Bringing 220V in the garage/shop

It's possible Vaughn's suggestion is the best yet: that you do it yourself, with your own hands, but with a set of experienced eyes watching over your shoulder. That way you learn (and I do think everyone should know how to do this stuff: no-one should feel powerless or mystified), you raise your comfort level and gain expertize, but you also have someone offering advice and guidance along the way (and perhaps preventing a difficult outcome).

It really is fairly simple, but it's also simple to make a mistake. I can remember one time making a home depot run, and being seriously worried the house would burn down before I got back!

If I'd had someone knowledgeable watching over my shoulder, I would have saved myself both time and anxiety!

Thanks,

Bill

Bill Lantry said:

It's possible Vaughn's suggestion is the best yet: that you do it yourself, with your own hands, but with a set of experienced eyes watching over your shoulder. That way you learn (and I do think everyone should know how to do this stuff: no-one should feel powerless or mystified), you raise your comfort level and gain expertize, but you also have someone offering advice and guidance along the way (and perhaps preventing a difficult outcome).

It really is fairly simple, but it's also simple to make a mistake. I can remember one time making a home depot run, and being seriously worried the house would burn down before I got back!

If I'd had someone knowledgeable watching over my shoulder, I would have saved myself both time and anxiety!

Thanks,

Bill

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When I wired my shop, I did just this... I ran all the wiring myself.. after questions to more experienced persons... I put in all the plugs and switches, using both info gleaned from my questions and a couple of hot-to books. I only paid the electrician to wire in the breaker box, connect the line from the house (main breaker on the pole outside the house) and to check my work... he only found one plug that was mis-wired... he was kind and suggested that I was getting tired when I got to that one... he also drove the 6' grounding rod into the ground...

Mohammad Madha said:

Thanks Chuck and Bill. Your cost figures give me an idea of how much it would cost. I guess I posed the wrong question when I asked how much it would cost me. I should have asked, what did you do in your situation and how much did you pay for it. I am not looking for an exact figure but a rough idea like, under $500, under $1000, etc.

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Well I spent better than 4K on my wiring job.
Of course my entrance panel is a 400 amp. Than the 3 subs off from it. And the 900 feet of 00 wire. The list just keeps going on and on.

Thanks Chuck. I hope I won't have to spend that much.

I bet yours wont look like this

Chuck Thoits said:

I bet yours wont look like this

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If it does, the DEA may be paying a visit looking for sunlamps underground.

Bill Lantry said:

Every single outlet in my shop is GFCI.

And every one in the kitchen. And the bathrooms. And all of them have those little lights on them, so I know it they're working or tripped. ...

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Bill,

I'm still trying to understand the reason for a GFCI outlet at every position. The normal installation is to have a GFCI at the first position with all others fed through it.

I bring this up again for those who aren't well-versed in electrical circuits. GFCI outlets are several times the cost of a standard outlet. In my area, purchasing contractor packs makes the unit cost of standard duplex outlets $1 or less. A multi-pak of GFCI's makes them about $7 each. Cost aside, there is no technical reason to have GFCI at each position; they have a line side that is attached to the electrical feed and a load side that feeds all other outlets in the string.

Bill Arnold said:

Bill,

I'm still trying to understand the reason for a GFCI outlet at every position. The normal installation is to have a GFCI at the first position with all others fed through it.

I bring this up again for those who aren't well-versed in electrical circuits. GFCI outlets are several times the cost of a standard outlet. In my area, purchasing contractor packs makes the unit cost of standard duplex outlets $1 or less. A multi-pak of GFCI's makes them about $7 each. Cost aside, there is no technical reason to have GFCI at each position; they have a line side that is attached to the electrical feed and a load side that feeds all other outlets in the string.

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I agree Bill, I have 2 GFI in my shop both feed 2 circuits, the rest of the receps. I installed and no GFCI's

I asked an electrician to give me an idea on the cost. He said that my main panel has 100 Amp service and the underground conduit that runs from the main panel to the garage is half an inch in diameter. He said that he can pull an extra cable thru the conduit but it will only allow a 30 Amp sub-panel with two 220 v breakers. I am not sure if that will be enough to run two machines at the same time. It may be cutting it too close.

Second option is to run a new underground 1.5" diameter conduit. He would install a 70 Amp sub-panel with 50 Amp capacity.

First option is about $300. Second is about $1200. Does this sound reasonable?

Cost sounds reasonable. Don't remember what you have in your back yard to dig around/under to get the conduit run.

You need to look at the amperage/wattage of your machines and figure out what they draw (amps wise). Sounds like it would be close for say a planer and dust collector, but couldn't tell you for sure without knowing what you have.

If it's affordable, my suggestion would be to go with the bigger option. I don't think the price is out of line, assuming it includes the permit fees and such.

You might check with your electrician to see how much the 1 1/2" conduit run would cost if you do most (or all) of the trenching. When I had power run to the garage at my last house, the electrician was willing to knock off several hundred dollars if I dug the trench. (Mine was a longer run than yours, though.) By sheer luck, the next weekend my 20-something nephew came to visit for a few days, and he dug the trench in exchange for food and lodging.

I just found this thread so my comments my repeat what others have said.

Here in CA, the owner can pull an electrical permit for their own home. You can hire someone to work with you on an hourly basis but not on a fixed fee basis (this is an attempt to keep unlicensed "electricians" from getting a job, but it is only partly effective).

Installing a sub-panel is not very difficult. You might pull the permit yourself, then find an electrician who will help you and give you advice (for a price) about meeting the code. I've found that electricians will work with you unless you're obviously incompetent.

Regarding the feeder wire, I'd certainly put new wire in, and I'd go bigger than what you need so that if you want to increase the capacity in the future you don't have to pull new wire. Go with copper wire - don't let anyone talk you into aluminum wire. 60 amps for the subpanel is probably enough for most home woodworking shops.

Regarding a main breaker in the sub panel. Some panels don't come with a main breaker and adding one can be expensive. An alternative is to use one of the two gang breakers and feed your input into the breaker. The breaker connects to the bus bars in the panel, which is exactly what the main breaker does. The disadvantage is that you lose one double breaker position in the subpanel. Make sure you clearly label that breaker as "Main" so other people know it's the main shut off. I think it's required by code to have that label.

Almost all brands of 120V breakers can be purchased as double breakers - that means that you get two 20 amp (for example) breakers in the space of one standard 20 amp breaker. The double breakers are more expensive but can give you a lot more circuits in the box.

If you don't want to install the sub panel yourself, get an electrician to do it but pull all the other wiring yourself (and make sure you use 12 gauge wire, not 14 gauge). Pulling wire is mostly a grunt job and you'll be paying electrician prices for grunt work.

After you pull all your wire, get those metal plates that you nail to the 2x4 and put them everywhere the wire goes through a 2x4. They're not required if the wire is exactly in the center of the 2x4 but we (woodworkers) attach a lot of stuff to the walls with big, long screws and you don't want to put a screw into a wire. It's good and cheap insurance.

If you're pulling in a finished garage, don't be afraid to remove strips of drywall so that you can pull the wire. It's easier to patch if you remove a long strip than if you make a lot of holes. Try to keep the strip even so that it's easier to cut the piece of drywall that you'll put back in. Doing drywall is easy but dirty work.

Finally, make sure all the 120V outlets are GFCI protected. GFCI can save your life - the cost is cheap insurance and is required by code anyhow.

If you have questions about anything I said, I may have pictures from when I did my electrical work and can show you what I mean by some of my statements.

Good luck!

Mike

[I know a good electrician here in Orange county. Don't know if he'll do work in LA, however, but if he has an empty day he may be willing to (maybe offer something for the travel). If interested, PM me.]

I'd go with the bigger option depending on tools. 30A 220V is probably fine for a shop that is using all 110V tools. You could use a 3hp tool, but you're going to be limited on the DC HP and other stuff running at the same time.

50A should get you a couple 3hp items and accessories fine.


Power draws vary, but max draws I came up with when figuring my shop out:

220V items
5hp - 25A
3hp - 15A
2hp - 10A
Window AC 220V - 15A
Mini high effieciency Heat Pump - 220V 8A

110V items
1.5hp - 15A
Lighting - .5A per double 4' flourescent
Battery Chargers - 1-2A each
Computers - 5-10A
Fan - 5-15A
Plug in Tools - up to 15A
Air Compressor - 15A

Those prices don't seem to bad to me either.

Thanks for all the suggestions.

Good idea Vaughn. I will ask the electrician.

Darren and Jeb, the machines in my shop have these motor ratings:

CMS 15A
DC 12A
DP 11A
Lathe 6.2A
Air Filter 3.9A

I do have plans to acquire more machines like table saw, jointer, bandsaw, compressor and a planer. I think 30 Amp sub-panel may be a borderline solution that I may not be happy with in the long run.

Mike, thanks for your input and the info about the permits. I didn't understand your explanation of double breakers. The problem was not your explanation but the lack of my basic electrical knowledge. Also, not sure what type of metal plates you were referring to.

Mohammad Madha said:

Mike, thanks for your input and the info about the permits. I didn't understand your explanation of double breakers. The problem was not your explanation but the lack of my basic electrical knowledge. Also, not sure what type of metal plates you were referring to.

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Let me address the plates first. I'll take a picture and post it about the breaker, later.

Look at the pictures attached. You'll see the wire running through the 2x4s and where the wire runs through, there's a shiny plate. Look at the closeup picture and you'll get a better view. These are plates sold in the electrical section of a borg, and they're designed specifically for this purpose. If the wire is not exactly in the center of the 2x4 you are required by code to put one of these plates over the wire to keep someone from putting a screw or nail into the wire.

Since we use long and big screws to attach stuff to our walls, it's good to put these plates over every 2x4 where the wire goes through.

Mike

Okay, let me see if I can explain the breaker situation.

Here's a low cost subpanel, shown with the door closed.


And here it is with the door open. Note the knockout panel at the top of the panel, which has not been knocked out. This is where your main breaker would normally go.
Also, note the top left breaker, which has a blue label next to it. The label says "main" which indicates it's the main breaker. There's also a blue label on the top left breaker (which I put on upside down) that says "service disconnect".


Here's a closer look.


Now let's look inside. Normally, if you were not using a main breaker, the two hot service lines would connect to the main buss bars, one of which I'm pointing to with a pencil.


Instead of attaching there, and not having a main breaker, or buying a special and expensive main breaker which would be installed at the top of the buss bars, I used one of the standard double breakers, as you can see in this picture.


This is acceptable by code. The advantage is that a standard double breaker (here a 50 amp breaker) is less expensive than a breaker designed to fit at the top of the buss bars. The disadvantage is that you lose one double breaker space.

Because I lost that space, I had to use a 120V double breaker. Look down the breakers on the left side. The second breaker up is a double 120V breaker (two 120V breakers in the space of one standard breaker). The double 120V breakers are a bit more expensive but give you an additional circuit when the panel is full.

I hope I explained that so it's understandable.

Mike