Grounding wire spliced to neutral conductor

[mjrose27]

I found a junction box that supplies service for an electric oven. The feed conductors did not have an equipment grounding conductor and the wiring from the oven did. They spliced the equipment grounding conductor to the neutral conductor in the j-box. Is this ok?

 

[Frank DuVal]

When were the conductors feeding the oven installed? I forgot the year edition, but before a specific time this was common (NEC OK) practice-shared ground and neutral in SEU feeding ovens/ranges/dryers.

So, not really OK, but approved in years past. Confused?

 

[Pharon]

So, not really OK, but approved in years past.

It's still allowed under certain conditions, per the exception in 250.140.

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 following 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.

 

[kwired]

With cooktops and ovens you often get prewired flexible conduit whips included with the appliance with separate neutral and grounding conductors, you can combine or separate them depending on the application. With free standing ranges you usually need to install the appropriate cord/whip and install/remove a bonding jumper within the appliance depending on the application.