NEC Requirement
NEC 210.11(C)(2) requires a dedicated 20-amp branch circuit for the laundry receptacle (washer). NEC 250.140 requires 4-wire (hot-hot-neutral-ground) terminations for electric dryers — the old 3-wire setup is grandfathered in existing installations but cannot be installed new.
Typical Amperage
20A 120V for washer. 30A 240V for electric dryer. Gas dryers use a standard 120V outlet but the gas line itself requires a licensed plumber.
Receptacle
Standard NEMA 5-20R for washer. NEMA 14-30R for electric dryer (4-prong, code-required since 1996). If you have an old NEMA 10-30R 3-prong dryer outlet, that's grandfathered but upgrading to 14-30R is recommended during any laundry work.
What it costs in Northern Virginia
Typical 2026 pricing
$400 – $900 per circuit
Adding both washer (20A) and dryer (30A) dedicated circuits as a paired job typically runs $700–$1,200 since the runs and terminations can be done together. Replacing an existing 3-prong NEMA 10-30R with a code-compliant 4-prong NEMA 14-30R requires running a new 4-wire cable from the panel — typically $500–$800. Permit and inspection included.
Signs you need a dedicated circuit
- Your dryer outlet has 3 prongs and you're moving in a newer dryer with a 4-prong plug
- The washer and dryer share a circuit (common in older homes) and the breaker trips when both run
- You're moving the laundry to a new location — basement to first floor, or vice versa
- You're going from gas dryer to electric — gas dryers use standard 120V; electric needs new 240V circuit
- The dryer outlet shows scorching, looks discolored, or feels warm during use — overheating connection
- You're remodeling and want to bring the laundry circuits up to current NEC code
Our installation process
- 1
Assessment + load calc
We confirm the existing panel capacity, identify whether the existing dryer outlet is 3-wire or 4-wire, and quote the work — separating washer and dryer if they're on the same circuit.
- 2
Permit pull
Local jurisdiction permit (Fairfax County, Arlington, Alexandria, Loudoun, Prince William, etc.). Filed under our master electrician license.
- 3
Run new cables
Home-run a 10/3 (4-wire) cable from the panel to the dryer location for the new 30A circuit. Home-run a 12/2 cable for the dedicated 20A washer circuit. Fished through walls/ceilings where possible.
- 4
Install receptacles and breakers
NEMA 14-30R for electric dryer (4-prong). Standard NEMA 5-20R for washer. AFCI breakers in the panel per current code; GFCI on the washer circuit (it's near plumbing).
- 5
Inspection
Local jurisdiction inspector verifies the 4-wire dryer termination, GFCI on the washer, and panel work. We schedule and meet on-site.
Frequently asked questions
What's the difference between 3-prong and 4-prong dryer outlets?
3-prong (NEMA 10-30R) is the old standard from before 1996. It carries two hot legs and a combined neutral/ground — which is unsafe because the dryer's metal chassis is bonded to neutral. 4-prong (NEMA 14-30R) is the current code: separate neutral and ground, isolating the dryer chassis from the neutral path. New dryers come with 4-prong cords; old 3-prong outlets are grandfathered in existing installations.
Can I just buy an adapter from 3-prong to 4-prong?
No. Plug adapters that re-bond neutral and ground are technically code violations and unsafe. The proper fix is to run a 4-wire cable from the panel and install a new NEMA 14-30R receptacle. Cost is usually $500–$800.
Do I need a GFCI on the washer circuit?
Yes per current code (NEC 210.8(A) — laundry areas). Older homes with the original washer circuit may not have GFCI; we add it as part of the upgrade. GFCI is critical near plumbing because of the water-electricity proximity.
What about stackable washer/dryer combos?
Same wiring requirements — you need both a 20A washer circuit and a 30A 4-wire electric dryer circuit (or 120V for the dryer half of a heat-pump or vented stackable). The stackable mounting saves floor space but not electrical capacity.
Can I run gas dryer + 240V circuit for future-proofing?
Yes, and we recommend it during any laundry remodel. Adding the 30A 4-wire circuit when the wall is open costs little incremental; doing it later (after the gas dryer is in place) costs significantly more. Future-proofing for electrification (gas-to-electric transition) is common practice in Northern Virginia builds.