workshop electrical outlets

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  #1  
Old 11-28-05, 12:23 PM
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workshop electrical outlets

I think I read somewhere that when installing outlets in a residence that the wall outlets should be spaced no more than 6 feet apart. What is the code for a workshop? I'm basically installing outlets to run machine tools only, i.e. joiner, band saw, dust collector, mitre saw, etc. Any help would be greatly appreciated. TKS!!!
 
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  #2  
Old 11-28-05, 12:34 PM
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The code for the living portions of a residence is that no portion of the wall should be more than 6 feet from a receptacle. This way you could place a lamp anywhere without an extension cord.

In a workshop, you generally want far more than this minimum; you want outlets placed conveniently for each of the tools that you plan to use, plus several above each workbench. There isn't specific code for how many outlets belong where, and you will instead be placing outlets based upon your design preferences. There are code requirements for the size of circuits going to various tools.

You want to use separate circuits so that large tools that are fastened in place have their own circuit, and so that any tools that you expect to operate at the same time will be on different circuits.

You want to place your lights on a separate circuit, so that when you screw up and overload the saw and blow the breaker, the lights don't also go out.

-Jon
 
  #3  
Old 11-28-05, 01:55 PM
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Jon....thanks for the info. To give you a bigger picture, I'm planning on running 4 - 5 outlets per circuit (30A w/ 10G wire). I'll have 3 30A circuits for the tools. Plus, and I'm not sure of the amperage, I'll have my florescent lights on a separate 15A circuit...leaving a 15A circuit for future plans. My other lines will be 2 60A circuits for 2 220V outlets - 1 for the dust collector and 1 for the space heater.

As far as each of the 30A circuits go, the highest amp tool is around 24A. The total of the amps for the tools plugged into each of them may or may not be more than 30A, for none of them will be run at the same time.

Confused yet? Hope I explained what my plan will be.
 
  #4  
Old 11-28-05, 02:07 PM
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You have some reading to do before you go any further. I'd suggest that you buy or borrow _several_ books on electrical wiring and bone up on the necessary background.

You can't connect ordinary receptacles to a 30A circuit. The 24A tool should be on a dedicated circuit, as should the dust collector. The space heater will require its own circuit, sized based upon the rating of the heater, most likely _not_ a 60A circuit. I rather doubt that you need 60A for the dust collector; do you really have a 10-15hp dust collector?

If you are installing such large tools, then before you do anything else you need to do a demand calculation, and figure out what size service is required!

-Jon
 
  #5  
Old 11-28-05, 02:37 PM
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Will definately be doing more research for this project. I looked back at the tools we have and their amperage. The largest being the dust collector at 24A. I don't know (yet) about the HP tho. This will be on its own circuit. The space heater is 10A and will also be on its own circuit.

The 3 30A circuits are broken down by A.) 5 tools - 12.5A / 15A / 2.5A / 15A / 10A; B.) 1.8A / 2.5A / 5A / 2.5A / 8.8A; and C.) 7.5A / 13A / 8.4A. I WILL make sure that none of the tools on the same circuit will run at the same time.

The 60A for each of the dust collector and space heater may be overkill, but better go higher than lower right?

Also, what do you mean by 'ordinary recepticles'? I'll use whatever is correct for a 30A circuit. I DO also plan on beginning each line with a GFCI outlet.

Any suggestions on how/what to do a demand calculation?

Thanks!

Mike
 
  #6  
Old 11-28-05, 02:56 PM
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You can only place 30A receptacles on a 30A circuit. 30A receptacles are _not compatible_ with ordinary receptacles. So you wouldn't be able to plug your standard 120V tools in to these receptacles. If you put 20A receptacles on a 30A circuit, you will have a code violation and a significant safety hazard.

For 'general receptacle outlets' you should use _20A_ breakers, and either 15A or 20A receptacles. GFCI receptacles are a good idea, and required by code for certain locations in your house (often required in workshops, but not always).

For _specific_ tools that require higher currents, you will use 30A, 40A, 50A or even higher amp circuits, and you will use either special receptacles or you will 'hard wire'. The correct circuit size will depend on the tool, and the installation instruction should tell you what sort of circuit is required.

Bigger is _not_ necessarily better. The rating of a circuit tells you (approximately) how much power the circuit can deliver before the circuit breaker trips. Equipment is designed with this breaker rating in mind; using a circuit with a higher rating could present a situation where the device overloads and fails, but where the circuit breaker does not trip. Connecting a device designed to be used on a 20A breaker to a circuit with a 30A breaker is as wrong as connecting a 12ga wire to a 30A breaker.

Bigger _might_ be better if you correctly provide protection. For example, running a 100A subpanel to a workshop is 'better' than a 60A subpanel...but the final breakers will all be sized correctly for the branch circuits served. But even here there are pitfalls. For example, running 10ga wire to a receptacle (for lower voltage drop) means that you need to use receptacles with 10ga terminations, and you need to use larger device boxes and enclosures, otherwise you introduce 'box fill' problems, and could over-all reduce safety.

A good book on wiring will describe just how to do a demand calculation. Also, if you search these forums, you will see many questions on the subject.

In any case, do the reading, you are on the right track by asking the questions!

-Jon
 
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