Electric for woodshop

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  #1  
Old 08-28-15, 12:05 AM
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Electric for woodshop

Hi,

I just purchased a 10x20 lofted barn for my woodshop. I plan on using the following tools:

Table saw (13A)
Miter Saw (13A)
Air Compressor (15A)
Air Conditioner (15A)
Router (12A)
Lights (15A)

The amperage of each component is listed beside the tool. Although an Air Conditioner is not a tool, I plan on getting a small window unit to use during the summer for cooling off. I do not plan on using all of these tools at the same time. I do plan on adding tools down the road. I thought about installing a 100A breaker box inside the building with a feed from the house, approx. 50ft -100ft.

I know I will have to bury the cable in conduit. I also plan on running the cable inside the building in metal conduit for the receptacles and lights. I also know that I will have to use 2AWG wire.

I have been reading that I may have to buy GFI breakers, due to moisture.

I will probably have to separate the ground bar from the neutral bar inside the panel.

My questions:

Will a 100A box be sufficient for what I want to do?

Being the cost of the wire per foot, would it be beneficial to have the electric company come out and add a pole and meter for the building?

Will I need to drive a separate grounding rod for the building?

More questions to come as I think about them.

Thanks,
Chris
 
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Old 08-28-15, 01:08 AM
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I know I will have to bury the cable in conduit.
If you use conduit it is best not to use cable. If you use cable just direct bury it sleeving it with short sections of conduit where it needs protection. If you use conduit best to use individual conductor. You may want to consider aluminum MHF (Mobil Home Feeder) such as 2-2-4-6 on a 90 amp breaker to keep costs down.
I have been reading that I may have to buy GFI breakers, due to moisture.
Lights and 240v receptacles do not need GFCI protection. For 120v receptacles you can use a GFCI receptacle as the first receptacle on each circuit and use non GFCI from the load side of the GFCI for the rest of the receptacles on the circuit.
Will a 100A box be sufficient for what I want to do?
Yes.
Being the cost of the wire per foot, would it be beneficial to have the electric company come out and add a pole and meter for the building?
Even if they were willing to probably not with the monthly sur charges that are usually tacked on to the bills.
Will I need to drive a separate grounding rod for the building?
Yes, either one or two depending on local regulations.

Would suggest a 12 space or larger main breaker kit for the subpanel. They are usually the cheapest way to go because they include an assortment of branch circuit breakers and the main breaker which will serve as your code required disconnect. You will also need to buy a ground bar to add to it.
 

Last edited by ray2047; 03-06-17 at 05:50 AM.
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Old 08-28-15, 02:23 AM
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Instead of buying a 100A breaker box with 20 slots, could I buy a smaller box, like you were suggesting and use a 60A breaker for the main?

At most, I would be continuously running the window AC unit and lights, along with whatever power tool I will be using at the time. Generally, I would not be using 2 or 3 tools at the same time.

With that being said, could I get away with a 60A breaker, smaller box, and using the MHF wire?

My apologies - When I said cable, I was thinking about the THHN wire that lowes sells for 1.79 per foot and running that in the conduit.

Would the MHF wire be better? Could it be direct buried or does it need to be run in conduit?
 
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Old 08-28-15, 05:01 AM
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I have a 60 amp service for my shop/barn and use a lot more tools [welder too] than you mentioned. It's never kicked the main breaker but I almost always work by myself. I'm sure it wouldn't be enough if I had a crew out there using multiple tools at the same time.

Mine has the mobile home type feeder wire. Mine is in conduit all the way because the ground is too hard to dig deep enough but the wire can be direct buried [3' I think] but it must be in conduit where it enters/leaves the ground.

If Ray says anything different - listen to him! he's the electrician, I'm just a painter
 
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Old 08-28-15, 05:52 AM
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Thanks for the reply, Mark. I may have ran across your post and was reading them while waiting on replies.

I don't think I will like driving the grounding rod into the ground though. My yard is mostly rocks. I'm sure it will eventually turn into red clay after I drive my rod through some rocks.

Any easy way to drive a ground rod? I have heard some people use water, others use a jackhammer, others use sledge hammer.
 
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Old 08-28-15, 06:04 AM
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To me, driving in the ground bar is the easy part. A shovel or digging bar can be helpful at the start but after that I've used a sledgehammer.
 
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Old 08-28-15, 09:01 AM
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The ground rod can be driven at 45 if needed or a trench dug and buried in the trench. There is also a Ufer ground where the wire is connected to the rebar of your slab. A " or " hammer drill can also be used to drive the ground rod. They make a special drill attachment or try just chucking the rod in the drill.

Direct burial of cable is 24". You only need 18" for conduit.
 
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Old 08-28-15, 09:47 AM
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Sounds like I may have to rent a trencher and a hammer drill.
 
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Old 08-28-15, 09:50 AM
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What about the breaker box? Could I run 60A service instead of 100A? I saw a 125A breaker box with 12 slots that I thought about grabbing and using either THNN in conduit or MHF 4-4-4-6 feeder cable.
 
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Old 08-28-15, 11:01 AM
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What about the breaker box? Could I run 60A service instead of 100A?
Yes.
I saw a 125A breaker box with 12 slots that I thought about grabbing and using either THNN in conduit or MHF 4-4-4-6 feeder cable.
Yes that would be a good choice. Since the main breaker in the sub is only used as a disconnect switch the 125a main breaker is okay to use.
I thought about grabbing and using either THNN in conduit
You would need to use THWN but most wire is dual rated THHN/THWN and Bigbox incorrectly calls it THHN.
or MHF 4-4-4-6 feeder cable.
Compare the price of aluminum MHF to three copper #6 THWN and one copper #10 THWN. You might also look at aluminum #4 XHHW.
 
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Old 08-29-15, 06:33 AM
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I am going to attempt to add a couple of pics of my breaker box and service disconnect panel. I am having a bit of a road block when trying to figure out how to wire my building into the breaker box. The breaker box has enough space, however, I don't have any way to get the wire from my breaker box to the outside of the house. The only way I can think of is to run it down the main wire conduit for the whole house.

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The other option is to run a breaker from the service disconnect panel on the side of our manufactured home. In our case, this is not a mobile home. It does not have wheels on it and is grounded to earth ground via grounding rod.

Here is a pic of the service disconnect.

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The service disconnect has a ground, 2 hots, and neutral that runs into the breaker box. I'm thinking this belongs to the electric company and am unable to add a breaker, although, I can access it.
 
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Old 08-29-15, 08:50 AM
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The service discponnect is loadcenter with feed-through lugs. You can put your breaker to feed the shop in this loadcenter.
 
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Old 08-30-15, 02:44 AM
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So I can buy a breaker and put it in, provided that I turn off the disconnect breaker so I don't get shocked?

What about connecting the ground and neutral wire? I won't get shocked while hooking those up?

I'm guessing as long as I stay away from the two hot wires into the disconnect breaker, I should be fine.

Does that panel belong to the electric company? I thought it was their equipment.
 

Last edited by cdawley4; 08-30-15 at 02:47 AM. Reason: Spelling errors
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Old 08-30-15, 06:54 AM
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Are the wires coming in from the meter going into the lugs near the bottom of that panel?
 
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Old 08-30-15, 11:11 AM
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No, the wites at the bottom go into the conduit, under the house, and into the breaker box inside the house. The two hot wires are on top of the service disconnect breaker.

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Hope this helps.
 

Last edited by ray2047; 08-30-15 at 12:29 PM. Reason: Rotate, crop, and enlarge image.
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Old 08-30-15, 07:45 PM
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So I can buy a breaker and put it in
Yes, or you could hire someone to do it if you don't feel comfortable doing it. Safety first, shut the main breaker off and the two bus bars under the main breaker will be dead. Always test the bus bars before assuming the power is off.

What about connecting the ground and neutral wire? I won't get shocked while hooking those up?
The neutral and ground wires are terminated on the neutral bus to the left of the power bus where the large ground wire is already terminated. You shouldn't get shocked if the main breaker is off. If you don't feel comfortable doing this, call a professional.

Does that panel belong to the electric company? I thought it was their equipment.
No, you own it and have to maintain it and one day may have to replace it. The metering section (the top) is sealed to keep you out.

Last edited by ray2047; Today at 01:29 PM. Reason: Rotate, crop, and enlarge image.
Thanks, Ray, that helped a lot.
 
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Old 01-02-16, 01:22 AM
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Sorry for digging up an old post. I thought I was done with this, but had a few more questions and didn't want to start a new topic.

I am now getting around to running the electricity to my building. In regards to the wire, I was thinking of buying 200' of #6 wire and running 2 wires to the building underground instead of running 3 or 4 wires.

My thinking is that I will have the ground wire coming off the grounding rod at my building and that would supply the necessary ground for my building.

Would I need to run a ground wire from the service disconnect panel to the building as well?

How many wires do I physically need inside the conduit and where would they connect from/to?

I am probably confusing myself as well.

Thanks,
Chris
 
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Old 01-02-16, 02:01 AM
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I just answered my own question with the sub panel diagrams in the sticky section.

Duh!
 
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Old 01-02-16, 06:07 AM
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Please run the required 4 wire feeder to the workshop.
 
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Old 01-02-16, 07:17 AM
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When you figure out the electrical load, you should assume that the air compressor, the air conditioner or heater, a refrigerator for refreshments,and an exhaust fan for sawdust, paint vapors, etc. will all be running at the same time together with tools you will be using. You can assume that an air conditioner and a heater will not be running at the same time. If more than one person will be working you need to allow for more tools to be running at the same time.
 
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Old 03-06-17, 01:48 AM
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Hi,

Finally getting around to buying wire for my shop. Although, it is going on 2 years, I have been involved in various projects around the house and had to put the shop on hold.

With that being said, I found some MHF wire from wire and cable your way. It appears they have great prices when compared to big box stores.

I was thinking about getting either

https://www.wireandcableyourway.com/...der-cable.html

or

https://www.wireandcableyourway.com/...der-cable.html

With that being said, if I wanted to step up to a 100A breaker later, would that wire allow it?

I'd rather have the right wire the first time than to run new wire and do it all over again to step up from 60A breaker to 100A breaker.

Would this need to be buried in conduit? From what I read, it says it is direct burial, but does direct burial mean bury in conduit or dig trench and lay it in?
 
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Old 03-06-17, 06:33 AM
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The #2 aluminum can be over current protected up to 90 amps, so no on the 100A feeding breaker. Also don't use the 2-2-4-6 because it has a reduced neutral and you will need to calculate your unbalanced loads to determine if a reduced neutral can be used. The 2-2-2-4 is your best option. Do you want to use conduit? If so then there are other options of wire to use. The MHF even though being direct bury needs to be in conduit where above ground and inside the structure.
 
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Old 03-06-17, 10:04 AM
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I can get by with 60-90 amps. Was interested in getting wire that would support 100A if needed. I don't think I will need 00A right now,as I don't have much stuff. I can either use conduit or not if direct buried.
 
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Old 03-06-17, 11:39 AM
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IMO if you are going to use 100 amp wire, I'd install a 100 amp breaker. Doesn't make a lot of sense to use the bigger wire and then change out the breaker later.
 
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Old 03-06-17, 12:03 PM
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For 100A you need #1 Al or #3 Cu. I suggest 2" PVC conduit using aluminum XHHW-2 wire in sizes of #1 for the three conductors and #6 for the EGC.
https://www.wireandcableyourway.com/XHHW-2/ XHHW-2 is not direct bury, needs to be in conduit the whole run.
 
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