New Stove/range

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JoeNorm

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WA
Customer has existing 3-wire with copper SE cable(bare #8 wire for neutral). A new 4-wire run would be nearly impossible.

New stove says "grounded circuit is required." It doesn't give the usual diagram of a 3 vs 4 wire install options like I normally see.

Is a 3-wire circuit not a "grounded" circuit?
 
As far as I know I thought there was an exception to install a 3 wire pig tail on the new stove and use the existing circuit as long as it is the right size. What do you do in a high rise where all the wiring is concealed?

Three wire is still a grounded circuit. You can look at it 2 ways. Your using the neutral for a ground or your using a ground for the neutral.
 
JoeNorm said:
Customer has existing 3-wire with copper SE cable(bare #8 wire for neutral). A new 4-wire run would be nearly impossible.

New stove says "grounded circuit is required." It doesn't give the usual diagram of a 3 vs 4 wire install options like I normally see.

Is a 3-wire circuit not a "grounded" circuit?
Click to expand...

Code permits a cooking appliance to be connected to an existing 3 wire circuit.

If the manual says 'grounded circuit is required', then IMHO it is likely the case that the manufacturer is trying (and failing, see below) to specify a separate EGC. Keep in mind that manufacturer's instructions can require more than what code usually requires, and code requires you to follow manufacturer's instructions.

The issue is that if you have a grounded neutral, then you quite literally have a grounded circuit. Code has very specific examples of ungrounded circuits, and the neutral in a residence is absolutely required to be a _grounded conductor. So regardless of what the manufacturer _wants_, the statement 'grounded circuit is required' doesn't force you to run a 4 wire install.

There might be other parts of the manual that _require_ a 4 wire install.

-Jon
 
I have converted plenty of 3/4-wire appliances to suit the existing location, usually by installing the existing cord on the new appliance. I have also corrected many improperly wired by the delivery guys.

The most involved conversion I did was an older dryer brought to a new home. The dryer was made before the 4-wire requirement, and had no ready means for separating the neutral from the EGC.

I opened the dryer and traced the wiring harness. There were separate white and green wires, so I looked for and found a jumper between them. I cut it and capped the white side, and reassembled it.

I then installed the new 4-wire cord in the usual way, with the white on the neutral terminal and the green on a chassis screw. It was interesting to me that the dryer was wired as if ready to be converted.

But that jumper was buried deep in the harness. :rolleyes:
 
LarryFine said:
I have converted plenty of 3/4-wire appliances to suit the existing location, usually by installing the existing cord on the new appliance. I have also corrected many improperly wired by the delivery guys.

The most involved conversion I did was an older dryer brought to a new home. The dryer was made before the 4-wire requirement, and had no ready means for separating the neutral from the EGC.

I opened the dryer and traced the wiring harness. There were separate white and green wires, so I looked for and found a jumper between them. I cut it and capped the white side, and reassembled it.

I then installed the new 4-wire cord in the usual way, with the white on the neutral terminal and the green on a chassis screw. It was interesting to me that the dryer was wired as if ready to be converted.

But that jumper was buried deep in the harness. :rolleyes:
Click to expand...
I've seen a couple Wolf brand ranges that don't allow this and the cord is not accessible where it goes into the range. Those you couldn't change to a 3 wire and it had a warranty sticker on the back saying not to change it.
 
Is it possible to run a separate ground wire back to one of the allowed sources of grounding? I doubt this is what they meant, but IMO 250.130(C) still applies here. If it is somehow possible to insulate the bare neutral where necessary.

I would do it, if it made sense.
 
I would just make sure it isn't some no-name thing off Amazon that may not be designed correctly.
 
Birken Vogt said:
Is it possible to run a separate ground wire back to one of the allowed sources of grounding? I doubt this is what they meant, but IMO 250.130(C) still applies here. If it is somehow possible to insulate the bare neutral where necessary.

I would do it, if it made sense.
Click to expand...
Thats why I suggested the 10 2 for any new circuit since you can do this
 
Greg1707 said:
Is there not a requirement that the neutral wire be insulated?
Click to expand...
250.140 Exception (3)

Exception: For existing branch-circuit installations only
where an equipment grounding conductor is not present in
the outlet or junction box, the frames of electric ranges,
wall-mounted ovens, counter-mounted cooking units,
clothes dryers, and outlet or junction boxes that are part of
the circuit for these appliances shall be permitted to be
connected to the grounded circuit conductor if all the following
conditions are met.

(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.
 
Greg1707 said:
Is there not a requirement that the neutral wire be insulated?
Click to expand...

In the 3 wire install, the requirement can be summarized as 'the combination EGC/neutral' must be suitable as a _neutral_ circuit conductor.

The bare wire in NM cable is _not_ considered suitable for this purpose.

The bare wire in SE cable _is_ considered suitable.

I don't know if this is a historical artifact, or if there is some requirements difference that makes the bare conductor in SE cable somehow better than the bare conductor in NM. I would note that the bare conductor in SE is regularly used as the neutral for a service.

(Or see the actual code posted at the same time I was writing this post....)
-Jon
 
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