NEMA 18-30 — 3ØY 120/208 V, 30 A Plug & Receptacle
NEMA 18-30 is a straight-blade configuration per NEMA WD-6: 3ØY 120/208 V, 30 A, 4-pole 4-wire non-grounding. Three-phase wye with neutral, no ground. The receptacle is 18-30R, the matching plug 18-30P.
Face diagrams by Comrade Mmirg via Wikimedia Commons, CC BY-SA 4.0 / CC0, unmodified.
Specifications
- Configuration
- 18-30
- Series
- Straight blade
- Voltage rating
- 3ØY 120/208 V
- Amp rating
- 30 A
- Poles / wires
- 4P–4W
- Neutral
- Yes
- Equipment ground
- No
- Max load (at rating)
- √3 × 208 V × 30 A = 10,808 VA
- Continuous (80%)
- 8,646 VA
Load figures are the arithmetic of the device rating at unity power factor. Continuous loads (3 hours or more) are limited to 80% of the circuit rating per NEC 210.19/210.20 — and the branch circuit behind the receptacle comes from the load calculation and conductor sizing, not from the plug face.
Where you meet it
Three-phase wye with neutral, no ground. As a non-grounding configuration it survives only for replacements on existing circuits — new work uses the grounding successor family.
RELATED CONFIGURATIONS
See every configuration on the full NEMA plug & receptacle chart →
Common questions
What is the difference between 18-30R and 18-30P?
The letter is the device: 18-30R is the receptacle (outlet), 18-30P is the plug on the cord. Both share the same configuration — 3ØY 120/208 V, 30 A, 4-pole 4-wire non-grounding.
Does NEMA 18-30 have a neutral and a ground?
Yes on the neutral — the 3ØY 120/208 V rating means the circuit includes a grounded (neutral) conductor. It is a non-grounding configuration: no equipment ground, which is why new installations use its grounding successor.
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