AIEL Shop Tips WORK SPACE POWER
	For most work spaces, electrical installation will be a consideration, even if only for shop lighting and power tool requirements. This short discussion will lay out a basic electrical distribution for a stage lighting shop. It assumes that you are putting in power for the first time rather than renovating an existing situation. Scale the methods and suggestions to fit your requirements.

Topics

  ELECTRICAL REQUIREMENTS

    Learn what is Safe and Legal: Get an electrical book, or speak to an electrician regarding cable types and sizes for each circuit. In Canada, 20-amp lines should be 12 gauge, while a 30-amp line requires #8, and a 60 amp line, #6 cable. The lower-amperage circuits will terminate in typical U-ground outlets, while the higher-amperage circuits will likely terminate in connectors you'd use to hook up a portable power tap or dimmer rack.

    Study your local the electrical code to be sure what you wish to install is legal, has the proper cable type, and is correctly wired. You may also consider ground-fault circuit interrupter (GFCI) outlets for additional safety. These trip faster and will isolate both the hot and neutral lines from the load when they do.

  ELECTRICAL CONSIDERATIONS

    After fashioning your shop layout, as discussed in the Work Space Design article, you will need to decide how much and what types of power you'll require. The minimum is two separate circuits -- one for lighting and one for tools/testing. Individual work and lighting circuits are recommended so that if you trip the breaker on the work circuit, you won't be in the dark.

This discussion will focus on outlet setups, while
power for lighting will be found in our article on
Area and Task Lighting.

    Shop Electrical Panel: Whether you are bringing in just these two circuits or multiple ones, it is best if you can install a breaker panel right inside the shop. The nature of testing lighting often means that a breaker will eventually be tripped. It's convenient and time saving if that breaker is within, or at least very close to, the shop. This is so you won't have to go far to restore power. In a larger shop where the panel may be some distance away, label the switch and outlet with the panel and breaker numbers so there will be a minimum of delay during the resetting process.

    Circuit Quantity: As a realistic minimum for a medium-sized shop, four to six 15-, or preferably, 20-amp circuits, and one 30- to 60-amp circuit are suggested. The first ones would be for lighting and for bench and work station power. Another might be for a paper-work and computer station, if you've set up one. The high-amperage circuit will be your test outlet for dimmers and high-wattage lights. Separate circuits means no disruption to other circuits should one breaker be tripped.

    Outlet Orientation: Realise that electrical code in Canada specifies the ground connector of each outlet be oriented upward when the outlet is installed vertically. This is especially important when the cover plates are metal. Should the plate ever become loose and drop down to contact the pins of a plug in the outlet, the plate will touch the ground pin of that plug first. In addition, should a plug not be fully inserted into an outlet and a metal object such as a screw driver falls between the outlet and its plug, that driver will touch the ground pin and not short the hot and neutral pins.

    For individual outlets or strips placed in a horizontal position, the neutral side should be up whenever possible. This means that ground connectors would be on the left for a Canadian electrical outlet. So in the same situation as above, a screwdriver would contact the ground and neutral pins, and since ground and neutral are (theoretically) at the same potential, the breaker would not trip. Now, due to leakage current and resistance in the wiring, there may be a small potential difference between the two that might cause a Ground Fault Interrupter Circuit (GFCI) to trip, but in other cases no harm will result.

  BENCH POWER

    Power Strips: After setting up general and specific lighting for your work benches, as discussed in Area and Task Lighting, install an outlet strip along the back of the bench designated for electrical work. Do not put it along the front! Working at the bench and touching a live contact while leaning against a metal electrical strip will result in a severe shock. As well, having the cables for various devices winding their way to the front of the bench contributes to clutter. Remember that the ground connectors should be oriented to be on top.

    A strip along the back assures safety and convenience. It places a receptacle every few centimetres which avoids all cables running to one central outlet box. Mount this strip well up off the bench so that it's accessible should the bench become crowded with tools, meters or cabling while working on a project. Many of our power strips are as far as 20 centimetres above the work surface. (Look for these strips in the AIEL Shop Photo Tour.)

    Switched and Variable Power: Next, set up a switched outlet for simple tests. You may wish to have a variable-voltage outlet, as well. (This cannot be a GFCI type.) Be sure to use an autotransformer for this and not a solid-state dimmer. The transformers can handle much more electrical abuse, and they will give a smoother voltage curve with better resolution. Also, solid-state dimmers may cause interference with some electronics under test. Attach a voltmeter to this circuit for monitoring purposes.

    Location of Switched/Variable Outlets: Test outlets may be at the bench front for access from the floor, but place them off to one side or onto the side of a bench leg. If they must be at the front, recess them enough to prevent contact by personnel during testing procedures. The relevant switch for each outlet should be adjacent to that outlet so there can be no confusion. As well, one may see whether a device is plugged in or not before the switch is used. We like to have each switch be horizontal so that it moves left and right. This way, it points directly to its outlet when it is on.

    Soldering Iron Outlet: Consider a third switched outlet for a soldering iron. These rarely have a pwer switch, so it's a nuisance to plug & unplug it each time. A switched outlet is the answer. Place an indicator light on its box (if not on all electrical boxes), and wire it in series with the switch. This is so you may see at a distance if you have left the iron on. Green is the recommended colour for when this and similar outlets are in their powered states.

    Glue Gun: As above, these rarely have a power switch. It's common to forget it's on, which not only wastes power, but also glue will leak out when it's in a liquid state. Again, a switched outlet promotes safety and frugality. As always, a prominent, illuminated indicator is a must for this type of outlet so at a distance, one can see if the glue gun, soldering iron, or other potentially dangerous device has been left on.

    Other Indicators: For the variable-voltage outlet, use an LED or incandescent light on the output side to indicate general voltage levels. It is also a good idea to have another, different coloured indicator light on the 120-Volt (input) side to let you know that the transformer itself is energized. Green is suggested for 120-volt power, and yellow for the variable side.

A Good Power Setup should Provide Convenience,
and Make for a Safe Testing and Working Environment

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