NEMA L21-20 — 3ØY 120/208 V, 20 A Twist-Lock Plug & Receptacle
NEMA L21-20 is a twist-locking configuration per NEMA WD-6: 3ØY 120/208 V, 20 A, 4-pole 5-wire grounding. Full wye — events, data centers, distro (L21-30). The receptacle is L21-20R, the matching plug L21-20P.
No free-licensed face diagram exists for this configuration yet — locking faces are not on Wikimedia Commons. The specs below still identify it unambiguously.
Specifications
- Configuration
- L21-20
- Series
- Locking (L / twist-lock)
- Voltage rating
- 3ØY 120/208 V
- Amp rating
- 20 A
- Poles / wires
- 4P–5W
- Neutral
- Yes
- Equipment ground
- Yes
- Max load (at rating)
- √3 × 208 V × 20 A = 7,205 VA
- Continuous (80%)
- 5,764 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
Full wye — events, data centers, distro (L21-30). The locking blades twist in and cannot vibrate or pull loose — the reason generators, stage rigs, and equipment connections spec the L series over its straight-blade cousins.
RELATED CONFIGURATIONS
See every configuration on the full NEMA plug & receptacle chart →
Common questions
What is the difference between L21-20R and L21-20P?
The letter is the device: L21-20R is the receptacle (outlet), L21-20P is the plug on the cord. Both share the same configuration — 3ØY 120/208 V, 20 A, 4-pole 5-wire grounding, twist-locking blades.
Does NEMA L21-20 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 carries an equipment grounding conductor (the extra wire beyond the poles).
RUN THE NUMBERS
Run your whole job on the same numbers
These NORDIX tools are a taste of the full platform — bid pipeline, estimating, and job costing that carry your numbers from the first bid to the final invoice.
See what NORDIX does →