I am an electricain and I cannot find anywhere in the code NEC hand book that has a definition for a cable with conductors. Our boss says a 3 conductor cable with a ground has a total of 3 wires, two blacks and one green. I told him the cable should have 3 conductors plus a ground for a total of 4 wires. Is there a definition anywhere in the code book that would explain this? Thank-you, Ted
Electricain
- Thread starter dodginw
- Start date
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- Location
- Massachusetts
Have you noticed that NM Labeled "12/2 with ground" is a 3 conductor cable and 12/2 rubber cord will have only two conductors?
jumper
Senior Member
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- 3 Hr 2 Min from Winged Horses
Cable/cord designations seems to vary. 12/2 NM w/ ground is 3 wires, while SJxxx cord is marked 12/3 for 3 conductors. Why, IDK.
I do not think the NEC addresses this.
jumper
Senior Member
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- 3 Hr 2 Min from Winged Horses
Never thought of this. Thanks.
The ground is always excluded when referring to cable. There is no need to say 12/2 with a ground MC cable, 12/2 MC cable is all that is needed to order cable. 480sparkys thought does not make sense because the ground in 12/2 MC cable is also insulated, I think that line of thinking only applies to cord.
teco
Senior Member
- Location
- Mass north shore
What about 12/2 MC cable? That has three insulated conductors. I've often wondered what determined this myself.
Sorry to ox110 I'm to late
nollij
Member
- Location
- Washington
I have purchased 3/C cable (3 insulated conductors) for single phase circuits. For 3 phase ungrounded loads, I have ordered 3/C w/ GND cable (GND is uninsulated coper conductor). It just depends on the manufacturer and making sure that you are getting what you need.
I am not aware of any convention for cable labeling.
I am not aware of any convention for cable labeling.
Funny. I order 12/2 MC, and I get a black and a white. I order 12/3, I get black, white, green.
Look at 400.6 (A)type s, so ect,the last sentance
With the type desination ,size, and the number of conductors
in 310.11(A) the number of conductors is not mentioned
jwjrw
Senior Member
Gee sparky you need to oder your MC cable from up here , when we order 12/2 MC we get Black White and Green and we even get a bag of red head's:grin::grin:
Jim W in Tampa
Senior Member
- Location
- Tampa Florida
Just look at the dog tag on the roll of MC. 12-2 will have black white green, 12-3 will have black red white green.And you better check to be sure nobody swiped the red heads as they are not cheap.
SJ cord 12-3 will be white black green
Not saying it sounds right but thats how it works
SJ cord 12-3 will be white black green
Not saying it sounds right but thats how it works
They're not even required on MC so who cares if they are missing or stolen
Roger
Jim W in Tampa
Senior Member
- Location
- Tampa Florida
That depends on the connector. Most seem to have them anymore. As far as wanting them i sure do and demand anyone under me use them. Just added protection to prevent a short.
MC doesn't require anti short bushings regardless of the connector used.
Because they are cheap and the manufacturer simply includes them.
That's you prerogative but not a code requirement.
And I agree.
Roger
jxofaltrds
Inspector Mike®
- Location
- Mike P. Columbus Ohio
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- ESI, PI, RBO
Glad to see the spelling is correct this time. Last time it was spelled perrogative. Not by you.
One of my favorite mis-pronounced words. PRE not PER.
Paul Harvey was the only one that I have ever heard pronounce it correctly.
My favorite mis-pronounced word is military. Laura Logan of CBS News pronounces it Mill-A-Tree.
For some reason (I can understand some of the logic, but not all of it) rommex or MC cable will be 12-3 for bk,rd,wht and green. However a 12-3 cord (being so, sjo,sow, sj etc) will only have bk,wht and green.
I think the practice comes back from the days when BX was used, 12-3 meant a bk,rd,white and an uninsulated ground. Same goes for rommex. So for both BX and Rommex 12-3 meant 3 insulated conductors and the ground was not insulated (as you have to have the EGC), whereas in a cord the ground was insulated. As we moved to MC with an insulated ground, I guess we still kept calling it a 12-3 even though it has now 4 insulated conductors.
However, that's is not an NEC issue. Same way NEC doesn't address whether you call it gutter, or troffer or wireway.
I think the practice comes back from the days when BX was used, 12-3 meant a bk,rd,white and an uninsulated ground. Same goes for rommex. So for both BX and Rommex 12-3 meant 3 insulated conductors and the ground was not insulated (as you have to have the EGC), whereas in a cord the ground was insulated. As we moved to MC with an insulated ground, I guess we still kept calling it a 12-3 even though it has now 4 insulated conductors.
However, that's is not an NEC issue. Same way NEC doesn't address whether you call it gutter, or troffer or wireway.
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