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3-wire vs 4-wire dryer and range cords explained
New dryer, old outlet, or the other way around? Here's how 3-wire and 4-wire cords differ and what the code allows.
The breakdown, in plain English
- A 4-wire cord has two hots, a neutral and a separate ground. That's the standard for new circuits.
- A 3-wire cord has two hots and a neutral, with the frame bonded to the neutral. It's only allowed on existing circuits that don't have a ground wire.
- With a 4-wire cord: remove the bonding strap (or green screw) between the neutral and the frame, and land the green wire on the frame.
- With a 3-wire cord: leave the bonding strap in place.
- If your house has a 4-wire receptacle, use a 4-wire cord. Don't downgrade.
Codes to look up
NEC 250.140
Ranges and dryers are grounded with an equipment grounding conductor. Using the neutral to ground the frame is only allowed on certain existing branch circuits.
NEC 250.140 Exception
On existing 3-wire circuits with no ground available, the frame can be connected to the neutral if specific conditions are met.
These are plain-English summaries, not the code's exact wording. Always check the full section in the NEC edition your area has adopted, plus local amendments.
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