Planning workshop circuits - advice needed...

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  #1  
Old 04-12-05, 10:49 AM
boppa7
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Planning workshop circuits - advice needed...

I am adding some new circuits to my workshop as I currently only have a single 15amp circuit for all tools, lights, etc.

Given that the lights are all on the existing 15 amp circuit I figure that all I need to add is some receptacles for tools. My current plan is this...

Circuits 1 and 2 (one on each side of the shop) each being 15 amp and having 3 standard receptacles

Circuits 3, 4, 5 and 6 (3 and 4 on one side with 5 and 6 on the other) each being 20 amp ending at 2 split-duplex receptacles

This will give me 6 receptacles on the two 15 amp circuits for small power tools and 2 receptacles on the four 20 amp circuits for my table saw, dust collector, compressor, etc.

Comments?
 
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  #2  
Old 04-12-05, 11:22 AM
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Far too many circuits if you are going to be using this workshop by yourself. Figure out how many tools that you might simulataneously use, and install that many circuits (plus one for lighting). Add an extra circuit if you need an airconditioner, heater, refrigerator or freezer. If you do any welding, make a special circuit for that. Make all the circuits 20 amps. There's no need to make any of them 15 amps.
 
  #3  
Old 04-12-05, 01:18 PM
boppa7
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John,

You got me thinkin...

Yeah - I may just be overdoing it on the circuits. However, I have installed a new 8/16 sub-panel in the garage to accomidate the installation (using 6, leaving 10 empty). Was your comment related to the use (waste) of too much panel space or was it to do with something else?

Thanks,
Jason
 
  #4  
Old 04-12-05, 02:21 PM
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There's nothing wrong with that many circuits. But each circuit adds to the total cost and effort, but not really very much. I use full-size breakers (easier to flip on and off) and if you do, you'll use up that panel space faster. You may later want other stuff such as a welder, heater, air conditioner, freezer, kiln, etc. and then you might need that space.

But by all means, go ahead with your original plan if you prefer. You can't really have too much power.
 
  #5  
Old 04-12-05, 04:04 PM
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I noticed that

you didn't mention any 220V outlets...but you did mention an air compressor, and a dust collector. Some table saws are also 220V.

Quite a few of your higher horsepower tools will be 220V. Did you already own the tools or have some in mind?

Just something to think about!! You could always add them in later, if needed.

Hope this helps!
 
  #6  
Old 04-12-05, 04:14 PM
boppa7
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Desy2820,

Very good point... Here is my plan...

Each wall will have a 20 amp split duplex receptacle (two hots). If at some future time I acquire a 220v compressor or saw I will simply replace the split duplex receptacle with a single 220v receptacle.

At the moment I do have a table saw, compressor, mitre saw, shopvac and drill press that are all rated for 110v. Only 200v purchase that I am considering is a new compressor and the one I have my eye on can run either 110v or 220v.

Jason
 
  #7  
Old 04-12-05, 06:08 PM
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Originally Posted by boppa7
Each wall will have a 20 amp split duplex receptacle (two hots). If at some future time I acquire a 220v compressor or saw I will simply replace the split duplex receptacle with a single 220v receptacle.

I get the impression from this statement that you are planning to feed these split duplex recepticles with multiwire circuits. It also sounds like you plan to use "twin" breakers, since 6 circuits leaves 10 spaces on the 8/16 panel.

If both those things are true, keep in mind that the two hot legs for each multiwire circuit must be on opposite phases in the panel, and that the two halves of a twin breaker cannot provide both phases (though I believe there are some manufacturers who's panels provide for that). Also, if a duplex receptical is split and fed by a multiwire circuit, you need the two breakers to be tied together, so that if one trips, the other does as well (and so the next guy who thinks he's killed power doesn't kill himself because he only shut off power to the half of the receptical he tested). Put all this together, and you may be wanting quad breakers with the inside and outside pairs tied together (my old Murray panel has a quad breaker...providing juice to two 30AMP, 220V circuits). Here's a picture of a quad breaker made by Siemens:



Note that one 220V circuit comes from the middle of the quad, and the other from the outside.
 
  #8  
Old 04-12-05, 07:10 PM
boppa7
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chirkware,

Great point and I already considered this. I am using cutler hammer breakers that are quad pole with 15amp on the outside with 20s in the middle connected by a tie-bar.

From what I have read, in addition to the concern about only shutting down half of the receptacle, the opposite phase needs to be respected because there is only a single neutral wire for both hot wires.
 
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