OLD HOUSE - Wiring and Outlets?

HI there. Hope you guys can help. I bought an old house. 212 years old to be exact. It's got 28 inch thick stone walls and the interior finish on the stone wall is Horse hair plaster applied directly to the stone. The first room that I've chosen to redo is on the second floor and has 3 exterior walls (stone) and the interior wall that makes the fourth side of the room is double plank with wood lath and plaster over it (no real void space in the wall).

I plan to run new circuits up to the room from the box in the basement by creating a utility "raceway" in the corner of the room that now has a built in closet.(first floor room below also has a closet in the same place) This way all wires would be hidden from view at the back of the closet.

This raceway will continue up into the attic so that light fixtures on the second floor can be fed from above, and the attic can later be finished into living space.

All wires in the raceway will be in closed in Conduit, and removable panels in the rear of the closets will allow access to that conduit if necessary in the future. Here are my questions....

1.) how many wiring runs can I put in one conduit run? I plan to have 3 circuits for the room- one for light fixture in the room and in the adjacent hallway and 2 for the receptacles in the room. I also plan to run at least three circuits up to the attic for future use. Can I use one appropriately sized conduit for the room and another for the attic or must I have a seperate conduit run for each planned circuit?

2.) Outlet placement within the room? The room is 13 x 16 and has 2 receptacles on each wall mounted into the baseboards. I hoped to run the circuit for the receptacles using either sheilded cable or cable in conduit behind the base boards and utilize the exsiting holes in the baseboard to house the new receptacles. Can I place receptacles in the baseboard for the purposes of maintaining the historical integrity of this house? Or is the code inflexible on their placement? All prior electrical work that I've been involved in used the length of hammer method to place them in the wall about 15" off the floor.

Thanks for any input that you can offer. I do have a few books on wiring per the 1999 NEC, but I couldn't find any information that would help me since this is a historic restoration.

 

1) How many wires you can put in conduit dependes on the size of the conduit, the type of conduit, the size of the wire, and the type of wire. There are many pages in the NEC that cover this. We'd be happy to look up any specific entry for you if you provide those four pieces of information. There are two considerations: how many will fit safely without damaging the insulation, and how large the wires must be for the amperage to safely dissipate heat. These two considerations must be evaluated separately.

2) Yes, there is no problem putting receptacles in baseboards (assuming "baseboards" means wooden trim pieces). There is no requirement that they be 15" high.

 

Unless a local requiremant for conduit exists, or the house is to tall for NM, conduit/emt is a pain in the... Even AC (BX) is easier to run. The only advantage to conduit is that if you put oversized conduit in, you can come back and upgrade the wiring. If you do not oversize, the conduit is full at installation, and you cannot add anything. I would run NM (or BX if required) and add some extra runs right from the start. I just remodeled a kitchen that is above my panel, so there are three 14/3, three 12/3, two cat 5, and two 5 wire thermostat runs installed from basement to attic through the kitchen and one bedroom on second floor. I probably should have put in some coax and smurf tube while the walls where open but had to draw the line somewhere.

 

Thanks for the responses guys.


John:

As for the multiple lines in one conduit question, I haven't calculated the loads on the line but I'm leaning to 12 guage since it will be almost 100 feet from the box to the last receptacle on the circuit and I'm concerned about the resistance of such a long run causing a problem with 14 ga wire.(and who knows what my teenage kids are going to want to plug into the wall 14 years from now) As for type, I was going to use the stuff that Lowes or HD sells with the white vinyl coating. (or do you advise against this ?) For conduit I was going to use the rigid Plastic stuff or maybe even metal since I have a lot of room to work and there won't be any bends involved. I figured that 1 inch would allow for (2) 12 ga wires.

In the space behind the baseboards I was thinking about using the metal wrapped wire. (I don't know what you call it) I haven't gotten back there yet to see what kind of room I'll have. If there's enough I might just use conduit .

Brickeeye:

What is NM and BX?

Thank for the suggestion on placing the extra runs now. That was part of the reason that I wanted to use some sort of conduuit. I figured that at least I'd have a chance of fishing another wire through existing conduit if I found a need for it later.

 

NM is non-metallic cable. It's that "stuff that Lowes or HD sells with the white vinyl coating."

If you use conduit, I recommend against the NM, in favor of THHN (go to Home Depot and ask to look at some THHN). But like brickeyee, I'm not sure why you're considering all the trouble of conduit. In most areas, you can simply use NM without the conduit.

Don't start this project until you read three more books on home wiring.

 

Thanks.

Again, the use of conduit is to make it easier to run another line later if I need to. Just drop the fish down from the top, attach the new line, pull it up through the conduit and presto, Nice, neat and done. No snarl of wires to look at either.

As for reading the books, I have at least 4 more to go before I put the pliers to the wire. I just didn't want to be haunted by these questions for the next month before I start.

Thanks again for providing this great resource!

 

Get a copy of the NEC (or another code if your area is on another). The conduit fill rules are in Appendix C of the NEC. The number of conductors varies with the type of conduit (ridgid, EMT, non-metallic) and wire gage. Pulling in already filled conduits can be a real pain. Going up one wire gauge at 100 feet will not hurt anything, but I do not have a wire table handy to see what the drop really is. If you do calculate it, remember to use the resistance of 200 feet of wire. The current has to go both ways. (out and back)

 

I know that in most parts of the world a 212 yr old house still probably has wet paint on it...
But here in the States, thats Old! Double check with your locality as to any special rules for a house of that age..
Historical or otherwise...

Curtis

 

I now modify my earlier recommendation. I see no reason to mess with THHN for this simple use. Just buy the 12/2 NM-B cable. That way you won't need a big splice box where the wires enter and leave the conduit.

Put in 1.5" schedule 40 PVC conduit and pull 12/2 NM-B cable and a cord (for future pulling) through it. I recommend 1.5" because it is enough for up to four 12/2 cables, giving you some room for the future. And four such cables is the most you can put together without ampacity derating.

You not need provide access to the conduit after you put it in (except the two ends for pulling future wire).

 

If you pull in NM use 12-3. It is rounder and easier to pull, and by running multiwire circuits each cable run can support two circuits.