Will my voltage drop?

[RayV]

I am in the thinking it out stage of re-wiring my house. I know my bank balance will drop with the current price of copper but will my voltage? The house is two-story standard construction with an unfinished basement and attic access, the breaker box is in the basement. My goal is disturb as little drywall as possible. The furthest run will be to an upstairs bedroom.

Rough calculations give me:

50' to the other side of house 30' to first outlet (up to attic and drop to outlet) 25' to next outlet (up to attic, over a few feet, and drop to next outlet) 25' to next outlet (up to attic, over a few feet, and drop to next outlet) 25' to next outlet (up to attic, over a few feet, and drop to next outlet) 25' to next outlet (up to attic, over a few feet, and drop to next outlet) 25' to next outlet (up to attic, over a few feet, and drop to next outlet - 6 outlets in room) 205' total estimated feet of wire.

Will voltage drop be a problem using 14/2 wire on a bedroom circuit

205' feet from the panel?

A friend who will be helping me suggested I put a sub panel on the second floor to cut back on the amount of wire run. While this may be true I'm not that thrilled with this idea. Main reason being I assume the inspector will want the sub panel in an accessable area (not a closet) that will require a 'decorative' picture. Any thoughts on this?

[gfretwell]

That may be the best option. You can then take advantage of diversity. You won't have every circuit on the sub panel running at any significant fraction of 100%. If there are no fixed in place loads you are probably only looking at 3va per square foot as youir feeder design load, even though you will have breakers in there that add up to a lot more. You can support 2400 square feet of general lighting load on a 2 pole 30a feeder/breaker. When you finally do plug in that hair dryer it will be on a 10ga wire most of the way, not a 12 or 14. If you really think you are going to load this area up you could go to a 8ga/40a sub/feeder but that may be overkill.

[George E. Cawthon]

I wouldn't be so sure you can't put the subpanel in a closet. I have a subpanel in my furnace room which is basically a closet about 3 feet square. Ask an inspector. Even if it is not permitted where you live, there are places where you can put it and simply cover it with a painting, a mirror, or use your imagination.

[mm]

How about going across and up to the attic with 12 gauge? Or 10, what do I know?

And then using a junction box or two and from there, directly to each outlet. None of this down and up and down and up etc. etc.

That would make every run 90 to 130 feet. You could definitely use 12 gauge from the junction box to each outlet, unless something unusual is used at that outlet.

How many wires can properly go in a wire nut? If four, you could spin off two outlets on the first one, and two at the next, and two or three at the next. If only 3, is there nothing that can be used, that is short of a subpanel (with circuit breakers, I assume that means, that can trip and have to be accessible), that can just be installed in the attic and left there, like a bigger than average junction box?

IANAE. I am not an electrician.

more below \\

Unless you go naked to work every day, a closet is accessible. Although I have no idea if that makes accessable enough for the inspector. Maybe you could put a combination on the subpanel, so that burglars think it is your safe. If nosy guests looked behind the painting, they would be impressed that you had a safe!

Then you could put your safe in the basement looking like a sub-panel.

[Goedjn]

The allowable combinations are written on the box, usually.

[Toller]

Well, it all depends on what the circuit is. Most circuits only have a few amps on them, so voltage drop is not a serious issue.

Somebody suggested 12/3. That will certainly help if you do have more than a few amps. Without looking it up, it is maybe a third of the voltage drop of 14/2 depending on how well you lay out your circuits.

[gfretwell]

It can't be in a "clothes" closet. You also need working space 30" wide x 36" deep, 6'6" high in front of the panel

[RayV]

I do have a wife and two girls so hair dryers are a concern, the monster that the missus uses dims the lights on the whole block when it fires up.

If I understand fixed load correctly the only thing I have that runs all the time is the Radon fan.

Upstairs I have 4 BR and 2 baths. I figure that will be 8 circuits: one outlet circuit for each BR one shared outlet circuit for the 2 baths three lighting circuits (2 rooms per)

Overkill? Ten years from now each of the girls will probably have their own computer, mp3-cell phone chargers, stereo, tv, dvd player, etc. You know the necessities.

[RayV]

I never thought about it that way. That would save a ton of wire and running wires up & down. It would add to the cost of the other stuff like boxes & nuts but they are a hell of a lot cheaper than wire.

Now, how many connections (wire nuts) can you put in a standard 4x4 box? I'm sure it is less than what I would need to get six outlets and a feed line connected together.

[# Fred #]

Panel in "clothes" closets were done all the time in the old days. I have a

1952 vintage house with a panel in the master (non walkin) closet and use to manage a 1970(?) vintage condo with a panel in the closet as well. Also have seen panels located low to ground in stairwells with headroom less than 4'.

Any idea when the NEC start making those panel in closets non compliance for new construction or remodels?

[# Fred #]

I would think so. I use to have a simple program that would calculate voltage drops in volts and in % drop so you don't need to look it up in a table or calculated it. It ask for wire size (or R + jX if you have it) and length, single or three phase, voltage, and power factor.

We use to put in subpanels when there are a few runs (a few runs is subject but a lot of runs, subpanel is the way to go) rather than home run everything from the existing panel. Could be cleaner and cheaper but you'll be the judge.

[gfretwell]

Clothes closets showed up some time in the 80s but there was always language about overcurrent devices not being in the vicinity of easily ignightable materials. (at least 40 years) Bathrooms showed up in 96.

[gfretwell]

Go with the sub panel. 8 homeruns will cost a lot more than even a 6ga feeder and that is overkill. 8ga/40a should be more than enough for what you describe.

[mm]

I meant you could use 14 gauge, unless there is something unusual.

[mm]

So you put two or three boxes in a row, or find a bigger box, or a box designed for multiple connections, if there are such things.

[autobus_prime]

GIYF:

Summary for metal boxes:

A 2 1/8" deep 4" square can take 13 '12 AWG' or 15 '14 AWG'. A 1 1/2" deep 4" square can take 9 '12 AWG' or 10 '14 AWG'.

A 2 1/8" deep 4 11/16" square can take 18 '12 AWG' or 21 '14 AWG'.

Those who prefer plastic can refer to the molded numbers on the box and divide by 2.25 for 12 AWG or 2.00 for 14 AWG. You heathens. :)

I put the wire sizes in single quotes because of the following:

You must allow 1 'conductor' for all grounds together, and 2 'conductors' for each yoked device (duplex outlet, light switch, double light switch on one yoke, Despard device :) )

To join 7 runs of 12-2 cable:

14 allowances - 7 x 2 conductors 1 allowance - all grounds together No devices (junction box)

Total of 15 allowances. You will need a 4 11/16" square box, 2 1/8" deep.

4 11/16" square boxes are man's best friend (but so are ceiling pans in other circumstances. :-) )

I'd actually prefer not to join so many wires in one box, and usually try to have

4 or 5 cables at most.

Cordially yours: A. P. M. F.