Workshop wiring

[Brogan]

Have the builder put in a 60amp sub panel and then do the rest later in exposed conduit. That way you can calmly plan what you need/want. With a little guidance, wiring isn't a big deal. Homeowners can typically pull their own permits and do their own wiring.

A 100 amp sub panel might be better just from the standpoint it will hold more breakers. Cost will depend a lot on how far the sub is from the main disconnect panel.

What you don't want to do is have all your shop lighting fed from the sub panel. If the main breaker to/in the sub ever trips your lights will also go out if fed from the sub.

As long as the builder doesn't quote something crazy for the 100A sub panel, this is the way I'm going to go.

The image below shows where the main panel is (about 6 feet to the left of the arrow) in relation to the new panel, with the proposed 110V 20A and 220V 20A and 30A outlets.

I'll run some PVC conduit (http://www.homedepot.com/p/1-in-x-10-ft-PVC-Schedule-40-Conduit-67462/202295893) from the top of the 100A sub panel over the windows and down to the outlets.
From what I've read, it is permissible to run 110 and 220 branch circuits in the same conduit, as long as the total number of wires doesn't exceed the limits in this table: http://www.constructionmonkey.com/calculations/electrical/tables/wireconduit

I could use EMT but it's a lot harder to work with and I don't need the additional protection.

The lighting, etc. are all on different circuits so no worries there.

Thanks again to everyone for the input.

 

[DaveD]

There is nothing stopping you from plugging 2 or more 240 volt pieces of equipment into one breaker/receptacle.
Just make up a short extension cord with multiple receptacles on one end and a plug on the other end. I built a welding cart that has 3 50a, 240v receptacles on it , with a 2' pigtail cord that plugs into a extension cord that then plugs into one 50a wall receptacle.

One thing I absolutely hate doing is plugging/unplugging equipment/cords throughout the day. I also have multiple 20amp, 240 receptacles and 4 quad 120v outlets. Even some of my extension cords have quad boxes on them.

 

[zapdafish]

not sure why subpanel needs to be so far away from main panel. Do you have your tools already? I have 3 220v tools and each has a different prong configuration.

I'm jealous of your windows

 

[DaveD]

A lot of your expense is going to be the wire from your main panel to that sub panel. Move the sub panel all the way to the left and shorten the run. In my last shop I had the panel close to the entrance door so I could easily get to it.
I also used mine as a total disconnect for the shop.

If I had a sub panel in my garage where yours is pictured I probably couldn't find it today. You would be hard pressed to see the walls in my garage/shop.

BTW, yes you can put multiple circuits in one conduit.

One last thing. The sub panel, without breakers is pretty cheap. It's the breakers that cost the money. Go to Lowe's or HD to get an idea on prices. Your contractor will probably charge you double the cost you see.

Realze that contractors probably charge $70-100 per hour and hate small jobs with a passion. Doesn't matter that they are probably paying the worker $20/hour. That's why I do my own plumbing, electrical, maintenance and carpentry. Over the years I have saved thousands of dollars that I was then able to put into tools for my hobbies.

 

[Brogan]

I figured the sub panel would be better off placed close to the outlets, which are all going to be on that wall and where the equipment will be located.

Otherwise it means running conduit all along the rear wall and then down to the outlets, and much longer runs for the branch circuits.

If the builder does put the sub panel in I'm going to do the work myself, so the only expense will be materials (and the permit).

 

[Brogan]

This is the same garage as mine but the opposite layout.

It gives a better idea of the overall finish and where the main panel fits.

 

[LB75]

A lot of your expense is going to be the wire from your main panel to that sub panel. Move the sub panel all the way to the left and shorten the run. In my last shop I had the panel close to the entrance door so I could easily get to it.
I also used mine as a total disconnect for the shop.

Exactly what Dave said. The distance from your main to that sub panel location you have marked is really going to drive up the cost due to the high price of the cable. Get the sub panel as close to the main as possible.

The 12/2 Romex you'll need to run from your sub panel to the outlets is far cheaper than the feeder wire needed to connect the sub panel to the main panel.

 

[Brogan]

If I do that then I don't really need the sub panel - there is more than enough spare capacity on the main panel.

The only semi tricky part would be transitioning from a recessed panel to surface mounted conduit.

 

[DaveD]

Keep in mind that you can't run 'romex' in conduit. The only exception is if you are stubbing down from the ceiling for an exposed outlet. Then you can put that last 6 or so feet of the Romex in conduit to protect it.

One way, of several ways, to transition into the recessed panel is with flexible conduit. Also keep in mind that you will probably be able to only come into the top/bottom of the recessed panel because there will be a 2x4 on each side of the panel.

I'd still opt for the surface mounted sub panel. It will make adding your circuits a lot easier and you won't have to mess with a panel that already has a crap load of wiring in it. You also won't have to patch drywall every time you want to add a circuit.

 

[Brogan]

Keep in mind that you can't run 'romex' in conduit.

Yes, I was planning to run single strand wire as per code.

One way, of several ways, to transition into the recessed panel is with flexible conduit. Also keep in mind that you will probably be able to only come into the top/bottom of the recessed panel because there will be a 2x4 on each side of the panel.

That's exactly how it is - set between two studs - I was planning to come out of the top but I imagine I would still have to cut drywall (which is what I'm trying to avoid) in order to comply with code.

I'd still opt for the surface mounted sub panel. It will make adding your circuits a lot easier and you won't have to mess with a panel that already has a crap load of wiring in it. You also won't have to patch drywall every time you want to add a circuit.

I think you're probably right.

 

[Jeremy Scuteri]

Keep in mind that you can't run 'romex' in conduit. The only exception is if you are stubbing down from the ceiling for an exposed outlet. Then you can put that last 6 or so feet of the Romex in conduit to protect it.

I'm really curious about this. Do you know where this is outlined in the National Electric Code? I first heard from my father that you are not allowed to run Romex in conduit. Being the skeptical SOB that I am, I didn't take his word for it and tried to look into it. Tons of people online saying contradicting things as usual. I couldn't find anything in the NEC myself, but I am certainly no expert.

The last thing I did was ask a Greensboro Electrical Inspector about it. He said that there was no problem with running Romex inside conduit as long as I left it in it's jacket because the wires inside the Romex jacket aren't sufficiently labeled, so he wouldn't be able to identify them. (Many internet threads said you needed to take the wires out of the jacket to prevent excessive heat, just the opposite of what the inspector said...go figure) I wouldn't be surprised if I got a different answer talking to a different inspector.

Sometimes it is hard to tell which way is up. I'd love to check out some specific code references on the topic if you have them.

 

[Lowlander]

Its not in the code book. You just can't run it in wet and damp locations.

 

[Brogan]

Sometimes it is hard to tell which way is up. I'd love to check out some specific code references on the topic if you have them.

Indeed.
Trying to interpret the NEC and getting a straight answer is just slightly easier than learning quantum string theory.

You just can't run it in wet and damp locations.

Why not?

I do find it ludicrous that 120V outlets in a garage must be GFCI due to it being a 'damp' location, yet 240V circuits do not.

Based on a lot of stuff I've read doing my research, a lot of professionals think the whole thing is a money making business just for the sake of it.

 

[Lowlander]

300.9 Raceways in Wet Locations Above Grade. Where
raceways are installed in wet locations abovegrade, the interior
of these raceways shall be considered to be a wet
location. Insulated conductors and cables installed in raceways
in wet locations abovegrade shall comply with
310.8(C)

 

[Lowlander]

I'm saying that you can run romex in conduit. Circuits on GFI are installed in garage because they are usually tied to the outside boxes. Also may have to do with water heaters in the same space.

 

[LB75]

I do find it ludicrous that 120V outlets in a garage must be GFCI due to it being a 'damp' location, yet 240V circuits do not.

When I had my workshop inspected, the inspector explained that the GFCI requirement in a garage wasn't necessarily because it can be a damp location, it was because of the tendency people had to run extension cords outside from the garage outlets where they can get get rained on. Probably not too many cases of needing to run a 240V tool outside on an extension cord.

 

[Jeremy Scuteri]

I do find it ludicrous that 120V outlets in a garage must be GFCI due to it being a 'damp' location, yet 240V circuits do not.

I agree, a complete breakdown of logic from my perspective. When I put outlets in my unfinished basement shop several months ago, the 120v outlets had to be GFCI protected but the 240v outlets did not (240v GFCI receptacles aren't readily available either, I only know of a "Spa Panel" for hot tubs). Same story for "Tamper Resistant" receptacles (I had to replace a bunch of 120v receptacles that I put in that were not tamper resistant), that rule only applies to the 120v outlets, not the 240v ones.

 

[Jeremy Scuteri]

When I had my workshop inspected, the inspector explained that the GFCI requirement in a garage wasn't necessarily because it can be a damp location, it was because of the tendency people had to run extension cords outside from the garage outlets where they can get get rained on. Probably not too many cases of needing to run a 240V tool outside on an extension cord.

Huh, that actually seems reasonable to me.

 

[LB75]

Huh, that actually seems reasonable to me.

Yep, and that reasoning saved me from having to install GFCI outlets inside my shop. I had 2 GFCI outlets on the outside of the building that satisfied the requirement.

 

[Brogan]

That explanation just doesn't wash with me - it seems like a rule which was invented because of something which happened one time, perhaps.

People could do the same with standard outlets inside the house, running the cable out of a window or door.

Not to mention most (all?) new builds these days have dedicated external GFCI outlets.

The whole code/permit issue is crazy here.
I have to apply for a permit to install light fixtures and fans in existing ceiling junction boxes.
Yet I can knock up a home made extension cord or splitter, or rewire a plug on a device without a permit.

Rant over