another reason to derate (ambient temperature, for instance).

Was planning to use 12 guage for the 15 and 20 amp circuits. I may pickup spools of 14 for a few light load circuits, but it will depend on price if it's even worth it.

 

[Sumboodie]

Was planning to use 12 gauge for the 15 and 20 amp circuits. I may pickup spools of 14 for a few light load circuits, but it will depend on price if it's even worth it.

I think it's just as well to make the outlets all 20 amp.

 

[Sumboodie]

The panel is flush mounted. Can I just fire in an "LB" 6" above the panel, let's say a foot above, and pull the wire through the wall into the panel?

 

[Shiftless]

For the short runs around my garage and basement, I find it easier to use one size wire. 12
I only want one spool each of black, red, white, and green.

 

[Sumboodie]

It won't let me fix my grammar....

The panel is flush mounted. Can I just fire in an "LB" above the panel, let's say a foot above, and pull the wire through the wall into the panel?

 

[Sumboodie]

For the short runs around my garage and basement, I find it easier to use one size wire. 12
I only want one spool each of black, red, white, and green.

What I was thinking, unless 14 guage is way cheaper. I'll need to pickup some larger stuff as well for at least 1 welder outlet, and likely for the dryer in the apartment.

Currently the whole apartment is running off the dryer feed... somehow. And that is on a 20 amp breaker, and wired with I think UF burial cable.
Somehow this wasn't noticed on the home inspection. I found out when I had the clothes dryer running and fired up the vacuum.

 

[Shiftless]

It’s good that you are getting that hack job straightened out.

 

[dscheidt]

Was planning to use 12 gauge for the 15 and 20 amp circuits. I may pickup spools of 14 for a few light load circuits, but it will depend on price if it's even worth it.

I think it's just as well to make the outlets all 20 amp.

Around here, the current price of solid 12AWG thhn is about $100 for 500 ft; 14 AWG is $70.

The panel is flush mounted. Can I just fire in an "LB" 6" above the panel, let's say a foot above, and pull the wire through the wall into the panel?

No. THHN and related types can't be used outside of a raceway of some sort. you could convert to romex (in a box, not an LB) and pull that to the panel. Or you open the wall, and run conduit.

 

[Norcal]

Was planning to use 12 gauge for the 15 and 20 amp circuits. I may pickup spools of 14 for a few light load circuits, but it will depend on price if it's even worth it.

I think it's just as well to make the outlets all 20A

Why?? There is almost no reason so spend the extra money for 20A devices, since 15A duplex receptacles can be used with 20A circuits if you need 20A then a dedicated circuit is required. 29 years ago I used 20A duplex receptacles in my shop because I had them, not once has one been needed.

 

[Sumboodie]

Around here, the current price of solid 12AWG thhn is about $100 for 500 ft; 14 AWG is $70.

No. THHN and related types can't be used outside of a raceway of some sort. you could convert to romex (in a box, not an LB) and pull that to the panel. Or you open the wall, and run conduit.

The stuff I already have came from an old job wiring a shop (was leftovers the electrickcans left behind) and it's stranded wire. That better or worse?
I have I think 2 500ft spools of red and black in 12 guage and a spool of green, but I can't remember for sure.