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Braphael
10-23-2012, 04:06 PM
I am quoting a project for a house on the ocean where the owner wants the transformers mounted in a mechanical room on the second floor in order to be above the flood line. I realize I will need to spec transformers rated for indoor use. My question is - what is the proper way to wire thes through the wall down to the ground floor and out and into the ground and ...?

S&MLL
10-23-2012, 04:51 PM
I would recommend using speaker wire for the indoor wiring. Then switch to cat-5 Ethernet wire once you go outside the home.

Just keep watts under 500 on the speaker and 400 on the cat-5 and you should be fine

Braphael
10-23-2012, 05:20 PM
And your serious comment would be?

GreenI.A.
10-23-2012, 06:05 PM
Will they let you mount conduit onto the outside wall if you can do so conspicuously? PVC conduit can be painted if you scuff it up first.

We regularly mount transformers and irrigation controllers inside finished garages. To run the wires through the walls we simply drill through the wall and slide in a piece of PVC conduit, usually 1.5" or 2" depending on the number of wires. Be sure to insulate around the pipe if it is an insulated wall. We then use a junction box on the ends of the conduit on each side of the wall. That gives a nice finished look that covers the pipe in the wall. On the outside we then run a piece of conduit from the junction box to just below grade. We then use silicone to plug the end of the conduit underground so that no creepy crawlers make their way up into the conduit. On the inside you can have the wires come out of the inside junction box or for a more finished look, we'll run conduit from the junction box to the transformer.

We paint the outdoor PVC conduit, junction box, and fittings/mounts to match the house. Last thing we will do is put a piece of insulation in both the inside and outside j-boxes to eliminate heat and cool transfer.

Braphael
10-23-2012, 06:38 PM
All the utilities come into the side of the house very low and run upstairs in conduit. The house is a new build, so running conduit upstairs is not a big deal. My concern is about the type of wire allowed. Do I need to provide a junction box in the ground outside and transition to romex in conduit to meet the codes for interior wiring, or is low voltage wiring allowable as long as it is in conduit. I can't find a good answer to this in the NEC codebook. This is a very high end builder with very high end clients, and my first shot at doing work for him.

steveparrott
10-23-2012, 07:16 PM
All the utilities come into the side of the house very low and run upstairs in conduit. The house is a new build, so running conduit upstairs is not a big deal. My concern is about the type of wire allowed. Do I need to provide a junction box in the ground outside and transition to romex in conduit to meet the codes for interior wiring, or is low voltage wiring allowable as long as it is in conduit. I can't find a good answer to this in the NEC codebook. This is a very high end builder with very high end clients, and my first shot at doing work for him.

Bill I suggest you post this question on the Mike Holt Low Voltage forum (http://forums.mikeholt.com/forumdisplay.php?f=64) - there are some serious code wonks there.

Steve Atkinson
10-23-2012, 07:49 PM
Have you inquired at the local city/county building department? The building/electrical inspectors are your best source of how to. Will save you a lot of $$ and headaches down the road. They surely will be able to provide the best and safest method.

Braphael
10-23-2012, 09:05 PM
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Braphael
10-23-2012, 09:09 PM
Thanks Everyone. I made the mistake of asking a group of electricians at the supply house and it was amazing now many different answers I got. I think I will go to the county an ask the electrical inspectors. I'll see what they say.
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S&MLL
10-23-2012, 10:21 PM
You need to go from low voltage lighting wire to romex or suitable indoor rated wire before you enter the home. Most of the time done via a lb. Some will enforce fire caulk inside the lb at the transition to romex. From there on out wire as you would prewire romex in a home
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Braphael
10-23-2012, 11:34 PM
Would it be better to transition to THHN or romex?

S&MLL
10-23-2012, 11:40 PM
Why sleeve and pull thhn when you can just run romex. If the walls haven't been rocked yet why bother going crazy. Plus you cant turn more then 180 degrees. Sounds like you will have a bunch of bends and pulling might not be an option.

Braphael
10-24-2012, 12:02 AM
Good point! Thanks.