I purchased a of 12/3 with ground at the local big box. The cable and the box were both marked with 12/3 w ground. The cable jacket was yellow. However, according to my wire stripper, the wire gauge is only 14. My stripper works fine on the 12/2 when using the 12 gauge portion.
Is there some rule that allows 12/3 to have smaller conductors? This is the red and black ones not just the white conductor. Has anyone else ran into this?
Replies
It seems to me and my eye that newer 12 gauge is thinner than older 12 gauge. Compare it to some older 12 gauge, take a pic and post it here.
Quantum materiae materietur marmota monax si marmota monax materiam possit materiari?
The insulation on newer 12 guage is thinner than the old, but the actual wire is the same size, as far as I can tell.
Mike Hennessy
Pittsburgh, PA
Probably another Chinese import gotcha.
So far as I know 12 is 12, no matter how many conductors are in the jacket.
The new insulation is thinner (and tougher) as someone else mentioned, i.e., a piece of #12 wire which is 10 YO will have a thicker layer of insulation and will appear to be bigger in diameter - however the actual conductor should be the same.
Old self adjusting stripper getting tricked by the thinner insulation layer maybe? If your stripper is not self adjusting, this theory falls apart.
Jim
Never underestimate the value of a sharp pencil or good light.
If it's 14ga than only use it on 15amp. They will not change the copper dia. even if they change the insulaion. I doubt your strippers lie.
Headstrong, I'll take on anyone!
Edited 10/15/2007 8:55 pm ET by Jemcon
Where'd ya buy it? Maybe its metric.:>)
can you even still use 14-2 ? where you guys are? I know I can't but don't know if it's cause these are apt/condos can you still use it single family home?
this came up today so i sure i couldn't but didn't know the full scope
thanks
p
14-2 and 14-3 is quite commonly used in DE, including new construction, just has to be a 15A circuit.
Single family homes, duplexes, and townhomes (up to 6 units) for sure. I say for sure on these as all have been built and inspected with local HfH chapter in the last year.
Don't know about apartments, condos.
Jim
Never underestimate the value of a sharp pencil or good light.
14-g wire is used extensively throughout the country in residential buildings. There are some local amendments against it in some jurisditions.
The NEC certainly has no prohibition against it, and if it ever does that might be the day I hang up my toolbelt and retire.
Ed
Edited 10/20/2007 12:48 pm ET by edlee
The NEC allows 14 ga MN-B in single family residences. Even in apartments if two stories tall. Local rules may not allow it, but it is fine here in central VA and southern MD.Frank DuVal
As for the original post check the wire size not the insulation.As for code and the use of 14g vs 12g, as far as I know 14g on a 15Amp circuit is allowed but 12g may be required for a long run even on a 15amp circuit. 12g is required for 20-amp but code dictates the size based on circuit amperage and on length of run (voltage drop). So whether or not you can use one size over another depends on the circuit you are running and what is on that circuit. It is not a simple as to 14g for 15-amp and 12g for 20-amp. That is like saying all you need to no to be a plumber is hot on left cold on right and SH** runs down hill.You need to know the run and load on a circuit to determine the size wire you need.
Ya I know what you mean cause you have to include paydays on Friday.
>>It is not a simple as to 14g for 15-amp and 12g for 20-amp.<<
But 98+% of the time in residential electrical wiring -- it is just that simple.
Jim
Never underestimate the value of a sharp pencil or good light.
Sure as far as code goes 98% of the time you are correct but...I see it all the time long run on 15amp circuit to a bedroom or home office at the other end of these McMansions we buid these days. Every thing works but the lights dim a bit when the hair dryer or vac. is on.Of course a sub panel to avoid long branch runs is the better option then to run 12g on 15amp branch runs. But I was just saying that there are times that doing the job right means building beyond what code demands.
>>Of course a sub panel to avoid long branch runs is the better option...<<
You have hit the nail squarely on the head.
However, this may not be economically feasible if it just involved a couple of circuits. In that case, I would run #12 wire and 20A breaker. Meets code and avoids confusion for "those who follow". You get all the benefits and none of the confusion.
Confusion occurs for "those who follow" when they open an SEP and find #12 wire on a 15A breaker, unless permanent explanatory notes are left (extremely rare).
If I were to open a SEP and find this situation -- my assumption would be that someone had, at some point in the circuit, used #14 wire and downrated the breaker to protect it. Better to err on the side of caution.
>>I see it all the time long run on 15amp circuit to a bedroom or home office at the other end of these McMansions we buid these days. <<
So do I and often find the cause is the widespread use of "back stab" connections for outlets.
I have made good money curing / lessening this phenomena simply by removing the outlets in the distant rooms and reconnecting them via the provided screws. In the case of a through branch, I nut line in, line out and a pigtail for the outlet together; then connect the outlet to the pigtails via the screws.
So far, three of the HO's were so impressed with my "cure" they have had me check and/or redo the connections in the whole house. Basically mindless work with a high profit potential.
Jim
Never underestimate the value of a sharp pencil or good light.
Oh yes you are so right about back stabbed outlets the ones that you push in the slot to release that rely only on spring tension for the connection I do not allow these used on my jobs. (yes I know if you use the screws they are fine but the temptation is there to just stab and screw it in so I would prefer these things were off the market.) The kind that clamp as you tighten the screw are OK but, except for GFCI circuits protected buy a GFCI outlet, nut line in, line out is the way to go. It has the added benefit that it makes it harder for the elec. apprentice installing the outlets after the rough-in to screw it up. Personally I like GFCI breaker over GFCI outlets most of the time but the GFCI outlet in theory is easier for the homeowner to test since they see it every day and can see at the point of use if it has been tripped.
And it is obvious (at least at the one outlet) that the outlet is protected by GFCI.Of course now we have AFCI to add to that. How long do you think it will take the inspectors to get up to speed on which areas need AFCI and which do not?I am not an electrician but I do home inspections as well as remodel work so I try and keep up on what is required by code (not just electrical) and what is actually going to be problem free. I see stuff all the time that the building inspectors let go on 2-5 year old construction and new additions. Not to mention the stuff that meets code but is not a good idea to do. Not just electrical but poorly installed vapor barriers (or none at all) bad installation of vent fans, finished basements that are mold problems waiting to happen no HVHC returns in small rooms, cathedral ceilings done by just removing collar ties and without adequate insulation. poor or no flashing the list goes on but that is another thread now isn't it.
I know what you mean about generally shabby work - keeps me in business and booked months in advance.
I have changed enough of the backstab outlets that I custom ground release tool from a cheap screwdriver. Makes my life a lot easier.
Jim
Never underestimate the value of a sharp pencil or good light.
Call the manufacturer or take it back to the store. It's possible they mislabled the wire. If so, there could be others with the same product who are putting nice copper heaters into their walls.
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
If your hair looks funny, it's because God likes to scratch his nuts. You nut, you.
Ok, ya' got me - I had to check.
Highly unscientific sample size - 1 #12 ga. wire each of 2 known vintages.
Old = 1983, unknown brand - from electrical supply house.
New = 2007, Romex Brand from Home Depot.
Old = .1445" OD of insulation, .0795" OD of copper conductor.
New = .1205" OD of insulation, .0795" OD of copper conductor.
That's all I know about that.
Jim
Never underestimate the value of a sharp pencil or good light.
I just checked the tables in the back of my NEC book. For solid #12 wire it says a conductor diameter of 0.081", and 0.064" for solid #14 wire.
12 gauge wire hasn't changed in diameter, and can't change in diameter - that's a definition, not a "nominal" dimension. However, the last box of wire I bought that had yellow insulation was 14 gauge, not 12. Check the insulation on the wire. What does it say?
If it was in a box, it wouldn't be unlikely that someone switched the wire in the boxes, to get the 12g wire at the 14g price. Then later you get the 14g wire at the 12g price. I've run into that with numerous other things.
Tyler.
The yellow cable jacket is supposed to mean 12 gauge conductors inside. 14 is white, 10 is orange. If the actual copper is smaller than 12 gauge, then this is defective wire.
I really like the recent shift to color coding of the NM jacket. Easier for everyone to tell at a glance what they have.
Bill