flourescent lighting


  #1  
Old 01-22-06, 02:22 AM
obxroadking
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flourescent lighting

Hi, I have four 48 inch single lamp fixtures that are supposed to be hardwired. I want to install them over my work bench. I was wondering if I could hook them all together with one plug and put them in a standard wall outlet. If so, what gage wire would I need to use? Thanks in advance!
 
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Old 01-22-06, 12:52 PM
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Hardwire all four units together with 12-2 NM-B, using proper strain reliefs. On the one closest to the point where you want to plug it in use 12-2 wg SO with a plug on the end you want to plug it in with. Personally, I would want to wire it through a switch to keep from having to plug it in every time I wanted light.
 
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Old 01-22-06, 01:38 PM
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Assuming a magnetic ballest and an F40T12, the worst case, you are looking at about half an AMP each. #12 is a bit of overkill.

If you still want to use a single cord to plug in all the lights, a #18 3 wire cable is good for 14 AMPs as long as the insulation is rated for 90 deg C. - There are better ways to do this though

I'd think about wiring in a wall switch that operates two receptacles, each mounted halfway between two lights, and installing a cord rated for use with the temp rating indicated on the ballest on each light (90 deg C). In the scheme of things installing the cords and receptacles isn't that much more work. You will find as time goes on that it's nice to have the option of having some of the lights on while you have to work on another one - unplugged of course.

If you wire in receptacles, #14 is fine. The pigtail for the light fixture would need to be only #18 or #16 cord - remember, rated for use on the fixture.

UNK
 
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Old 01-22-06, 01:56 PM
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You can't install smaller wire than the circuit calls for. If it is protected by a 20 amp breaker, it will have to be 12 gauge wire.
 
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Old 01-22-06, 02:43 PM
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if there supposed to be hardwired like you say use emt with thhn and pipe around to each fixture the power source and a switch.
 
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Old 01-23-06, 07:23 AM
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If you decide to hardwire in the lights with NM-B or some kind of conduit, the wire must be at least the minimum size required for the breaker on the circuit.

Once you to decide to plug the lights in, the rules change. Although some lights are designed to be plugged in and not hard wired, the opposite is seldom true where the light is REQUIRED to be hard wired and as long as the cord is rated for 90 deg C there is usually no issue wiring the fixture with a cord. In this case the cord need only be large enough for the connected load. The NEC covers this in article 400, and specifically allows the use of flexible cords and cables for use with light fixtures.

If you are using fixture wire the rules change again. The article that covers this type of wiring is 402, and the table that tells what size fixture wire may be used is 240.5 In this case smaller wire than what is normaly on a circuit may be used (for example, #18 may be directly wired to a 20 AMP circuit if the length is 50 ft. or less) to tap the circuit conductors and supply the fixture. Other rules also apply here. BUT......

Using a flexible cable (cord) is code recognised for the use you propose.

UNK
 
 

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