220 & 110 wiring for the new shop

[DLausche]

Here's a question for you electricians out there...



I am in the process of building a new garage stall which will mostly be a shop for me and all my tools, etc. Anyways, our electrical panel is in the basement, in the corner of a finished family room. Virtually impossible to run new lines from there. But, I have an idea. House was originally wired for electric clothes dryer which is 220 - 2x30 amp breakers (8/4 wiring). We have a gas dryer now and this circuit is basically abandoned. Running line from the laundry room to the new shop is doable. I'm thinking I can remove the 220 outlet, reroute end of exising 220 wire to nearby location in laundry room and put in a subpanel in a location that is accessible, etc. From there, I think I can run a new line of 8/4 from that subpanel out to the new shop area. In the new shop, I would like to have 220 available in case I ever buy a 220 wire feed in the future (current one is 110). OK, the question I have - and I think the answer is NO is: Once I have a 220, 2x30 amp line out to the shop, can I put that into a subpanel and run 2 110 circuits off of it *and* have one 220 outlet as well? I'm thinking not but it would make getting the power out there a lot easier. I also plan on tapping into a 20A 110 circuit in the existing garage and using this in the shop area as well. That circuit only has 5 outlets on it so far so should be able to run a few more off of it.



Thanks for your feedback guys.



-Deon

 

[JimScott]

You can basically do what you are proposing, but you will only have a 30 amp 240 volt service for your shop. You can install a sub-panel from which you can run some 120 volt circuits from, but you are going to run out of capacity real quick. You also didn't mention distance, but if its very far you need to be concerned about voltage drop.

I don't know about your wire feed, but my arc welder requires 50 amps at 240 volts, so for it your setup would not work. I run my shop from a 100 amp breaker in my main (house) panel and have a combination of 240 v and 120 v circuits in the shop including a 50 amp (240 v) for the welder and a 30 amp (240 v) for my air compressor.

Good luck,

Jim

 

[DLausche]

Good points Jim. I forgot to mention distance. Probably about 30ft max from basement laundry room to new shop area. I think the 30 amp 220/240 would be enough for my needs because I am thinking about what most of you guys would call a pretty small 220v welder - something that takes around 25 amps. I'm thinking this would do better than my current Hobart 135 - enough to do what I will need in the future.



So, do you concur that I can run 1 220 outlet *and* a couple of 110 circuits off of this one 8/4 run. I know I would have to watch the total draw. In reality I have need for a welder very, very infrequently. Just trying to plan as best as possible for for future potential uses.



Thanks

-Deon

 

[JApol]

My dad didn't run heavy enough wire out to his shop. Now everytime the five finger discount 220v air compressor comes on it kills EVERYTHING including the radio.

 

[DLausche]

I should also maybe ask where I can find out the max rating of my current 8/4 wiring. It is aluminum wiring to this one circuit only. House was built in 97 so fairly new. What is the max rating on 8 gauge AL wire? I have some reference material to work from, but I fear this might be outdated info.



-d

 

[TowPro]

you also want to run 4 wire from your main panel to the sub panel, then remove the bonding screw in the sub panel. That was a ground problem will pass all the way back to your main panel. My sub panels do not have a main breaker.

 

[AKAMAC]

8 gauge aluminum is rated at 30 amps. If it was my shop, I would run a 6/4 copper Romex out to your shop. That would allow you a 50 amp sub panel. The access to your main dist. panel may look daunting but drywall is easy to replace.

What is your main service rated at? Do you have a 200 amp panel? Mike

 

[DLausche]

8 gauge aluminum is rated at 30 amps. If it was my shop, I would run a 6/4 copper Romex out to your shop. That would allow you a 50 amp sub panel. The access to your main dist. panel may look daunting but drywall is easy to replace.

What is your main service rated at? Do you have a 200 amp panel? Mike

Well, one of the mistakes when I built the house was only getting a 100 amp service panel. That panel is full with circuit breakers now but since I went overboard with the # of circuits and we have a small family & I am not a major welder, etc, I think overall 100A is not terribly bad. I would ask for 200A if I had been older and wiser at the time. I am willing to redo drywall from the main panel, but I dunow if my better half would approve of ripping out and relacing the entire basement ceiling. I might have to sleep in my new shop for quite a while if I did that . I would if it were me alone but I think somehow I must make work the existing 8/4 AL wiring, extended, with a subpanel of some sort.



I think I am limited to a 220, 30 amp circuit max in my new shop if I supply it the (workable) way I am thinking. I really think that will work ok for my 220 needs. But, can I run 2x 110 circuits off this same subpanel as well and be OK with the inspector? Obvously I will be limited to overall amp draw, but I don't think this will be an issue at any one given time.



-deon

 

[AKAMAC]

You can supply the sub-panel with any size breaker as long as the service entrance conductors are suitably sized. The aluminum conductors are the choke here. There are more electrical fires caused by (al) connections than by matches. There is no limit on branch circuits as long as the MAIN is sized correctly. You could theoretically feed a 200 amp panel with a 20 amp breaker and #12 wire and be legal.

If you want to do it right, you may have to work for it. ): Mike

 

[cap-n-cray]

AKAMAC, is right on. If you use the 30 amp 220V circuit use copper wire to run to the new shop. Be sure to use Noalox or some other aluminum to copper connectors. Aluminum wire tends to heat up with large draws. Drywall is easy to replace or repair. Only remove the drywall where you need to, fish the wire through the ceiling. You may be able to use double up breakers in the main panel to make room for another 220V breaker or replace the 30 amp breaker with a larger size with new wire. If your house is small you are probably not using 100 Amps. The over all load is important not the number of circuits. Some circuits can be combined. Do not use one breaker with two wire in it. Bring one wire out of the breaker and connect two circuits to that one wire. Always size the wire to the breaker's amp size.



Also what is more important a shop's power or your house's power?



Cary

 

[Alphacowboy]

Deon, if you dont have 200 AMP sercive at the main panel, you wont have 200 amp in the garage. At least if I am thinking right (half asleep right now) but hey, let me know if you need help with it... I have some tricky ways of running wires through finished areas! Do you have TGI or open trusses?

 

[DLausche]

Now I understand what you guys are telling me. I was concerned about running a 220 AND 110 circuits off of the new shop panel with the 220 30A feed. I understand now that I can more or less run as many circuits off of this subpanel as long as the total load is less than 30A which is the size of the main breaker that will feed this circuit. I am limited to 30A because of the 8 gauge AL feed wire. It would be nice to have more, but this will suffice and it isn't worth the effort to redo the ceiling in the basement. I'll run copper from the laundry room to the new shop and use the appropriate AL/CU connectors. I'm thinking now that I may not even need a subpanel at this junction and that just a good sized junction box will suffice. Can I put such a junction box up on the ceiling in the laundry room? This is the room where the furnace & water heater are as well and will never have a finished ceiling so it would always be accessible, even up between the floor joists.



Thanks for the info guys.



-Deon

 

[DLausche]

Deon, if you dont have 200 AMP sercive at the main panel, you wont have 200 amp in the garage. At least if I am thinking right (half asleep right now) but hey, let me know if you need help with it... I have some tricky ways of running wires through finished areas! Do you have TGI or open trusses?

Hi Matt. Good to hear from you again. The joists are all dimensional lumber - 2x10s. I finished the basement and I know there is absolutely no way we can fish new wire through from the existing main panel. I suppose I could run a conduit & wire up the outside of the house to the attic and from there over to the new garage. But, I think that a 30A circuit will be sufficient for my needs. I'll have to remember to give you a ring when I get to this job. It may not be until it warms up a bit outside.



-Deon

 

[Alphacowboy]

trust me, joists are not always as hard as you think to fish a wire through when its finished,, I have some tricks. . lol

 

[DLausche]

Well, I think I just figured out a way to get 200A of juice to my new shop/garage. How's that you ask? Well, the neighbors meter and distribution box is in the front corner of his garage - about 20 ft away from my garage. Now, I just need to figure out how to hook my wiring up and bury it so he doesn't see it and suspect something funny is going on.



Matt, I'll be calling you tommorrow to get your ideas on how to fish a new wire through.

 

[rbattelle]

There are more electrical fires caused by (al) connections than by matches.

What makes the aluminum wire so dangerous?



I recently ran a 30 amp 220 line out to my garage and have since learned that you can never have "too much" capacity, because now I've got to go redo it for a 35 amp air compressor I want.



Get this: the guy who built my house was apparently an electrical engineer. I have 2 (TWO) independent 200-amp main boxes in my house.



My dream shop: 600 amp 480/3 phase capacity, 400 amp 220/1 phase capacity, and 200 amp 120/1 phase. 1200 amp total capacity. Some day.



-Ryan

 

[TowPro]

splice into the line side of the meter and he will never know

 

[AKAMAC]

What makes the aluminum wire so dangerous?



I recently ran a 30 amp 220 line out to my garage and have since learned that you can never have "too much" capacity, because now I've got to go redo it for a 35 amp air compressor I want.



Get this: the guy who built my house was apparently an electrical engineer. I have 2 (TWO) independent 200-amp main boxes in my house.



My dream shop: 600 amp 480/3 phase capacity, 400 amp 220/1 phase capacity, and 200 amp 120/1 phase. 1200 amp total capacity. Some day.



-Ryan

Ryan, I wrote that tounge in cheek. "ELECTRICAL FIRES"

On a serious note; there is no longer aluminum wire in use in 10 gauge or smaller. The problem was electrolosis that occured at connections. The resulting resistance caused many a mobile home to spark-off. Aluminum was the wire of choice in the 60 and 70's.

The use of aluminum as large branch feeders (ovens/dryers) or service entrance conductors is still common practice. The larger area of wire surface and the use of antioxidents makes these uses safe.

My friend Ted lost his shop to al feeders. Called me on a Fri saying his welder was acting up. I said I would be up the next morning. He called Fri night to tell me the bad news.

Mike

 

[RT66DOC]

I have a 200 amp main in the house with a 70 amp breaker that feeds a 220V subpanel in the shop. The shop subpanel now feeds a 220V well pump and some 120V outlets. There's an unused 220V breaker in the subpanel which I will use for a compressor. I need to run more 120V stuff - lights and more outlets for power tools and think maybe I need a bit bigger subpanel. Is that 70 AMP breaker in the main box enough or should it be more? If it needs to be more, is it just a matter of replacing the 70 AMP breaker with a 100 or whatever?



TIA

 

[rbattelle]

If it needs to be more, is it just a matter of replacing the 70 AMP breaker with a 100 or whatever?

I don't believe so; that's what burns houses to the ground. You must ensure that the wiring on either side of that breaker (from the line into the box to the line out to the garage) is large enough to support the additional current safely.



-Ryan