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#1
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Will my voltage drop?
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? |
#2
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Will my voltage drop?
in a word, yes.
firstly, I assume you have 15amp circuits throught, which should only run 30' on a #14wire to keep under a 2% drop. Even with 10 amp ciruits you shouln't go over 45' heck jumping to #12 wire won't do it at that distance either, I would recomend following your friends advice. Empress2454 #124457 The best Games a href=http://www.gamestotal.com/Multiplayer Online Games/a a href=http://www.gamestotal.com/Strategy Games/abra href=http://uc.gamestotal.com/Unification Wars/a - a href=http://uc.gamestotal.com/Massive Multiplayer Online Games/abra href=http://gc.gamestotal.com/Galactic Conquest/a - a href=http://gc.gamestotal.com/Strategy Games/abra href=http://www.stephenyong.com/runescape.htmRunescape/abra href=http://www.stephenyong.com/kingsofchaos.htmKings of chaos/abr RayV wrote: 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? |
#3
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Will my voltage drop?
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#4
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Will my voltage drop?
According to RayV :
wrote: in a word, yes. firstly, I assume you have 15amp circuits throught, which should only run 30' on a #14wire to keep under a 2% drop. snip Are you certain about the 30 feet? That wouldn't even get me to the far side of the first floor for one outlet. Yes, 30 feet is more than a bit extreme. 30' of #14 (approx 1 ohm/1000') has a voltage drop of about .96V at 15A. Which is 1%. At 2%, that's 60'. Our codes consider a 3-4% drop permissible - I don't think the NEC is any stricter. Which is over 100' at 15A. But 200' is clearly too far. I wouldn't think twice about using #14 (breakered at 15A) for a general outlet circuit up to 120' or so, and branches to fixed lighting somewhat longer. That said, if there's any fixed/heavy/motorized equipment on it (including a garage door opener or A/C), I think somewhat differently. You have a number of options to finesse this. Subpanels are nice, but of course they have to be accessible. Using 12/3 to get two 15A circuits (shared neutral) "most of the way" (you're talking 200+ feet) and splitting at a box to 14ga is another. -- Chris Lewis, Una confibula non set est It's not just anyone who gets a Starship Cruiser class named after them. |
#5
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Will my voltage drop?
Folks:
My copy of the NEC doesn't actually restrict the voltage drop for residential wiring, but recommends a 3.6v drop in the branch circuit and a 5v drop including both branch and feeder together 'for reasonable efficiency'. Seems to me a circuit coming right from the panel could use the 5v value. These are both for 120v circuits, by the way. (3% and 5% are the values given, I think. I don't have the book on me right now) Using the 3.6 v value, you can run this much 2-wire cable to your furthest receptacle outlet: 15A - 64 ft. of 12 AWG or 40 ft. of 14 AWG 20A - 48 ft. of 12 AWG Unfortunately this adds up pretty quick. Using the 5 v value: 15A - 89 ft. of 12 AWG or 55.5 ft. of 14 AWG 20A - 66.5 ft of 12 AWG I said 'receptacle' because it's not likely that a light would draw the full 15A, and it's easier to predict what the current will be. I don't think too many residential fixtures draw 1800 W. Cordially yours: A.P.M.F. |
#6
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Will my voltage drop?
According to :
Folks: My copy of the NEC doesn't actually restrict the voltage drop for residential wiring, but recommends a 3.6v drop in the branch circuit and a 5v drop including both branch and feeder together 'for reasonable efficiency'. Seems to me a circuit coming right from the panel could use the 5v value. These are both for 120v circuits, by the way. (3% and 5% are the values given, I think. I don't have the book on me right now) When I wrote the electrical wiring FAQ, I believe it went this way in the NEC: you were _permitted_ to have as much as a 5% drop on a circuit, and the utility is similarly required to provide you 240V at the panel +/- 5%. Which works out to the voltage at an outlet being permitted to be as much as approx 9-10% less than nominal. Which is where the nomenclature of "110V" came about - the minimum permissible outlet voltage given permissible voltage drop from the nominal supply voltage. This is not to say that you can't engineer _better_ than that. Eg: circuits driving 1/4HP+ motors should be carefully considered for example. But a maximum 15A circuit run of 30' for #14 is ridiculously short. You'd hardly get to use "normal wire sizes" anywhere in a house, you'd almost always be derated a size or more. [My calculations were based on 1 ohm/1000'. I misremembered, it's 2.575 ohms/1000'. #10 is 1.018 ohm/1000'] -- Chris Lewis, Una confibula non set est It's not just anyone who gets a Starship Cruiser class named after them. |
#7
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Will my voltage drop?
RayV wrote:
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? 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. |
#8
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Will my voltage drop?
How many wires can properly go in a wire nut? If four, you could spin The allowable combinations are written on the box, usually. |
#9
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Will my voltage drop?
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. "RayV" wrote in message ups.com... 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? |
#11
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Will my voltage drop?
mm wrote: 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. 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. |
#12
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Will my voltage drop?
wrote in message ... On Tue, 05 Sep 2006 21:17:19 GMT, "George E. Cawthon" wrote: 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. 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 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? |
#13
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Will my voltage drop?
Will voltage drop be a problem using 14/2 wire on a bedroom circuit
205' feet from the panel? 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. 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? 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. |
#14
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Will my voltage drop?
On Tue, 05 Sep 2006 18:28:11 -0400, mm
wrote: 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. I meant you could use 14 gauge, unless there is something unusual. |
#15
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Will my voltage drop?
On 5 Sep 2006 18:14:29 -0700, "RayV" wrote:
mm wrote: 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. 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. 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. |
#16
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Will my voltage drop?
OP wrote: 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. GIYF: http://www.hubbellcatalog.com/raco/R...?FAM=RacoBoxes 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. |
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