I am re-wirng basement and wonder what type of wire, NM or BX I should and/or have to use. Part of existing wiring in my 50+ year old home done by NM cable (grounded) and part in basement is done with BX cable.

 

We need more information. Is this wiring to be done in new framed walls, on cinder block, etc...

 

The basement is unfinished yet. Wires will be fixed to frame and joists.

 

Unless local codes prohibit, I would definitely say NM cable. It is easier to work with and is much cheaper. The BX may have been run in your basement because of local codes, or simply because it is exposed and is visually more appealing. If the cables are strapped on cinder block walls then NM could not have been used in such an application although conduit would have been preferred over BX. Are the outside walls of your basement "framed"? What are you planning on doing with your ceiling? Are you framing and sheetrocking the entire basement?Once again, if you can be a little more descriptive in what you have now and what you plan on doing, there may be some other considerations that need to be addressed.

 

Outside walls are framed. There will be several rooms in the basement (workshop, library, exercise room). There may be a half-bathroom too. I am going to insulate the basement with R-13 batt insulation. The workshop walls will likely be paneled, other rooms will be finished with 1/2" dry wall. I will probably install auqustic ceiling tile. There is 50 A sub-panel in the workshop and workshop lights and receptacles are powered from the sub-panel. All other rooms and corridors will have recessed lights controlled by dimmed switches. I currently have one wire used to power a couple of existing receptacles. The only light in basement sits on the same circuit as other house rooms. This only wire is NM wire going to first receptacle then starts BX wire to the next receptacle. Both wires are 20 A wires. I want to use existing wire for all basement lights and run new 20 A wire for all basement receptacles. So I wonder what type of wire (NM or BX) I should use.

 

NM

 

Unless prohibited by local code, definitely NM. I don't know why local codes would preclude you from using NM in a finished basement. Staple wiring to the center of the studs and use nail plates where you have to drill through with less than 1 1/4" of wood to surface of stud. Staple your wires above the drop ceiling to the bottom of the floor joists.

Like I said, MC cable (formerly BX) is much more expensive and harder to work with. You would have to use metal boxes with MC connectors and would have to ground the boxes as well which is very time consuming. With NM (romex), you unroll the wire as you go (don't let it "barber pole" or you will have a tough time pulling it through holes) and use plastic nail-on boxes which are a breeze. Pay the extra money and use the deeper 22 cubic inch boxes everywhere instead of just where you need them due to box fill considerations. You don't have to "bond" the boxes. You will need at least 1000' (4 rolls) of wire for your job, not including 3-wire cable for your 3-way switches and the cost and especially labor will add up quicker than you might think. I would use 14-2 and 14-3 for the lighting (on a 15 amp breaker) because it is even easier to work with than 12 guage plus you don't get into as many box fill problems. Lighting is a controlled load so you don't need the 20 amp circuits.

Of course, I'm speaking from how it would be done where I live, and there may be some other way of doing things where you live.