Questions About Wiring Shop Lights

Discussion in 'Electrical Forum discussion & Blog' started by kailor, Jul 12, 2012.

  1. kailor

    kailor New Member

    Messages:
    22
    Location:
    Huntsville, Alabama
    I want to hang 2-3 8' fluorescent strip lights in my shop located 40' from the house. I want to power the shop lights (on rare occasions) by running an extension cord (on the ground and in good weather only) from the patio to the shop. Ideally, in my mind, I would plug in the extension cord into a receptacle on the patio, walk the female end up to the shop and plug in a male end (wired to the shop lights) and all shop lights would come on at the same time. When I'm done with the lights, I'd just unplug the extension cord, walk it back down to the house, roll it up and put it away.

    1. Is this an acceptable practice?
    2. What fluorescent fixtures are good for hot or cold weather? (The light in my garage came from a Big Box store and works fine regardless of temperature.

    Thanks in advance.
    Keith
  2. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    Is it acceptable? Sure. Is it a great idea? Not really. But go ahead.

    A few caveats: absolutely make sure that the outlet you are plugging into is a GFI. You should also have it fitted with and "in use cover".

    Ensure that the extension cord that you are using is in impeccable condition. No cracks in the jacket or exposed insulation, and especially no exposed wire. Make sure that where you plug in the lights to the extension cord, you are off the ground. Possibly reserve this cord for this use only.

    Fluorescent tend to not like to strike in the cold. They have improved in recent years, but I could not possibly tell you that what you have will strike at say 40 deg F.

    Now I really should be trying to encourage you to do this the legitimate way. How hard is it to dig a trench? You need to go 18" down. That is not that deep. You almost certainly would get by with a 30amp 120/240 service. That is three lengths of 10gauge from a two pole 30a breaker in your main panel out to a sub panel in the shop.

    Run it in plastic conduit. You could use 1/2" but spend a tiny bit more and use 3/4" and the wire will pull itself thru the conduit. To avoid needing to purchase a large fish tape, which for one job is a bit of an investment, pull some pull string (there is a specific product in the electrical dept) thru the conduit as you assemble it.

    Square D has a great 6 space breaker panel that costs next to nothing that I use a lot on gigs like this. You can have a 15a breaker in there for all the lighting, and a 20a breaker for any tools, and still have room for a 240v tool like a welder or air compressor. (A 240v air compressor will deliver LOTS of air!)

    You need to drive a ground rod near the new sub panel, and you need to ensure that any neutrals in your new sub only connect to the neutral bar in the sub, with no connection to the grounds or the case of the sub panel, and that all the grounds and metal components be bonded together and grounded to the ground rod. (You do not attempt to link the grounds in the shed to the ground in the main panel).

    If there is any plumbing in the building, it should be bonded to the ground as well to ensure that it is at the same potential as the ground rod and the grounds running in the shed.

    If the materials all come to $250 I'd be a monkey's uncle.
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,255
    Location:
    Cave Creek, Arizona
    I would wire in a switch at the shop so you do not plug and unplug under a load. SInce he is only asking about lighting he does NOT need a 30 amp 240 circuit. Nor does he need a branch circuit subpanel.
  4. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,565
    Location:
    North Carolina
    This is true and it will work for a period of time before failure starts. This is what Homeowner was addressing. Time is one of the best story tellers known to mankind.
    Experience is gained with time and the more time one spends on earth the more experience he gains. In the experience of most any electrician one has the knowledge that most will start with lights for a short period of time and the need for a receptacle comes into play so this is added with the same old supply.

    As time progresses more receptacles are installed and then one day there is a V8 engine hanging on a walnut tree limb and all sorts of lights so work can be done at midnight.

    Come winter and there is a skinning rack built and then two deep freezers needed for all the meat. Spending all this time out here rebuilding the 350 and skinning out all those animals is killing me running back and forth to replenish my beer supply. Now I need refrigerator for beer for me and all my buddies that have started hanging around.

    Now I need a place for them to relieve their self as the wife has started looking out the window for a glimpse at my buddy’s manhood. Wait this is a subject for the plumbing forum.

    I understand where Homeowner is coming from and agree with advice for a long time solution to a problem that will most definitely occur. Maybe I exaggerated just a little but I think everyone has the idea that a permanent installed circuit is far better than the cord idea. I think that we will all agree that the gathering of the cord after each use would be the exception to reality.

    The only difference is I will recommend the installation of four conductors, 2 hot, 1 neutral, and an equipment grounding conductor. This will meet the newest version of the NEC or ICC codes. If three wires are installed the panel in the building will need to be installed just as any other main panel. There can be no other electrical path between the two buildings such as phone, cable, metal water lines, or any other electrical path. Should such a path be installed then there must be four conductors and neutral isolation.
  5. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    Relying on an extension cord is a dubious practice.

    And my suggestion is tiny money. Digging the rotten trench is the worst part. Hire a kid for that.
  6. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,565
    Location:
    North Carolina
    Sometimes in life some of the strangest things happen.
    I have just returned home from a situation similar to this post. My neighbor bought a 16 x 12 foot building two years ago and installed a 20 amp 120 volt circuit to it to power lights and two receptacles that were installed when he purchased it.

    Last spring he purchased a new chest type freezer that he installed in that building. This morning he called me to see if I could come over as he had a service tech there checking out the freezer and the service man said it was a problem with the incoming power.

    When I get there I find a through wall AC unit to keep the heat down for the freezer as well as a wall clock and an alarm system installed all on this one 20 amp circuit.

    Anyone want to guess what my advice was? I will give you a hint, it was the same advice I gave him when he ask about how to install the 20 amp circuit two years ago.

    For the next few days his meat will not see any AC nor will it be protected by an alarm. No lights and the battery charger to keep the lawn mower battery charged is unplugged.
  7. Homeownerinburb

    Homeownerinburb New Member

    Messages:
    525
    Location:
    Los Angeles, CA USA
    And how much would it have cost your neighbor to have had a contractor over to dig a trench, then to do the rest of the work himself?

    Some 3/4" conduit for power, some 1/2" conduit for communication.
  8. jwelectric

    jwelectric Electrical Contractor/Instructor

    Messages:
    2,565
    Location:
    North Carolina
    Went over this morning before church to look at his work before tomorrow’s inspection.

    I like to have fallen out until he told me he is planning on adding to the building in a couple of weeks and will need more power.

    He has buried two 1 ½ inch PVC lines, one for the 100 amp panel he has mounted to the side of the building and is supplying it with an 80 amp circuit on #2 USE the other for future needs.

    He also ran two ¾ inch ABS pipes for I don’t know but suppose it is for water and whatever, all this as deep as the trencher would reach ~ 36 inches.

    His work looks real good and it will pass inspection with one of the PVC in the panel and the other in a 6x6x6 PVC box. Each ABS pipe is capped off about 18 inches above ground. Two rods about 10 feet apart down about 12 inches blow the ground. GFCI if a weather box just under the panel looks real good. Two GFCI breakers in the panel for the circuits inside the building.

    He said that he should have done this to start with and maybe he wouldn’t have lost $350 worth of meat in the freezer. I understand that when he first moved there he had just bought that trailer and the expense of moving but like he said, pay the fiddler today or tomorrow but at any rate if you are going to dance someone is going to pay the fiddler.
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