Electrical Wiring in the Home/Does my 240V wiring meet code for new range?
First off, thank you for volunteering your time and expertise with us. Your help is very much appreciated!
I am replacing a circa 1982 Jenn-Air range. It was originally hard-wired with three wires on a 40A circuit.
My new range includes wiring options for either 3- or 4-wires (with the difference being the inclusion of a jumper from neutral to ground in the case of a 3-wire install).
What I'm not sure about is whether the existing cable meets the criteria in 250.140. Specifically, "(3) the grounded 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."
I know the circuit originates at the panel. However, I don't know if the cable is SE. It has an outer plastic sheath, a black, a white, and a bare (all stranded). Can you tell from that description? What characteristics define an SE cable?
The ultimate question I'm trying to answer is, "Do I have a code-compliant option for wiring my range with the existing circuit, or do I have no option but to have a new 4-wire circuit run?" (I'm aware that the 4-wire option would be better, but the quote I have in hand is already more than the price of the range and does not include the sheetrock repair and repainting that will be required to complete the job. I will do it if it's the necessary thing to do, but I don't want to do that if there's a code-compliant alternative.)
The electrician who quoted the 4-wire circuit couldn't explain the situation to my satisfaction. He wouldn't come out and say "your situation does not meet code". Instead, his rationale was "you need 4 wires because your range has digital controls". That makes no sense to me...the manufacturer clearly indicates that a 3-wire install is an option.
From your description it sounds like you have "Romex" with a bare stranded "grounding" wire that runs inbetween the black and white wire.
SE cable also has a bare wire but it is "braided" or woven around the outside of the two conductors and when you skin the end to terminate it you must take all the individual bare wires in the "braid" and twist them all togther to make one wire. If the cable you have is not like this then unfortunately you can't use it for the new range. The difference is this: The braided wire in SE cable can be used both as a current carrying conductor for "neutral" current and as a "grounding" conductor for short circuit current in the event of a "short". However SE cable of this type can only be used to hook up a NEW range if its an EXISTING installation. In other words the old range was hooked up to it. So if you had this type of cable you could have used it. But for a new installation from scratch a 4 wire cable would have to be run and unfortunately it seems thats what your looking at. The bare ground in the Romex you have is not approved for use as a current carrying conductor to the stoves components. The only time it can have current on it is in the event of a short circuit.
Just for the record you don't need 4 wires for digital controls and the manufacturer is correct that a 3 wire hook up will suffice as long as it was connected to the old stove and your reusing it for the new stove.
---------- FOLLOW-UP ----------
Yes, your description of an SE cable does not match what I see. My cable is flat (like Romex) and the uninsulated wire is a solid conductor (I was mistaken when I originally said it was stranded) that runs in-between the two insulated conductors inside the jacket--I was able to take a photo and attach it this time. Sounds like the right thing to do is to pull a new cable. Not the answer I was hoping for (rats!), but I sincerely appreciate the help.
I have one more question, out of curiosity: This cable _was_ connected to my old range. Do you happen to know if that met code in 1982, or was that a poor choice by the builder? (Like I say, only curious, so if you're not sure, please don't spend any effort looking it up!)
Thank you very much,
Yup thats "Romex"
Yes in order to be code compliant and covered insurance wise if anything were to go wrong you have to run a new 4 wire cable.
The bare "grounding wire" in Romex has never been approved for use as a "current carrying conductor" so unfortunately you can't get that one "grand fathered" either.
It was the wrong choice by the electrician.
Its really a technical matter because the solid bare "grounding wire" will work just as well as the braided wire in the SE cable but it doesn't have the dual rating. But electricians know or should know that this wire under normal circumstances does not have current on it so if some one were to use it that way you could be putting some one at risk whos not expecting that then goes to disconnect the wire and gets a surprise.
Look at it this way Jim you'll be stimulating the economy