Questions regarding 220

[Rob Hough]

Over the weekend I scored a Grizzly 2HP D/C that requires a 220v line. Unfortunately for me I do not have a 220v outlet in the garage (where blossoming little shop resides) so I'll need to get one added. This looks like a task I can easily tackle myself but I've got some questions.

Sounds like a great idea to me actually...I read somewhere on here a similar affair. One of the suggestions was running a sub-panel off the primary, and then put all of my shop circuits on that.This sounds like a great idea. We have 200amp service. Would I need to get that upgraded?

The main panel has 6 free slots. I was planning on adding 2 220v outlets and some additional 110's for another room we are adding.

Next question is regards to the tools themselves. I have a couple of tools that can run 110 or 220. Would I benefit from much by converting them all to 220, or should I just leave them as is?

[Paul Ryan]

Rob,

If you have a 200 amp service to your whole place that is plenty. But I would sub off a 2nd panel for your shop. That is really easy, all you need to do, is add a 60 amp breaker in your current panel, and run 8 guage wire to the new panel in the shop. Double check the wire size with your local store I think 8 copper or 6 aluminum will work for 60 amps. Pick a panel that will have plenty of slots for you. You dont necessarily have to use a 60 amp panel. A larger panel will have more slots. The panel I have in my shop has 16 slots total. You can run 60 amps to a 100 amp panel with out any danger. It is still the breaker in the house box that is protecting that panel. 60 amps for your shop should be more than enough. There are still lots of houses that only have a 60 amp service. Once you have the sub panel added then you can add your 220 and 110 outlets off of that panel, and save the 4 other slots in your house box for other circuits in the house.

As far as changing your current tools over to 220 the only thing that would do for you is allow the motors to run cooler. The larger voltage uses less amps to produce the same wattage. It wont save you any money or give the tools more power. It just may let the motors last a little longer.

[Rob Hough]

Thanks. I was starting to lean in that direction but wasn't entirely sure how much more additional work it would be. Now to get the garage cleaned up so I can turn it into a shop. :)


Thanks to whomever relocated my post to the right place.

[John Morrison60]

Rob

You can certainly add a sub panel to a 200 amp service entrance panel.

There are some requirements as far as isolating the "ground bar" from the "neutral bar".

I would encourage you to begin only installing duplex (two breakers in same space as one) breakers in your main box.
That buys you space that you will ultimately need.

If you pull 50 - 80 amp service over to your garage sub panel,
you should have enough for most anything you need in the shop.
The amount of service that you have in your garage will probably be driven by the size of the wire that you install.
The lower guage (but larger) wires are quite costly per foot.

You will just pull a four wire cable -- two hot leads, one neutral, one ground, to your sub panel. and go.
I have adopted a 1.5 hp rule on tools. If it is 1.5 HP or greater,
then I try to change it to 220.
I run my cyclone and my Table Saw at 220,
everything else in my small shop runs off of 110.
Not saying this is right. but unless you are constantly turning them on/off or running long duration, 220 may be overkill for many tools.

Good Luck
Fun projects
John

[Chris Padilla]

Rob,

all you need to do, is add a 60 amp breaker in your current panel, and run 8 guage wire to the new panel in the shop. Double check the wire size with your local store I think 8 copper or 6 aluminum will work for 60 amps.

Definately check on this. I'm pretty sure #8 THHN is NOT big enough for 60 A. I think it is only good enough for 40 A. I ran #6 NM (romex) for a subpanel and it is protected with a 50 A breaker.


As far as changing your current tools over to 220 the only thing that would do for you is allow the motors to run cooler. The larger voltage uses less amps to produce the same wattage. It wont save you any money or give the tools more power. It just may let the motors last a little longer.

The motor doesn't care if you run it at 240 V or 120 V and it won't run any differently. The only difference is that you are drawing less current through the wires in the wall and thus have a bit lower power loss (voltage drop) in wall wires and less heat in the wall wires. This may deliver slightly more current to the motor thus making it appear to "start more easily" or "have more power".

[Tom Veatch]

... One of the suggestions was running a sub-panel off the primary, and then put all of my shop circuits on that.This sounds like a great idea. We have 200amp service. Would I need to get that upgraded?

Probably not. The main breaker rarely if ever is as large as the sum of all the branch circuit breakers.



The main panel has 6 free slots. I was planning on adding 2 220v outlets and some additional 110's for another room we are adding.

Are these in addition to the subpanel for the shop? Each added 220 circuit usually needs 2 of those slots and you'll need 2 for the breaker that feeds the subpanel. There may be reduced height double pole-common trip breakers available to give you a 220 circuit out of a single slot, but I've never used any and wouldn't count on it. Perhaps the upgrade will free one or more existing slots that can be reused. There are half height dual breakers that will give you 2 110 circuits out of a single slot.



Next question is regards to the tools themselves. I have a couple of tools that can run 110 or 220. Would I benefit from much by converting them all to 220, or should I just leave them as is?

There's a lot of controversy on that subject, but the fact is that most installations will see no noticeable benefit from going to 220v. But, depending on the particular circumstances, there are a few that will, and since there is no downside from going to 220, that's what I would do in your situation. In fact, what I would do is wire the shop circuit with 20 amp 12ga 4 wire (2 hots, neutral, and ground) cable and use a dual voltage 20 amp receptacle at each outlet to get both 110 and 220 at each drop. That gives you the maximum versatility.

There's also a lot of controversy about what size circuit(s) to run. But the fact of the matter is, assuming a single user shop, unless you have a strong suspicion that you're going to be running something greater than 3-4 HP in the future, 20 amp 12 ga circuit(s) will meet the needs of a single user shop quite well. One alternative is to run 10ga in anticipation of going to a 30 amp circuit later. Your choice, but not the one I would make unless I was fairly sure I'd need the 30 amp circuit at some point in the future.

Keep in mind that with the 30 amp circuits, the receptacles MUST also be 30 amp which means that all the plugs on your tools will also have to be 30 amp plugs. Certainly doable, but a PITA if you don't need the 30 amps. Likewise the 10ga wire is a much bigger pain to work with than the 12ga. If you use it, use the larger boxes. Don't even think about trying to use the little single width receptacle/switch boxes.

[Paul Ryan]

I just checked the wire going to my shop. It is 4 AWG aluminum for 60 amps. So my first thought on wire size was wrong as far as I know if it is 4 alu. 6 copper would work, but copper is about 3 times the money.

[Rob Russell]

That is really easy, all you need to do, is add a 60 amp breaker in your current panel, and run 8 guage wire to the new panel in the shop. Double check the wire size with your local store I think 8 copper or 6 aluminum will work for 60 amps.

Whether you're running NM-cable or THHN/THWN in conduit, you'd need either #6 copper or #4 aluminum to feed a 60-amp subpanel. Table 310.16 is the source, plus a whole bunch of other rules that determine which column you can use.

Rob
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