Overview

Where ranges or clothes dryers are fed by a 3-wire branch circuit, it is permissible to use the grounded conductor for grounding if an equipment grounding conductor is not present in the box. When services are replaced/modified/upgraded, or transfer switches are installed, the existing load center may end up becoming a subpanel. Previously, this would have required the conductors feeding the dryer to be replaced or upgraded, as the branch circuit was required to originate at the service equipment. The 2023 NEC addresses this issue by rearranging Article 250.140, and includes an alternative to needed to replace the supply conductors in the aforementioned scenario.

Applying the 2023 Code

Article 250.140 has been revised in the 2023 NEC. Two new subdivisions have been added to make the requirements more understandable. Subdivision (A) covers the requirement for the frames of clothes dryers and ranges to be connected to an equipment grounding conductor. Subdivision (B) replaces the exception that was present in previous editions of the NEC, and covers installations where the grounded circuit conductor can be used to ground the frame of the equipment. All of the previous rules still apply, but an additional option has been added. A new provision now permits the grounded conductor in existing branch circuit installations, wired with type SE-cable, to be used for bonding the frame of clothes dryers and ranges- even if it does not originate in the service equipment. The grounded conductor must be insulated or field covered, however. This new provision provides an alternative to replacing the existing branch circuit conductor when the service panel becomes a subpanel.

What’s New for the 2023 NEC?

2020 NEC

In the 2020 NEC Subsection 250.140 read as follows:

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.

2023 NEC

In the 2023 NEC Subsection 250.140 now reads as follows:

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 shall be connected to the equipment grounding conductor in accordance with 250.140(A) or the grounded conductor in accordance with 250.140(B).

(A) Equipment Grounding Conductor Connections.
The circuit supplying the appliance shall include an equipment grounding conductor. The frame of the appliance shall be connected to the equipment grounding conductor in the manner specified by 250.134 or 250.138.

(B) Grounded Conductor Connections.
For existing branch-circuit installations only, if an equipment grounding conductor is not present in the outlet or junction box the frame of the appliance shall be permitted to be connected to the grounded conductor if all the conditions in the following list items (1), (2), and (3) are met and the grounded conductor complies with either list item (4) or (5):
(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 or copper-clad aluminum.
(3) Grounding contacts of receptacles furnished as part of the equipment are bonded to the equipment.
(4) 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.
(5) The grounded conductor is part of a Type SE service-entrance cable that originates in equipment other than a service. The grounded conductor shall be insulated or field covered within the supply enclosure with listed insulating material, such as tape or sleeving to prevent contact of the uninsulated conductor with any normally non-current-carrying metal parts.