View Full Version : Dryer Circuit
electricman2
05-29-2008, 02:47 PM
Anybody ever run across this? Dryer circuit with 10-2 w/g NM. House built probably mid 70's. Got by rough inspection I guess.
http://home.triad.rr.com/eastdavelec/pictures/resize3.jpg
I see it almost every time I look into an older circuit. Even some new ones.
bradleyelectric
05-29-2008, 02:54 PM
yeah, we used to get by all the roughs like that till maybe 1992. It was normal way to wire a dryer. That is why you can still buy 3 wire dryer cords. For existing homes with a 3 wire plug. You can buy the plugs to replace a broken plug. Notice we didn't have to color the white wire black or red because it was a hot leg. It was assumed that you knew what you were doing if you were working on electrical work.
raider1
05-29-2008, 02:56 PM
Anybody ever run across this? Dryer circuit with 10-2 w/g NM. House built probably mid 70's. Got by rough inspection I guess.
http://home.triad.rr.com/eastdavelec/pictures/resize3.jpg
Quite a common sight in my area. It seems this installation passed in alot of areas.
Chris
220/221
05-29-2008, 03:00 PM
I see it often along with 8-2 NM for ranges.
Now that work has been slowing down I would tell them it's a hazard and run a new circuit :D
I am not sure I see the problem you are referring to. Besides not labeling the white wire. :-?
If it is the three wire wasn't that permitted until the 1996 NEC?
Or I may be overlooking something. I can't make out the picture very well.
220/221
05-29-2008, 03:14 PM
NM as opposed to SE.
It is a technical difference IMHO.
NM as opposed to SE.
It is a technical difference IMHO.
Gotcha. I have seen it done around here as well.
augie47
05-29-2008, 05:05 PM
The oldest Code I have handy is 1990 and the requirement then was an INSULATED grounded conductor unless SE cable was used.
I realize that requirement was often over-looked, but the 10/2 wg would have been a violation in 1990.
Dennis Alwon
05-29-2008, 05:07 PM
Anybody ever run across this? Dryer circuit with 10-2 w/g NM. House built probably mid 70's. Got by rough inspection I guess.
Heck I have done that years ago. 30 years ago my boss said it was okay to do so not knowing any better I did it.
Mea Cupa
LawnGuyLandSparky
05-29-2008, 08:26 PM
This is very dangerous, and makes backfeeding a genset through the dryer receptacle all the more dangerous.
LarryFine
05-30-2008, 12:17 AM
This is very dangerous, and makes backfeeding a genset through the dryer receptacle all the more dangerous. Okay, so when is that not dangerous? When is a double-plug-ended cord okay?
quogueelectric
05-30-2008, 12:28 AM
That is what we call preexisting nonconforming.
quogueelectric
05-30-2008, 12:34 AM
This is very dangerous, and makes backfeeding a genset through the dryer receptacle all the more dangerous.
I know you dont mean male/male we are here to learn more ways to skin the same cat we are cat skinners at best.
iwire
05-30-2008, 06:32 AM
Anybody ever run across this? Dryer circuit with 10-2 w/g NM. House built probably mid 70's. Got by rough inspection I guess.
Quite often and I installed many like that myself before I knew better.
Still not sure why that is wrong but if it was SE it would be OK. :-?
hardworkingstiff
05-30-2008, 06:51 AM
Still not sure why that is wrong but if it was SE it would be OK. :-?
In the 70's in the Tidewater, VA area, 10/2 w/grd NM was not allowed but 8/3 SE (AL.) was allowed. I never understood the difference.
480sparky
05-30-2008, 08:50 AM
In the 70's in the Tidewater, VA area, 10/2 w/grd NM was not allowed but 8/3 SE (AL.) was allowed. I never understood the difference.
In the 10/2, the bare ground wire was used for the neutral. In the 8/3, the neutral would have been covered/insulated.
LawnGuyLandSparky
05-30-2008, 08:52 AM
Okay, so when is that not dangerous? When is a double-plug-ended cord okay?
Sorry, I was being facitious. I should have used this smiley...
http://www.electriciantalk.com/images/smilies/rolleyes.gif
The oldest Code I have handy is 1990 and the requirement then was an INSULATED grounded conductor unless SE cable was used...
What Article for 1990?
220/221
05-30-2008, 12:39 PM
In the 10/2, the bare ground wire was used for the neutral. In the 8/3, the neutral would have been covered/insulated.
I'm thinking he meant 8/2. I haven't seen 3 wire SE....but I have led a sheltered life.
electricman2
05-30-2008, 12:50 PM
Still not sure why that is wrong but if it was SE it would be OK. :-?
Me neither. I just replaced the receptacle and told HO his dryer is back in business.:smile:
LarryFine
05-30-2008, 02:48 PM
I'm thinking he meant 8/2. I haven't seen 3 wire SE....but I have led a sheltered life.Maybe so. :smile:
Like rubber cord, the neutral/ground is counted in SE cable.
hardworkingstiff
05-30-2008, 05:19 PM
Like rubber cord, the neutral/ground is counted in SE cable.
Right, an 8/3 SE cable has a black, black/red tracer, and the strands of neutral/ground wrapped around the black and black/red conductors (at least back in the '70s).
So why was it OK to use the 8/3 SE (Al.), but the 10/2 (Cu.) romex was dangerous?
charlie
05-30-2008, 07:02 PM
The oldest Code I have handy is 1990 and the requirement then was an INSULATED grounded conductor unless SE cable was used.
I realize that requirement was often over-looked, but the 10/2 wg would have been a violation in 1990.
If I am not mistaken, an insulated neutral was always required except for SE cable. Also, the SE cable could not originate from any other panelboard than the main service equipment because of the separation of the grounds and neutrals. :)
mdshunk
05-30-2008, 07:04 PM
If I am not mistaken, an insulated neutral was always required except for SE cable. Also, the SE cable could not originate from any other panelboard than the main service equipment because of the separation of the grounds and neutrals. :)
Yup.
250-60(c) [1987 NEC]
The grounded circuit conductor is insulated; or the grounded conductor is uninsulated and part of a Type SE service-entrance cable and the branch circuit originates at the service equipment.
iwire
05-30-2008, 07:13 PM
250-60(c) [1987 NEC]
The grounded circuit conductor is insulated; or the grounded conductor is uninsulated and part of a Type SE service-entrance cable and the branch circuit originates at the service equipment.
Yes, but the question remains ..... why?
Why is it OK for SE but not NM?:-?
mdshunk
05-30-2008, 07:17 PM
Yes, but the question remains ..... why?
In the wise words of some Madison Avenue employee:
"Why ask why?" (http://www.youtube.com/watch?v=IFSe_oO3Sa8) :grin:
If I was to guess, I'd say that it relates to having bare conductor, being used as a neutral, potentially loosely touching the can of a subpanel.
LarryFine
05-30-2008, 09:17 PM
Yes, but the question remains ..... why?
Why is it OK for SE but not NM?:-?
I'll take a stab at it.
It could be that, when the rule was made, NM cables contained undersized EGC's (i.e., the ones with EGC's), which would not be protected by the branch-circuit OPD.
As for the only-from-the-main-panel rule, it's a dilemma we face when we render a main panel into a sub-panel: where do we land an SE's neutral doing double duty?
We're supposed to replace a cable, receptacle, and cord being used this way, but on the occasion we don't, the bare conductor is connected as a neutral, not as an EGC.
What's the point? I don't know. 8-) Except that an SE cable's bare conductor is clearly designed and approved for use as a current-carrying conductor; an NM's is not.
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