I have always thought 3 prong oven outlet cannot be extended to new location because 4 prong outlet is required for new or relocation.

However, when I searched on google to verify, I get conflicting result.
Some says it can be done as exception, some says it is illegal and must pull new wire from the panel.

Which is true?

Existing wire is 6-6-6 SE if that makes any difference.

 

An ungrounded circuit cannot be extended. A three wire feed for an oven is normally 2 hots and 1 neutral and therefore ungrounded. A four wire feed is 2 hots, 1 neutral, 1 ground.

If the circuit is existing, it can be used as is.

 

That is what I thought, but someone on different forum says it is allowed as a exception without stating code section.

I also found this thread from 16 years ago (code probable changed since than?) stating it is possible as long is extending SE cable with SE cable.
http://www.doityourself.com/forum/el...onnection.html

 

There is no exception I know of regarding not extending ungrounded circuits. If you were to make the circuit shorter, I could see that being OK. But that is my opinion.

 

I say it's allowed, also without citing code. I'm not an electrician but inspectors have agreed.
My problem with interpreting has always been "new install".
New install to me is installing an electric appliance in a home where no 240 line exists and the builders intended gas.

Edit: I'm not saying this is recommended

 

That is what I thought until now, but now I'm in doubt.

I don't see it any more dangerous than it was before, but I like to do it up to the code when possible. Right now I'm at the borderline of pulling new cable or extending existing cable. Breaker panel is all the was across 2 car garage and have to cut and patch drywall above breaker panel and 6/3 wire ain't cheap. Expecting 50+ ft of wire.

Isn't is considered "new install" when existing installation is altered or moved?

 

When a customer calls me there is no borderline.
If I'm involved in installing a new range, oven or dryer..... it gets three wire plus ground cable.

I HAVE seen what happens when a neutral/ground opens.... the appliance case becomes live. If you happen to get between a live appliance case and and ground.... like a sink... it's all over.

Originally all 240v appliances were 240v ONLY appliances. Now they are 120/240v appliances and in my book that specifies.... a neutral and ground is needed.... regardless of what the code says.

 

You have to agree with Pete but I will say I subcontract for a major nationwide company, very old, and a three wire hook up is authorized.
My butt and theirs is on the line and they have no problem with it.
I've installed many types of electric ranges and they are shipped from the factory in a 3-wire configuration.
4-wire is better, but 3 wire is expected.

 

The NEC is clear, an installation that met code when installed may continue to be used AS IS. IF you alter the original installation, lengthen or shorten the cable, it must then be brought up to the current code.

General rule for remodeling is IF the walls are opened for other purposes then the wiring is also brought up to current code requirements.

There is a however, and it is a BIG however...

HOWEVER, it must ALWAYS be remembered that the NEC is a "model" code and has no power of enforcement. It is ONLY when a local, regional (county) or state legislative body passes a law stating that a model code IS law that the code must be followed. This enabling legislation also has to power to add to or delete from the model code. The legislation states what other provisions must be met such as prescribing permits and penalties. ONLY the local code counts. It is fairly often that legislative bodies are a cycle or two (or more) behind the national model codes.

The result is that the national code may require something that the local code does not. This could be the reason (or excuse) for allowing the ungrounded circuit to be modified in some jurisdictions. It must also be remembered that the individual inspector has a fair amount of leeway when it comes to interpreting the code. Some inspectors are a bit lax, some recognize that certain practices required or prohibited under the NEC are geared more towards contractors and less towards homeowners, and some inspectors are little Caesars when it comes to interpretation.

 

Yes, I experienced it once already but luckily only received a quick tingle as I realized what was happening. I was at my friends home cooking ribs in a large metal stock pot on the stove top. I had taken a pair of tongs (metal) and used them to move the ribs around in the pot. This was with my left hand. As I was doing that I instinctively just laid my right hand down on the counter and my finger just hit the rim of the metal sink and "tingle". But my hand had been sitting on the edge of the metal sink for a few moments prior to the tingle but because the tongs hit the bottom of the metal stock pot it completed the circuit. Needless to say I convinced him to change his set up before someone really got hurt.

 

Let me give an example of extending a circuit and see if anyone agrees.

Double wall ovens can cause problems when installing. The old electric might be at the top and the new oven requires it at the bottom, or vice-versa.
It's hard to convince a customer to rip their house apart when there's a cable right there.

I think that's why they allow some slack in the rules.

 

All depends upon the local inspector, Brian. I know one inspector that would make you tear it all out and redo it. I've known "inspectors" that didn't know their rear from a hole in the ground but because they had the power, they flexed their muscles just to let you know that you had no power unless they gave it to you. MOST inspectors will bend the rules a bit if there is no hazard in doing so.

NEC states that conductors of #6 and smaller sizes may not be re-identified; the reasoning being that it is no hardship to require a contractor to stock several different colors of insulation. I was doing a volunteer job at a non-profit where I ran a four-wire feeder to an outbuilding. I was using #8 to allow the use of some existing conduit and since the run was about 120 feet just bought a single spool of black-insulated wire and cut it into four lengths, taping the ends to identify neutral and equipment grounding conductors. Local inspector didn't have any problem whatsoever with this.

Same inspector, same job site only I was running underground conduit about 150 feet to supply power for a gate operator. For most of the run I used PVC but the risers were in IMC. Same inspector and he took issue with the risers stating the EMT cannot be used underground. I pointed out it was IMC and he apologized but he DID measure the depth of the PVC right at one building and made me add six inches to the riser because the horizontal was not 24 inches below finished grade. Amazingly, when the fence people installed the gate operator they embedded EMT in the concrete and this inspector begrudgingly let it by.

When I re-did the service at my house the "inspector" at first okayed the installation by simply driving by, never actually getting out of his car and (obviously) not signing the permit. I had taken the day off from my paying job waiting for him and it was around three in the afternoon when I saw the power company field engineer. Talking with him He told me the city inspector had already okayed the job and when I pointed out that the permit hadn't been signed he stated that all the city wanted was the money. I (stupidly, in retrospect) mentioned this to my wife and she insisted that I call the guy and demand that he sign the permit. Well, he came out and then proceeded to ding me on all sorts of trivial matters, the one that was the worst being the grounding electrode conductor to the incoming water piping. This was before the requirement that it be made within five feet of the entry of the piping to the house. He was a big guy and the connection was at the front of the crawlspace with the entrance some thirty feet away. He demanded that I move the connection to within five feet of the crawlspace entry. I knew that wasn't a code provision and so I called the power company engineer, he had the same surname as I although not a relation. The power company engineer stated that the city inspector had called him and revoked his prior okay for service. When I told him what the inspector wanted he advised me to do what the inspector wanted if at all possible because he could make lots of trouble for me. Well, it took two more visits before he was mollified and he never did sign the silly permit.

Lots more stories like that.

 

I agree wires can't be re-identified. I'm talking extending a cable with 2 hot wires and an insulated neutral only.

 

Excuse me for being so curt but did you even bother to read what I wrote?

IT IS UP TO THE DISCRETION OF THE INSPECTOR!

Does that help? It is clearly not allowable under a strict interpretation of the NEC. My point is that SOME inspectors will allow it and others won't. There is also the part about the LOCAL code in effect may not be the same as the latest version of the NEC.

 

I think this fact is hurting professionals doing the job right.

I have sub contracted for a builder and management company many times and when I bring up issues not meeting the code, answer from all of them were "forget the code, just make it work at the lowest possible cost".
Doing it right will obviously cost more than doing it wrong, but the builder don't care if it is done wrong as long they pass inspection. I found most of the time, inspectors will pass the inspection without even checking the job.
This make me look like a fool do it right.

 

It's up to you what you do... your ticket's on the line.

 

Let me tell you a bit about the inspector that was a 100% by the book man.

We had a control cabinet for a cooling tower system. This cabinet was supplied by the cooling tower manufacturer and had several motor starters, circuit breakers, control relays and terminal strips for the field wiring. The electrical inspector flat out refused to sign off on the job (total cost of about a half million dollars) because this control assembly did not have a UL approved sticker. The company had to bring in an ETL inspector who looked at the prints and the the cabinet for all of five minutes and then said, "Looks good to me." and slapped on an ETL inspected sticker.

Different job, same inspector. Solid state frequency changers with an output of 200 volts at 400 Hz. The output cables needed to be super flexible so 600 volt welding leads were used. The inspector did not approve it. He said, "Show me where welding lead is approved for use with frequency changers and I will approve it."

Third job, same inspector. Carbon monoxide detector connected to plant air compressor. The low-voltage (24 volts, maybe 10 milliamperes current) alarm wiring was done with 18 gauge common lamp wire. The alarm contacts and terminal board inside the instrument were properly separated from any line voltage terminations. Again, the installation was not approved and the alarm wiring had to all be replaced with no less than #14 THHN wire within conduit.

None of these jobs had any hazard whatsoever from the initial installation but this inspector caused literally thousands of dollars of rework.


Some time later when I was having my teeth scraped the hygienist told me she was going to be calling for the electrical inspection on her new kitchen (Her husband is a contractor and had done the work). I asked her if she had a convenience receptacle on the island and she said no, she didn't want one and there was no reason for one. Since she lived in the same city where this inspector worked I told her that B**** (his name) would not approve it without that receptacle. She was sure she could sweet talk him into approving it but the next time I saw her she was still mad about having to install what to her was a useless receptacle.


Personally, I would rather have an inspector that thinks and is willing to bend a little when the situation is not a hazard than to have to deal with a power mad little Caesar.