220 circuit grounded to floating neutral in sub panel?

[bhuckabee (Brett Huckabee)]

I inspected a sub panel today that had a 220 circuit (for the range) and only 2 conductors with a ground. They connected the ground to the neutral bus (far right side) and the 2 conductors the the 220 circuit (top left) so I’m thinking that in this case the ground is acting as a neutral conductor and the range may not be grounded? Would this be an acceptable configuration or should that ground be connected to the ground bus? Townhouse built in 1985

[Jim_Port]

A 3 wire 240 range was two hots and a neutral. There should have been a jumper on the stove between the frame and the neutral terminal. I don’t remember when the requirement for a 4 wire feeder was added.

[btoye (Bradley Toye, CMI)]

Jim, I always thought it was 2 hots and a ground for older 240v, or does it go either way and not really matter.

[Jim_Port]

Something like an air conditioner or water heater is straight 240/with two hots and a ground. Dryers and ranges are 120/240 where you have neutral current from motors and lights and controls.

[btoye (Bradley Toye, CMI)]

So I guess it does make a difference when a 3 prong dryer or range receptacle is wired to a sub panel. I hadn’t thought about that, thanks.

[sstanczyk (Stephen Stanczyk, WA License #221)]

@Jim_Port

Something like an air conditioner or water heater is straight** 240**/with two hots and a ground. Dryers and ranges are **120/240 **where you have neutral current from motors and lights and controls.

Thanks Jim…

[rmeier2 (Robert Meier)]

For existing installations it is permitted to use the neutral as the EGC for an electric range but the circuit must originate at the service equipment. Since this is a sub-panel it is not permitted. Here’s the 2014 NEC wording:

250.140 Frames of Ranges and Clothes Dryers. 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
connected to the equipment grounding conductor in the
manner specified by 250.134 or 250.138.
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 fol-
lowing conditions are met.
(1) The supply circuit is 120/240-volt, single-phase, 3-wire;
or 208Y/120-volt derived from a 3-phase, 4-wire, wye-
connected system.
(2) The grounded conductor is not smaller than 10 AWG
copper or 8 AWG aluminum.
(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.
(4) Grounding contacts of receptacles furnished as part of
the equipment are bonded to the equipment.

I went back as far as the 1978 NEC which had the same requirement:

250-60(C) The grounded conductor is insulated; or the grounded
conductor is uninsulated and part of a service-entrance cable and the branch circuit originates at the*** service equipment.***

One other note the voltage is not 220 volts but 240 volts as Jim has stated.

[cevans (Chuck Evans, CMI)]

@Robert_Meier

For existing installations it is permitted to use the neutral as the EGC for an electric range but the circuit must originate at the service equipment. Since this is a sub-panel it is not permitted. Here’s the 2014 NEC wording:

I went back as far as the 1978 NEC which had the same requirement:

Good info. I’ll need to watch for these on subs.

[bhuckabee (Brett Huckabee)]

@Robert_Meier

For existing installations it is permitted to use the neutral as the EGC for an electric range but the circuit must originate at the service equipment. Since this is a sub-panel it is not permitted. Here’s the 2014 NEC wording:

I went back as far as the 1978 NEC which had the same requirement:

One other note the voltage is not 220 volts but 240 volts as Jim has stated.

ah yes I knew the 240 don’t know why I typed 220 (208-230 right?) anyway thanks for the info. It was the sub panel config that threw me with that un-insulated ground on the neutral bus.

It looks like because it there’s no insulation that this would be called out unless originating at the SE. If it was an insulated wire it would be acceptable.

I really appreciate all you guys’ help. Grrr, this agent already dislikes me as I recently had a very picky client of hers that went through 4 houses before settling on one that was acceptable.

[Jim_Port]

Brett. That is a neutral .

[bhuckabee (Brett Huckabee)]

@Jim_Port

Brett. That is a neutral .

Yep, got it thank you. I should have wrote “240 circuit uninsulated neutral”

[Jim_Port]

Just an FYI, the neutral is allowed to be uninsulated in SE cable. The neutral or groundED conductor in SE-R will be insulated.

The same is not true for NM cable where the grounding conductor is bare and the neutral is insulated.

[rmeier2 (Robert Meier)]

@bhuckabee

Yep, got it thank you. I should have wrote “240 circuit uninsulated neutral”

I would also add no EGC. Regardless of how you write it up the cable needs to be changed.

[dhawley (Don C. Hawley)]

I doubt the range wire is type SE, most likely this is an 8-2 WG NM (romex) if so the bare ground wire is being used as the neutral and would not be allowed no matter where it originates.

[rmeier2 (Robert Meier)]

From the photo it looks like SE-U cable (upper left).

[Jim_Port]

I too think it is SE cable.