JohnT Question? 12/3 wire for 220 volt wiring.

I have always ran three insulated wires with a bare ground anytime I am wiring anything 220 volts.

I have electric heaters in the upstairs on my home now and have installed them in several of the rental houses we have.

I always use double pole thermostats and run 12/3 wiring. That wire has three insulated wires and the bare copper ground. The heaters I have installed all had provisions to hook the wires up using the 12/3, meaning: two hots, service return and the bare earth ground.

I alway thought that it was not the safest to just use 12/2 wiring when running 220 circuits. IS the bare ground wire not carrying the service ground current back to the panel????

I will admit to over sizing things when it comes to electric wiring. If it is close at 14g wire then 12g is all the better. At least that was my thinking on the subject.

I have had wiring jobs I have done inspected and non of the inspectors ever complained about me using heavier wiring or additional grounding.

Have I been wrong in thinking that heavier wire and additional grounding is safer????

In your posting you call the third insulated wire a service return and then an additional ground? A pure 220 volt appliance does not need a neutral wire, but if there are any 110 volt devices in it then a neutral is needed. The ground wire only carries current if there is a short in the appliance
No problem in running and extra ground wire but if its insulated it should be tagged green.

On draw bridges we always required a green insulated ground wire in addition to the normal grounds due to the severe corrosive environment.

Its best to always use 3 insulated conductors with grd . In some cases , the grd is covered with a thin green insulation (depending on manufacturer) . Some people take that chance in trying to save a buck by using only 2 conductor with grd . Note : that second grd is an added insurance so you can sleep at night . In my 25+ years as an electrical contractor , I either wired it to my satisfaction safety & code wise or the building owner got some one else who didn"t give a hoot about his work or credibility as a qualified electrician . In my 25 yrs of being in business , I never had a claim against my insurance company or me . Always think of safety when doing electric wiring . HTH ! God bless, Ken

What current on the bare ground wire with a 240V electric heater?
What current on the white insulated neutral with a 240V electric heater?

JD, I just cant from sitting here know exactly whats going on with those heaters.

Normally straight 240 volt appliances (i.e. NO 120 loads) ONLY require the two hots L1 & L2 (red and black 240 VAC) plus the bare/green equipment GroundING conductor so no Neutral white wire isnt even used

You asked "IS the bare ground wire not carrying the service ground current back to the panel????"

ANSWER the bare ground wire does not normally carry any current whatsoever. Its a dedicated isolated conductor for carrying FAULT CURRENT ONLY

The white Neutral is for carrying return current for 120 volt loads AND AGAIN ISNT USED FOR STRAIGHT 240 LOADS

HOWEVER you indicate the heaters have provision for all 4 wires, 2 hots (red black) White Neutral and bare/green equipment ground and if thats so and the inspectors approve it who am I to say (NOT being there) if thats right or wrong?????

John T

John, not an electricitan but a thought. Could that heater be adjustable for a lower heat buy using only a half of it on 110?

Ken,

In other words, anyone who only wires the heater to code is "taking that chance in trying to save a buck" or doesn't "give a hoot about his work or credibility as a qualified electrician".

The trouble with feeling the need to go beyond standard practices and existing code is that there's no real limit. Someone who always used 12 gauge wire where 14 was allowed, 10 where 12 was allowed, etc. could say the same thing about you---you're taking that chance in trying to save a buck, and you don't give a hoot about your work or credibility as a qualified. electrician.

By all means you should do whatever it takes to make you feel proud of your work and able to sleep at night. But you don't need to find fault with the intelligence or the judgement or the competence of those who don't do it your way.

Stan

Whatever ! I didn't say anything about skimping on wire size to save money . I was just trying to help by telling of my past experience as an electrician & using a good grd system . You need to re-read my comment a little closer instead of assuming & jumping on me . One can't be overly safe when doing wiring . Using heavier wire than needed is up to the individual .My past records speak for themself . Nothing to hide or be ashamed of . Also not once was my work questioned by any of the areas inspectors or the (3) power companies I worked with . If a guy doesn't want helpful suggestions or advice , he shouldn't post asking for any . God bless, Ken

My question is what are you hooking the neutral up to on a 220 v heater? Shouldn't be any 110 v part of the heater.

I don't pretend to know as much as the pros on here, but I'm still curious what you would hook the white neutral to- to the best of my recollection, I have never seen a neutral connection on any straight 220 volt appliance.

I just did a 220 "Cadet" type heater for wife's tack room in the barn- ran 12-2 with ground, hooked the black and white to the two hot terminals in the heater and the double-with breaker, put black tape around the white wire on both ends, hooked the bare wire to the green ground screw in the heater and the ground strip in the box, and by that time, I was out of terminals in the heater.

HMMMMMMMMMMMMM I have no idea buttttttttttttt if youre right that sure would provide a good explanation of why it actually requires a Neutral (if indeed it does) since you fer sure need a neutral for 120 so you dont carry normal neutral return current via the equipment ground. Or else maybe it has some 120 volt controls of some sort but I doubt that

Darn good thought

John T

Ok, I was on the job shown by another old electrician to hook both the white neutral wire & the bare grd a different spots of the heater shell to give extra grounding .Its just a practice I learned on a commercial job with this old fellow , so I figure then that if the gentleman felt more confident wiring heaters in that manner & was nice enough to teach me some of his tricks , why not . Like one of the older deceased now inspector said to me , he felt a reassurance with an electricians job when he saw those extra grounds attached even though it wasn't mandatory in some applications. I also liked using the oxiban grease on all connections inside a panel even if the wires were copper . If moisture does happen to get into a panel , copper wires corrode & aluminum wires oxidize . Play it safe was my thoughts . I do hope this helps clear it up more . God bless, Ken

Extra grounds? It's wrong to connect the neutral to the chassis.
The old fellow you respect may have had excellent intentions but a limited understanding of electrical fundamentals.

Hi Ken,

You're right, I didn't have any reason to get on your case about the way you choose to do things. If you feel that those who do not choose to do more than the electrical code requires are cheap and incompetent, you have a perfect right to think so.

The issue of using a larger wire size than the code requires was a hypothetical example of how someone could say the same thing about you. You use two grounds when the code and standard practice only calls for one and you say that people who don't do it the way you do are trying to save a buck or don't care about the quality of their work. My point was that someone else who always used a larger gauge of wire than the code required could accuse you of being cheap or not caring about the quality of your work because you didn't do it his way. Sorry for confusing you, but I have a feeling that that this is not likely to clear it up.

Anyway, you're a really nice man, and if I ever had to have someone else do electrical work for me I would want him or her to be as motivated to do high quality work as you are.

Stan

In the interest of being green by reducing power losses and reducing summer cooling loads. Some building are speced with oversize wire to reduce I2R .

Hi Stan . Thank you so much for this email & the wording was very comforting . I wasn't upset , but I figured the conversation really wasn't getting anywhere , so I didn't respond to the last email I received . You know I kinda over looked the issue about using a latger wire than required , which I think was your point (right) ? Now here's what a couple old timers told me & was verified by the owner & president of the electric supply store I've dealt with since the late 60s . What they all said was , using a heavier guage wire to connect factory prewired electrical devices such as : light fixtures , baseboard heaters , GFI protection devices , ceiling fans plus others that I can't think of at the moment ; was really not neccessrt , plus sometimes difficult because of the difference in wire sizes & space allotted in those devices junction areas .By the time a guy got all the wires twisted together , wire nuted & taped , then you hsve to twist & cramm them all into those small junction ares was all added hrd work . Fixtures are generally wired with 16 guage wire believe it or not . Well I'm very tired so its time for bed .Again thanks for your letter , God bless, Ken

As I understand it the wire gauge should match the amperage, it's not really related to the voltage. But someone please enlighten me if that's wrong.

That's why you have big heavy cables on your battery and little 14g wires on the battery charger.