Crawlspace wiring

[HerHusband]

Frank,

Doug described the idea fairly well, but here's how I would do it:

Use 12/3 w/ground cable. The black hot wire just passes through each light box, on it's way to the switch. The switch then goes between the black hot wire and the red "switched" line. Here's some bad ASCII art:

Black --------------------------------------------+ Source: | White --------+--------+--------+-------+ | | | | | Switch Light Light Light Light | | | | | | Red -+--------+--------+-------+---------+

This would give you a switched red lead and an always hot black lead in every box, allowing you to add outlets at each box if you wish.

Be sure to protect the crawlspace circuit with a GFCI circuit breaker.

I had planned on a similar wiring scheme in my own house, but in the end I found it easier to just wire an outlet in the crawlspace. I can easily plug in a worklight as I enter the crawlspace (just leave it in the crawlspace until your job is complete), and it lets me plug in power tools when needed. Once the job is finished, you probably won't be venturing into the crawlspace very often.

Anthony

[Wayne Whitney]

This is an excellent answer. Just to clarify, you only need 12/2 between the source and the first load, since up until the first load, there is no need for a distinction between "hot" and "switched hot". The other poster's suggestion about adding an outlet near the crawl space entrance is a good one.

Note that if you did want to add an outlet near the entrance, and want to use a GFCI outlet to also protect the lighting loads, you would need to run 12/2 straight to the outlet, and a separate 12/2 run back to the lights. This is because the neutrals on the GFCI protected loads need to be connected downstream of the GFCI device.

Cheers, Wayne

[HerHusband]

Wayne,

True, but it's easier to buy a single roll of 12/3 and cap off the extra wire, than it is to buy a roll of 12/2 and 12/3 and end up with a bunch of extra cable left over.

Also, by running the separate third wire to every box, you could easily relocate the switch anywhere along the line.

Oh, and there's no reason you couldn't use 14 gauge wire (15 amp breaker) for this simple lighting circuit. I just prefer 12 gauge (20 amp breaker) for exterior circuits (never know what you'll be plugging in out there).

You could always add a GFCI outlet at the start of the run before it moves on to the lights and switch. Although, it would be awkward to reset if tripped and may be a code violation because of that?

I would personally opt for a GFCI breaker back in the panel.

Your approach would work well too, and may end up being cheaper than a GFCI breaker, even though it uses more cable. Certainly, if you already have a supply of 12/2 cable on hand, it makes sense to use your approach.

In my house, I put the crawlspace and exterior lights/outlets on a single "exterior" GFCI circuit.

Anthony

[HerHusband]

Doug,

I know this is code acceptable, but I don't like doing it. To me white is neutral and should always be identified as that. You're supposed to identify a white wire as a black wire when used in a switched arrangement like this. I prefer to run the three wires all the way to the switch, and cap off the neutral line. This also allows me to add an outlet at the switch at a later date if I need to (assuming the circuit is already GFCI protected).

Running the 12/3 for the entire circuit also simplifies buying cable at the store. One roll for everything...

Anthony

[vinegarhill]

This is probably a stupid question, but the Corps always told me the only stupid one is the one not asked. So, here it is. I have an old house and have been working on it - rewiring, plumbing, masonry, construction, etc.- for the past few years, new additions and updates, as time permits. No problem. Electrically, I'm up to code, but am nervous about electricity, which is why I double and triple check everything. I have a nice crawl space under the house, clean and dry, but it only has one entrance, and every time I go under to do some work, I have to drag a work lamp with me. I want to string four permanent lights connected to an on/off switch by the entrance. The power has to come from the far back corner of the house, then the four lights, and then the switch. But I cannot find any diagrams or schematics that show me how to wire in this configuration. I know there has to be some type of switch loop, but I can't figure out how to wire the lights; in series or parallel, or series-parallel. If anyone can help, I'd appreciate it. Thanks, Frank

[Doug Miller]

Conceptually, the simplest way to wire this is to run a cable from the service panel directly to the switch, another cable from the switch to the first light, another cable from the first light to the second light, and so on. In the switch box, connect the two white wires together, and the two black wires to the two terminals of the switch. At each light fixture except the last, connect short black and white wires ("pigtails") to the hot and neutral sides of the fixture respectively; then connect the whites together, and connect the blacks together. At the last light fixture, just connect the black and white wires directly to the fixture.

-- Regards, Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt. And who wants to leave buttprints in the sands of time?

[Goedjn]

If you do that, then you have to use the white wire in the 12/2 for the supply or switched hot, which means you have no nuetral at the switch, which in turn means you can't have a lamp or plug there.

[Doug Miller]

Right, but the last leg between the fourth light and the switch should be

2-conductor cable. Connect that cable's black to black, and its white to red, at the light; then connect the switch between black and white.

Yep.

-- Regards, Doug Miller (alphageek at milmac dot com)

Nobody ever left footprints in the sands of time by sitting on his butt. And who wants to leave buttprints in the sands of time?

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Use CCFL or heavy duty light bulbs so that they won't all be burned out due to floor vibration next time you go down there.