power for the compressor

[kaptain howdie]

the other day I bought a husky 2 hp 30 gal compressor that draws approx 15a 110v. i want to run a dedicated line from my panel to the garage for it since that circuit is close to its max amperage.

now the main panel in the basement is very close to the garage wall, so running the wire will be easier than expected, but after looking at my panel today I have a couple of options.

I have a 30 amp breaker unused and a 60 amp 220v line for a dryer. I don`t have a dryer since my wife likes to hang our laundry so the breaker is off and the outlet is not used.

so i want to use a sub panel but i`m not sure if I should use the 30a circuit, or the 60a 220. I could split the 30a to 2 15`s in the sub box, or use the 220.

the question is if i use the 220v and run it to a sub panel, how do you convert it to 110? I would prefer this option since I will probably be getting a small welder in the future and could use the extra power.

thanks in advance.

 

[Sureshot]

Sounds like you better get some help before you get an afro.

 

[kaptain howdie]

Sounds like you better get some help before you get an afro.

never installed a sub panel before, so just looking for some advise rather than sarcasm.

 

[Jim Johnstone]

Where in Ontario are you located? If you're near Brantford I'd be happy to help or at least show you how I did mine. I would suggest going to Home Depot or Lowes and pick up a good wiring book, it will really go a long way.

The jist of it is that the 240 volt service is created by using two 120 volt lines on different phases from one another. If you look at your panel, a 240 volt breaker is twice as big and will have two hot lines coming off of it. A 120 volt breaker only taps off of one line and has one wire coming off of it.

 

[nehog]

never installed a sub panel before, so just looking for some advise rather than sarcasm.

The poster's advice was not sarcasm, your questions indicate that you need more assistance than you can get from an Internet forum.

 

[phbsales]

I agree that the OP is going to need some electrical expertise with this.

My main concern is that he's going to run a 60 amp sub-panel from the dryer breaker out to his garage and overload the panel. 110v, 15 amp air compressor doesn't bother me much, but the 230v welder is going to present a problem. I would do some research as to what kind of amperage a welder draws versus the 60 amps he has available to him. If it's 45 amps or above, I'd scrap the idea. That's an electrical fire just waiting to happen, because the panel is already maxed-out.

 

[Jim Johnstone]

I agree that the OP is going to need some electrical expertise with this.

My main concern is that he's going to run a 60 amp sub-panel from the dryer breaker out to his garage and overload the panel. 110v, 15 amp air compressor doesn't bother me much, but the 230v welder is going to present a problem. I would do some research as to what kind of amperage a welder draws versus the 60 amps he has available to him. If it's 45 amps or above, I'd scrap the idea. That's an electrical fire just waiting to happen, because the panel is already maxed-out.

How is that an electrical fire waiting to happen? If he uses the right wire (#6 I believe) for the 60 amp breaker, there is no more of a fire risk than the lights over my head being fed by #14 on a 15 amp breaker.

The worst that happens is he overloads the panel and trips the breaker.

I would also be willing to bet that there are a lot of guys on here that weld in a garage that is powered by a 60 amp panel.

 

[phbsales]

How is that an electrical fire waiting to happen? If he uses the right wire (#6 I believe) for the 60 amp breaker, there is no more of a fire risk than the lights over my head being fed by #14 on a 15 amp breaker.

The worst that happens is he overloads the panel and trips the breaker.

I would also be willing to bet that there are a lot of guys on here that weld in a garage that is powered by a 60 amp panel.

You may be correct, but personally I wouldn't do it, not DIY anyway. I'd feel better having my electrician doing it and balancing out the load.

 

[Falcon67]

I would also be willing to bet that there are a lot of guys on here that weld in a garage that is powered by a 60 amp panel.

My old shop was on a 60A feed and included welding, AC, heat, milling, lathe, lotsa misc other power tools. Never had a breaker trip. I had 12 circuits out of a "125A" sub panel, balanced pretty well I think.

60A sub is no big deal IMHO, but the OPs question about how to split it into 120V circuits and thinking its possible to "split" a 30A 120V circuit into two 15As indicates more reading/research or a call for professional services.

 

[Jim Johnstone]

60A sub is no big deal IMHO, but the OPs question about how to split it into 120V circuits and thinking its possible to "split" a 30A 120V circuit into two 15As indicates more reading/research or a call for professional services.

Agreed, I think the first stop for the OP should be Lowes or H.D. and pick up a good book on house electrical and read that through before trying to install this himself.

 

[Sureshot]

The poster's advice was not sarcasm, your questions indicate that you need more assistance than you can get from an Internet forum.

Sorry it came off as sarcastic but it sounds like you need some help or some basic knowledge before attempting this job. It is an "advanced" DIY job and has some possible serious outcomes.

 

[kaptain howdie]

I agree that the OP is going to need some electrical expertise with this.

My main concern is that he's going to run a 60 amp sub-panel from the dryer breaker out to his garage and overload the panel. 110v, 15 amp air compressor doesn't bother me much, but the 230v welder is going to present a problem. I would do some research as to what kind of amperage a welder draws versus the 60 amps he has available to him. If it's 45 amps or above, I'd scrap the idea. That's an electrical fire just waiting to happen, because the panel is already maxed-out.

i don`t believe i mentioned that the welder would be 230v, my needs would be for a small 120v unit.

the sub panel i have is rated for 60 amps and is a 3 wire unit. i was reading on the net that sub panels should use 4 wire. this is where i`m confused since i`m assuming that the 3 wire might not meet code.

the job doesn`t seem to be that complex, and i would prefer to do this myself.

 

[nehog]

Well, if you prefer to do it yourself, I'd suggest going to the local library and seeing what books they have regarding residential wiring techniques. If the library doesn't have a good one, then hit a better book store, it will make a good investment. Finding a friend who has more experience can be helpful too, if only to review what you are doing and point out errors (like putting light switches on the white wires instead of the black ones...)

 

[kaptain howdie]

the questions i need answers for are:

I have a 2 pole 60 amp breaker for the dryer, can i use that wire for a sub panel, or do i have to upgrade it? (keeping in mind that the wire is old, not even sure what gage it is.

if i upgrade the wire, do i get 3 or 4 wire which would mean that i have to buy a new sub panel?

 

[Milton Shaw]

You should be able to buy a ground bar to add to the 3 wire panel and then run all the ground wires to that ground bar. The existing neutral bar in the 3 wire panel should not show connection to the box. You may have to remove a bonding screw if the box shows connection. This screw is just a longer screw in the box that goes from the insulated neutral bar to the metal box. Remove it. Get the 4 wire to run from existing box and get a book and read up on this before you mess with anything in that box

 

[kaptain howdie]

whats the purpose of the extra wire? i`m assuming that if the box was originally designed for 3 wire the 4th now is new code?

 

[Charles (in GA)]

You should be able to buy a ground bar to add to the 3 wire panel and then run all the ground wires to that ground bar. The existing neutral bar in the 3 wire panel should not show connection to the box. You may have to remove a bonding screw if the box shows connection. This screw is just a longer screw in the box that goes from the insulated neutral bar to the metal box. Remove it. Get the 4 wire to run from existing box and get a book and read up on this before you mess with anything in that box

Most sub panels, to make them cheaper, give you an insulated ground/neutral bar, and do not give you a straight ground bar. As noted, you have to buy the ground bar separately and screw it in. If you get the same brand bar (which you are supposed to do) the panel will have holes that will line up with holes in the ground bar, and you can screw it hard to the panel. The insulated "ground" bar is used for a neutral and also as noted, should not be electrically connected to the panel cabinet. If it has a long green screw run down thru it and thru the back of the panel, you need to remove this screw, or if it has a copper lug sticking out of a terminal on it and screwed to the panel, you need to remove it. Depends on the brand as to how they make this connection, but you need to un-do it if it is there.

Charles

 

[kaptain howdie]

just went through the ontario code book and in relation to sub panel installation there is no mention of a 4th wire. just the 2 for the main bus, common and ground. it also states that there is no regulation for the size of wire used for the sub panel but mentions that you SHOULD use the common rule of thumb for sizing.

its a 2006 edition.

 

[Jim Johnstone]

The 4th wire depends on where you are putting the panel, and how close to the main panel it is going to be. You can use 3 wires, keeping the ground and neutral bonded in the sub panel, and then ground at the site of the sub, which is what I did. Or if you are close enough with easy access to the main panel, use 4 wires, isolate the ground/neutral and it will just be a little easier and cleaner.

And there is certainly wire size regulations, for 60 amps, you need at least #6 wire. The code book should outline that for you as well.

 

[justsam]

just went through the ontario code book and in relation to sub panel installation there is no mention of a 4th wire. just the 2 for the main bus, common and ground. it also states that there is no regulation for the size of wire used for the sub panel but mentions that you SHOULD use the common rule of thumb for sizing.

its a 2006 edition.

I think you answered your own question, there are two hot wires, one neutral, and a ground, for a total of FOUR wires. Not sure what code is in Canada, but as Jim Johnstone pointed out, it can be done with three or four wires, depending on local code requirements.

In regard to wire size, look up AMPACITY, which will help you determine the proper wire size. There is no one regulation since it depends on load current, or AMPS.

How large is your main panel, is it a 200 AMP panel? Also the existing DRYER breaker you stated is 60 AMP. That seems stout, should be more like 30 AMP if it indeed was intended for a dryer. May work out great for you however if you install a 60 AMP sub panel, which is the way to go.

I don't know your welding requirements, but most outgrow a 115VAC unit, and you will want the 240 VAC, for use in your shop with a compressor, plasma cutter, etc., etc.

 

[kaptain howdie]

I think you answered your own question, there are two hot wires, one neutral, and a ground, for a total of FOUR wires.

How large is your main panel, is it a 200 AMP panel? Also the existing DRYER breaker you stated is 60 AMP. That seems stout, should be more like 30 AMP if it indeed was intended for a dryer.

don`t think you count the 4th wire as ground. my main is 200 service, and the dryer line is 60 amp, 2 30`s with a tie bar.

 

[Falcon67]

You have two hot leads, one neutral which is power return to the service and one bare copper or green insulated that is intended to be the safety ground. The neutral and safety ground must stay separate until they reach the service entrance - your main box.

 

[kaptain howdie]

i`m just thinking it is strange to have a dryer circuit on 60 amps since it usually 30. i`m going to doulble check it again...................................

 

[Jim Johnstone]

don`t think you count the 4th wire as ground. my main is 200 service, and the dryer line is 60 amp, 2 30`s with a tie bar.

If it's two 30's with a tie bar, then it's a 30 amp 2 pole breaker, not a 60.

And yes, the ground is counted as a 4th wire.

 

[kaptain howdie]

If it's two 30's with a tie bar, then it's a 30 amp 2 pole breaker, not a 60.

And yes, the ground is counted as a 4th wire.

don`t know why i was adding the 2 breakers together, shows how much i know.

nonetheless, i finished the job this weekend. i ran 8/3 off a 30 amp 220 circuit for an old heater in my rec-room in the basement that`s not being used. (left the dryer alone). installed the panel, and ran 14/2 to my compressor on a 15amp breaker. I have a 220/20amp extra breaker in the box just in case a get a welder in the future, all i have to do is put a 40 amp breaker in the main.

thanks for everyone`s help.