# Run wires for 220v outlets or add a sub-panel in the garage?



## afx (Feb 5, 2010)

I need a 220v outlet in my garage for a compressor I'm planning on purchasing. My breaker box is outside of my house about 10 feet from the right wall of my garage. I thought about running some 10/3 wire to a 20amp breaker and dropping it in my wall which is a pain in the butt.

Another option I was thinking would be to run some 8/3 wire outside the breaker box, down the side of the house, then punch through that wall and install a sub panel with a 50amp breaker where I can add a few 220v outlets and several 110 outlets (my garage only has 1 outlet in it!)

Just bouncing ideas around to see what you guys have experience with.

Thanks!

Here is a drawing of the second option.


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## rrich (Jun 24, 2009)

You don't say where you are, geographically.

First option is conduit from the current box to the garage along the outside wall. Then a subpanel in the garage.

If you have access (crawl space or basement) run the wire to the garage inside the house and install a sub panel. Both easy and not very expensive.

HOWEVER

You probably need 4 slots that can be used in the existing circuit breaker box. I'm thinking 100 to 200 amps in the garage and these breakers are usually wider than the normal 220 volt breakers. 

If you have more than 2 slots open in your current breaker box, the builder was throwing money away. (At least in their mind set.) 

In reality, you're probably going to have to replace the existing circuit breaker box. This is both good and bad. With a new box you'll have access to the inside of the wall and installing the wire to the new sub panel is much easier. 

The bad is weather proofing and permits. Your electric company won't disconnect and reconnect the power without you having a permit. If you do the disconnect / connect process yourself, the electric company won't do the final reconnect without a permit.

While a 50 amp panel might barely suffice today the big question is, what happens if your compressor starts while your table saw and dust collector are running? If it were me, I wouldn't put anything in less than 100 and preferably 200 amps. You don't have enough power out in the garage now and for a shop you're going to need more than the 50 amps.


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## afx (Feb 5, 2010)

rrich said:


> You don't say where you are, geographically.
> 
> First option is conduit from the current box to the garage along the outside wall. Then a subpanel in the garage.
> 
> ...


I'm in Houston so no crawl space unfortunately  The wires go up into the attic and run along the rafters to their designated drop points. As for how much amperage I would need, I really think 50 amps would be sufficient, my table saw is 110 and runs on a different breaker, the only other 220v item I would have in my garage would be a dust collector and I can't see a compressor and dust collector pulling more than 50 amps at high load. As for the number of available busbar slots, I believe I have 8 available (it could be 4). I wouldn't do any of the above ideas if I needed to add a new breaker box. Too much cost.


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## woodnthings (Jan 24, 2009)

*the cost is really the labor*

I would run the new wiring outside in a conduit, appropriate for the size of the sub panel. I would have a minimum of 60 Amp sub, better yet, a 100 Amp. The difference is a one time expense, probably less than $100.00 in material/parts. Now you have an upgraded system for the next generation. As you stated each 220 breaker requires two slots, so you can use up a smaller panel in a hurry. A compressor, then a 3 HP saw, then a 50 AMP welder, then a 3 HP planer.... etc. Several 110 V runs for corded tools like a drill press or belt sander, are a blessing also. The lights should be on their own circuit for safety reasons, should a tool trip the breaker at night. You would be in the dark trying to find a door,a breaker switch etc. 

I filled a 100 AMP sub in my woodshop with many dedicated circuits although they are never used more than 2 at a time, like the Dust Collector and table saw or planer. You asked for advice in general, the "whys", not "how to wire it". Of course you should get a licensed electrician to perform the actual work. 

For the record, I have 5 -100 AMP subs in my house, 2 shops and the garage.... 400 AMP service in., with 2 mains, a 225 AMP and a 175 AMP. You can't have too many AMPs, HP, or too much AMMO, just sayin". You only use what you need at the moment. :yes:


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## cabinetman (Jul 5, 2007)

It might be to your benefit to get information like that from a real electrician that is standing right there in front of you, not from forums. He/she would have the opportunity to view your electrical conditions, and give advice based on his professional expertise, knowledge of local codes, and an onsite evaluation. 

Making decisions or following the advice you get from members of a woodworking forum, or any forum for that matter is just not wise. You will get information and suggestions that don't even coincide with each other. While many of the suggestions are in good faith from those that think their methods and advice is correct, and some may even be electricians, while others are wannabe's, you have no idea how accurate their advice really is. With what's at stake, like the possibility of having a fire, shock, death, or voiding your homeowners insurance, is it worth getting information from anyone on the internet?

My suggestion is to have a consultation with a licensed electrician familiar with your needs, make an onsite inspection of the conditions to offer an evaluation and make suggestions. It might even be free.

I wouldn't give any credibility to those that offer electrical or structural suggestions. What they do to their property is their choice, whether it's right or wrong. It would be more impressive if they offer woodworking advice.:yes:

















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## Fred Hargis (Apr 28, 2012)

The sub panel is going to be far better than running a single circuit.. As somone mentioned, the cost of upsizing it from 50 amps is really minimal, but 50 amps may well be sufficient for your planned use. When we bought this house, the building (a detached garage) that was to become my shop had 50 amps of service. I upgraded it to 100 amps before we moved in. Actually, I had it done since working with the heavier wire is something I always hire out.


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## woodnthings (Jan 24, 2009)

*just my opinion here*

I think a woodworking forum is great place to ask for advice where folks with actual woodworking machine knowledge and experience.

They will know the various types and capacities in HP and amperage requirements. For example take the "planer" which type? Lunch box running on 120V or a 15" 3HP running on 220V. If you don't specify which type you will end up without the proper circuit. Same for a table saw. Which type? Bench top/jobsite saw runnning on 120V or Hybrid with a 1 3/4 HP on 120V or a 3 HP cabinet saw running on 220V, each requiring a different circuit and wiring. Same with a bandsaw. Which type? A 10" with a 1/3 Hp motor, a 14" with a 1 HP motor or a 18" with a 3 HP 220v motor. And in the case of an air compressor, which type? A 2Hp or 3 HP portable model on wheels, a stationary 4 Hp or 5 HP on 220V? There are a lot of variables in a machines used in a woodshop.

How many machine will be running simultaneously? Maybe the compressor will come on when the table saw is running or the dust collector and planer are running at the same time. An electrician may not not know those potential combinations, but as woodworkers we do.

A licensed electrician may know the codes and the wiring requirements, but may not have specific knowledge of how to set up a woodworking shop unless he is a "licensed" woodworker....
The OP asked for opinions and is free to ignore any or all of them.:yes: I'm pretty sure he can find a licensed electrician if and when that is relevant, but at this point it's just a discussion in a woodworking forum... that's what we do here, discuss things based on our own experience and knowledge. We shouldn't be giving recommendations for wiring sizes and lengths of runs and which brand of circuit breakers and thermal overloads to use. :no: That where the licensed electrician comes in and asks "How many circuits and what size are they?" And because you have become an informed home owner you will get the best results... just sayin'


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## Steve Neul (Sep 2, 2011)

Before you do anything be sure to make sure you are legally able to do the wiring work yourself. The government in many areas is getting picky on any modifications to the house whether it's done textbook correct or not. Being in Houston I would suspect you can. If it were me I would opt for the sub-panel. It would cost a little more but I think it would be worth it.


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## cabinetman (Jul 5, 2007)

woodnthings said:


> I think a woodworking forum is great place to ask for advice where folks with actual woodworking machine knowledge and experience.
> 
> They will know the various types and capacities in HP and amperage requirements. For example take the "planer" which type? Lunch box running on 120V or a 15" 3HP running on 220V. If you don't specify which type you will end up without the proper circuit. Same for a table saw. Which type? Bench top/jobsite saw runnning on 120V or Hybrid with a 1 3/4 HP on 120V or a 3 HP cabinet saw running on 220V, each requiring a different circuit and wiring. Same with a bandsaw. Which type? A 10" with a 1/3 Hp motor, a 14" with a 1 HP motor or a 18" with a 3 HP 220v motor. And in the case of an air compressor, which type? A 2Hp or 3 HP portable model on wheels, a stationary 4 Hp or 5 HP on 220V? There are a lot of variables in a machines used in a woodshop.
> 
> ...


I disagree. My suggestion was..."My suggestion is to have a consultation with a licensed electrician familiar with your needs..."

That professional will know how to advise. Giving advice may sound impressive, but codes, laws, conditions, and materials may differ from area to area. I've set up many shops from the ground up, but I'm no electrician, and know better than to give electrical advice.

When dealing with a professional, all the parameters are given, tools and machines that are in question, and that's what provides the basis for evaluation. If you have an electrician that's not familiar with tools and machinery or how to set up a shop, I suggest you find another one. If the OP does arrange a consultation, and states what he learned on a forum, and I was the electrician, I'd be headin' out.:yes:

















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## woodnthings (Jan 24, 2009)

*the key phrase is*

.... have a consultation with a licensed electrician "familiar with your needs" and the OP will not know what his "needs" are until he is informed. That's the purpose of this thread, unless I'm mistaken. :blink:


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## cabinetman (Jul 5, 2007)

woodnthings said:


> .... have a consultation with a licensed electrician "familiar with your needs" and the OP will not know what his "needs" are until he is informed. That's the purpose of this thread, unless I'm mistaken. :blink:


He may not but the electrician should. But at least you got a chance to talk about all your amps.:laughing:








 







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## MatthewEOD (Dec 6, 2013)

I would look at my ultimate goal and then contact an electrician. The I could talk intelligently with an electician to work out attainable goals for my electrical system. Even if I cant spell


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## Steve Neul (Sep 2, 2011)

I can't see that a electrician or who ever does the wiring needs to be a woodworker. AFX should know what machines that might be used at once and each has a amp rating. It just comes down to math to provide the amps for each circuit. The only exception would be the compressor. They draw so much power at start up I would have a dedicated line just for it.


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## Toller (Dec 30, 2007)

I ran two new circuits for my shop, and when I needed a third, I ripped the first two out and put in a subpanel.
Sure wish I had put in a subpanel first.

I ran 6/3 for a 60a sub, but used a 30a breaker since I had one on hand. That turned out to be all I ever needed, so I never bought a larger breaker.
Yeah, if your compressor comes on when you are using other tools, you will have a problem, so just don't do it.
I found 30a was enough for any two tools I had, and I never used more than two at once.
Now I had no tools over 3hp; if you have larger tools than obviously 30a won't work for you; but unless you are also heating the shop or having other people working with you, it is hard to see how you might need 100a.


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## afx (Feb 5, 2010)

Hey guys thanks for the awesome info. I don't mind the folks saying I need to get an electrician out. Electricity is one of those subjects that unless you know the person well, you have to assume they aren't qualified to work on it. The dangers of messing with this stuff could mean my next woodshop will only be 7 feet by 2 feet, made of wood, and 6 feet in the ground.... No one wants that (RIGHT?!) 

I think I'm going to take everyone's advice. My neighbor is an electrician, however I've never been too chatty with him, honestly I think I've only talked to him 5 times in the 6 years I've been his neighbor. Maybe I'll catch him outside one day and throw a few questions his way, possibly a few bucks too. I think I've settled on running a sub-panel to the garage because I can run the wire outside with relatively little disturbance in the look of the side of my house. I also think I'll be wiring a 100 amp main just in case I need it later on (although I don't think I will). I just have to find a good supplier of 4AWG wire that isn't going to try and empty my wallet. Probably another good question to ask the neighbor. Depending on the price though, I might be forced to drop the amperage down somewhat. 

Thanks again guys!


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## Steve Neul (Sep 2, 2011)

I think 100 amps is a bit much for a garage shop. You could have a 5 hp air compressor running at the same time you are welding at night with all the lights on and have juice left over. Chances are the most you would draw at one time is 40 amps. Just add up all the equipment you could conceive have running at the same time and see what you need. Also include the equipment on your wish list. The lights are listed as watts. Since they are on 120 volts divide the watts by 120 to get the amperage.


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## woodnthings (Jan 24, 2009)

*It's not a 100 AMP draw*



Steve Neul said:


> I think 100 amps is a bit much for a garage shop. You could have a 5 hp air compressor running at the same time you are welding at night with all the lights on and have juice left over. Chances are the most you would draw at one time is 40 amps. Just add up all the equipment you could conceive have running at the same time and see what you need. Also include the equipment on your wish list. The lights are listed as watts. Since they are on 120 volts divide the watts by 120 to get the amperage.



It's a 100 AMP panel and that will have enough slots to allow for as many circuits as you will ever need. The 100 AMP load center will have it's own breaker, 100 AMPs, and that will control the current draw through the panel, and you will never trip that breaker. The reason for getting that large a panel is to have enough empty slots, not because you will draw 100 AMPS. :no:

Cheap also:
http://www.ebay.com/itm/SQUARE-D-100-A-LOAD-CENTER-PANEL-AMP-HOMELINE-BREAKERS-/181078044770


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## tvman44 (Dec 8, 2011)

You need 6-3 with ground for a 50 amp breaker. I would run the 6-3 with ground and a 50 amp breaker and sub panel in the garage. Better yet would be a 100 amp circuit while you are at it. :thumbsup:


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## cabinetman (Jul 5, 2007)

*Advice for afx*

It's obvious you're getting different opinions, and a variety of "expert" answers. I wouldn't pay much attention to which one is valid or not, but they keep on coming.:laughing:

You would likely do best with a casual talk with your neighbor. You said you two weren't buddy buddy, but he's still your neighbor, and would probably help you out.


















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## Tom King (Nov 22, 2013)

When buying heavy wire by the foot, dig your ditch, run your conduit, or whatever you are going to do, set the sub panel, then measure to see how much wire you need to buy. It's MUCH better to have 2 or 3 feet to throw away than to come up short.


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## ryan50hrl (Jun 30, 2012)

How many amps is your main panel?


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## rrich (Jun 24, 2009)

Steve Neul said:


> I think 100 amps is a bit much for a garage shop.


 Steve,
The panel that I had added to my garage shop is fed by a 100 amp drop and there are 190 amps of breakers in use, all for the shop. I have one double slot left. In addition, the lights are on a totally separate circuit.


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## Steve Neul (Sep 2, 2011)

woodnthings said:


> It's a 100 AMP panel and that will have enough slots to allow for as many circuits as you will ever need. The 100 AMP load center will have it's own breaker, 100 AMPs, and that will control the current draw through the panel, and you will never trip that breaker. The reason for getting that large a panel is to have enough empty slots, not because you will draw 100 AMPS. :no:
> 
> Cheap also:
> http://www.ebay.com/itm/SQUARE-D-100-A-LOAD-CENTER-PANEL-AMP-HOMELINE-BREAKERS-/181078044770


 I guess so but he shouldn't connect a 4 guage wire to a 100 amp breaker. 4 guage wire is only rated for 60 amps if aluminum or 70 amps if copper.


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## Noek (Jan 26, 2013)

Scary notion having a breaker you will never trip. 

Have a licensed/insured professional do your electrical work. 

It's okay to get peoples opinions and ideas, but when it comes down to it, your insurance company covers your house, not the people on this forum.

Just my .02


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## Fred Hargis (Apr 28, 2012)

rrich said:


> Steve,
> The panel that I had added to my garage shop is fed by a 100 amp drop and there are 190 amps of breakers in use, all for the shop. I have one double slot left. In addition, the lights are on a totally separate circuit.


Actually, it's not the total of the breaker amps that determine anything. I'd be very surprised if most houses didn't have the breakers add up to more than the panel they're in. It's the load those breakers carry under normal use that's important, and that's less than the sum of the breakers.


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## woodnthings (Jan 24, 2009)

*some understand, some don't*



woodnthings said:


> It's a 100 AMP panel and that will have enough slots to allow for as many circuits as you will ever need. The 100 AMP load center will have it's own breaker, 100 AMPs, and that will control the current draw through the panel, and you will (PROBABLY) never trip that breaker. The reason for getting that large a panel is to have enough empty slots, not because you will draw 100 AMPS. :no:
> 
> Cheap also:
> http://www.ebay.com/itm/SQUARE-D-100-A-LOAD-CENTER-PANEL-AMP-HOMELINE-BREAKERS-/181078044770





Noek said:


> Scary notion having a breaker you will never trip.
> Just my .02





Fred Hargis said:


> *Actually, it's not the total of the breaker amps that determine anything*. I'd be very surprised if most houses didn't have the breakers add up to more than the panel they're in. It's the load those breakers carry under normal use that's important, and that's less than the sum of the breakers.



IF you *ever *trip the main panel breaker, 100 AMP for this discussion, You either have a MAJOR short circuit, or you turned on very light, power tool, compressor, and electric heater in the shop, very unlikely. :yes: As Fred says above, the sum total is often more than the rated capacity of the panel, and can be because all the tools are never used simultaneously or turned on all at the same time....... :no:

ALWAYS CONSULT A LICENSED ELECTRICIAN BEFORE PERFORMING ANY WORK OR CHANGES ON YOUR ELECTRICAL SYSTEM.... there I've said it for the umpteenth time. :yes:


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## Alchymist (Jan 2, 2011)

woodnthings said:


> It's a 100 AMP panel and that will have enough slots to allow for as many circuits as you will ever need. The 100 AMP load center will have it's own breaker, 100 AMPs, and that will control the current draw through the panel, and* you will never trip that breaker.* The reason for getting that large a panel is to have enough empty slots, not because you will draw 100 AMPS. :no:
> 
> Cheap also:
> http://www.ebay.com/itm/SQUARE-D-100-A-LOAD-CENTER-PANEL-AMP-HOMELINE-BREAKERS-/181078044770





Steve Neul;565814[B said:


> ]I guess so but he shouldn't connect a 4 guage wire to a 100 amp breaker. 4 guage wire is only rated for 60 amps if aluminum or 70 amps if copper.[/B]





Noek said:


> *Scary notion having a breaker you will never trip. *
> 
> Have a licensed/insured professional do your electrical work.
> 
> ...


So much mis -information here- amazing. woodnthings comment is right on, a 100 amp breaker in a sub-panel fed by a smaller breaker in the main panel WILL NOT TRIP. The smaller breaker in the main panel will trip first.

The 4 gauge wire mentioned above can be safely connected to a 100 amp breaker in a sub-panel. What determines the protection for the wire is the breaker feeding it, NOT the breaker it is feeding. So, it's not necessarily "scary" to have a breaker that will never trip. Depends on the circumstances.

Lots of posting here by people who only know part of the story. That's the scary part.


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## Noek (Jan 26, 2013)

Alchymist said:


> So much mis -information here- amazing. woodnthings comment is right on, a 100 amp breaker in a sub-panel fed by a smaller breaker in the main panel WILL NOT TRIP. The smaller breaker in the main panel will trip first.
> 
> The 4 gauge wire mentioned above can be safely connected to a 100 amp breaker in a sub-panel. What determines the protection for the wire is the breaker feeding it, NOT the breaker it is feeding. So, it's not necessarily "scary" to have a breaker that will never trip. Depends on the circumstances.
> 
> Lots of posting here by people who only know part of the story. That's the scary part.



I'm not an electrician, but I am an electrical journeyman lineman for a large utility in Southern California and the possibility of having fusing or breakers that don't open is a scary notion. It generally means you're making fire or glass somewhere. 

Maybe it was a bad notion to relate the two  I'm one of the ones who only know part of the story which is why I have always used a licensed contractor to split the load and install new circuits for me.

It's still a scary notion.


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## woodnthings (Jan 24, 2009)

*It's a misunderstanding here*



Noek said:


> I'm not an electrician, but I am an electrical journeyman lineman for a large utility in Southern California and the possibility of having fusing or breakers that don't open is a scary notion. It generally means you're making fire or glass somewhere.
> 
> Maybe it was a bad notion to relate the two  I'm one of the ones who only know part of the story which is why I have always used a licensed contractor to split the load and install new circuits for me.
> 
> It's still a scary notion.



No one is saying it *can't trip*, just that it probably won't.... and only under the most extreme conditions... a full 100 AMP + overload due to a short circuit OR 100 AMPS + of draw from the tools/appliances. The other point made is that the smallest breaker will trip first, at least in theory and if everything is working it should.
If the smallest breaker is ahead of the subpanel, in the main, then that should trip before the sub. I think we can agree on that. :yes:


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## Civilian (Jul 6, 2013)

cabinetman said:


> You would likely do best with a casual talk with your neighbor. You said you two weren't buddy buddy, but he's still your neighbor, and would probably help you out.



Plus the neighbor might feel like charging for his services instead of doing it as a favor. I would rather pay for his knowledge and services when it comes to electrical panels. Maybe he can tell you (after he sets the panel) how to run the circuits and still be within code requirements.

Jon
Northern Michigan


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