New 230 Circuit

[Mike Holbrook]

I am running a new circuit to my shop, well actually two new dedicated circuits, one 120, one 230. Is 20 amps for 120 and 30 for 230 enough? I want to get it right this time.

I have no 230 equipment now, although my General contractor saw could be wired for 230. I am planing on most of the same things most of you have, although I am not a commercial shop. My next stationary tool will be a large bandsaw 16-18 inches. I am having two plugs put on the new 230 circuit.

[Jim Becker]

You may ultimately need at least three 240v circuits in your shop...one for the DC, one for the compressor and one for tools. (even if you use 120v for the DC and compressor, they really need to be dedicated circuits) This is one of the best reasons to consider putting a sub-panel in the shop...easy adds when you need them. And the cost/effort to run a subpanel isn't all that much more than pulling multiple circuits from the main panel!

[Steven Wilson]

I have no idea if a 30A 230V circuit will be enough. What equipment are you going to buy in the next 10 years? You will probably be better served if you have a 50A or larger sub-panel wired into your shop. Then, as the need arises, you can wire appropriate branch circuits for the specific machines you buy.

[lou sansone]

dear mike


Normally you would not run greater than a 20 amp 120 circuit ( for instance a 30 amp 120 circuit ). You might want to run another 20 amp 120 circuit for all the extra things that you might want to run. The 220 circuit should be fine @ 30 amps for the time. But I could see that you might eventually run a 3 hp unisaw and a 3 hp dust collector at the same time. If that was the case then you would get pretty close to the 30 amps at 220. You could consider running 2 20 amp 220 circuits instead of the 30, or run a 20 and a 30 ( if you plan on a large planer that uses a 5 hp motor or a drum sander you will need a 30 amp circuit ).
regards
lou:)

[Chris Padilla]

All my 240 V circuits are strung with #10 and are protected by 30 A breakers. I did not daisy chain my 240 V/30 A circuits...they are all isolated from each other and have their own breakers.

All my 120 V circuits are protected by 20 A breakers (I also used #10 because that is what I had a lot of but #12 is all you need) and are multi-wired where I could do it.

[Jeff Sudmeier]

Chris outlined the best way to do this. If you are planning for the long haul, you really need to consider about a 100 amp sub panel. This way your needs will be met for years to come.

Jeff

[Mike Holbrook]

I was thinking about using an electrical contractor to: finish wiring a bedroom I just finished and rewire the area that I am making into my shop. The guy was just here, the quote was over $3000. That would put a dent in my tool budget, thats 10 or 15 LN or Veritas planes or a nice new Bandsaw or.....

I am now planing to use my part time help and his electrician friend, between the three of us we will get it done, better for cheaper. I wrap every wire, but I'm not annal or cheap. Hmmm, I guess you guys know better than that you are wood workers right?

The sub pannel idea makes sense to me. I think that is the route I will take. I will leave lights and the already wired outlets on the old panel. I will then put in a subpanel that has probably 3, 20A, 120V circuits (12 gauge wire) to start. One circuit with a few receptacles on it and two circuits with only one receptacle (for large power tools like my 2HP Table Saw). This way I can add 30A, 220V (10 gauge wire) individual circuits as I need them, I have no 220 tools at the moment.

I may go ahead and wire a 220V, 30A individual circuit for the Bandsaw I am planning on, but the location of the subpanel will make it just about as easy to add the circuit later.

[Rob Russell]

If you can run a circuit, running a subpanel is something you can do yourself.


Pull a permit from your town and plan to have it inspected.
Check with the AHJ (Authority Having Jurisdiction, aka the Building Inspector) to see if there are any local amendments to the NEC that you need to be aware of.
You'll need a 4-wire feed for the subpanel and you do NOT bond the neutral and grounding busses in the subpanel.
At the point when you wire the bedroom, you'll most likely need to use Arc Fault breakers for the bedroom circuits.
If you don't have a smoke detector in each bedroom, the AHJ will probably require you to add them (this is building code, not electrical code).


What do you mean by you "wrap every wire"?

Holler if any of the above doesn't make sense.

[Jeff Sudmeier]

One warning with your plan. It might be okay to leave the lights going to the existing box, if you label in the subpanel for the shop that the lights are on breaker number x in the main panel.

HOWEVER, I would NOT have some outlets going to one panel and some to another. If someone comes in to do work on the outlets, they may throw the main breaker in the sub panel to cut the power to all of the outlets in the shop, or so they think. I would think it would be best, and fairly easy to remove the existing outlets from the main panel and run one more wire to the sub.