NEMA L-series twist-lock pinout
NEMA Twist-Lock (L-Series) Wiring
Every NEMA locking connector uses the same terminal code: G (green screw) is ground, W (silver) is neutral, and X, Y, Z (brass) are the hots. Once you read the letters molded beside the terminals, one page covers L5-20 through L21-30.
| Pin | Signal | Notes |
|---|---|---|
| G | Equipment groundGreen | Green terminal screw on every L-series device. |
| W | NeutralWhite | Silver terminal; present only on types with a neutral (L5, L14, L21). |
| X | Hot 1Black | First hot; brass terminal. |
| Y | Hot 2Red | Second hot on 250 V and multi-phase types. |
| Z | Hot 3Blue | Third hot on three-phase types (L21). |
What it’s used for
Twist-locks are how mid-size show loads connect: amp racks on L6-30, distro feeds on L21-30, generator panels sprouting L14-30. The locking ring is the point; a snagged cable de-rigs an Edison but hangs on a twist-lock.
The type number encodes the electrical system: L5 is 125 V hot/neutral/ground, L6 is 250 V hot/hot/ground, L14 is 125/250 V with both hots plus neutral, and L21 is 120/208 V three-phase with neutral. The second number is the amp rating, and no type intermates with another.
Wiring & termination notes
- Wire to the letters, not to blade positions from memory: G to green, W to white, X/Y/Z to the hots. Every legitimate device has the letters molded in.
- On L6 (250 V) types there is no neutral: both conductors are hots and both land on brass. White conductor used as a hot gets re-identified with tape per code.
- Common show table: L5-20 (120 V 20 A: G, W, X), L6-30 (250 V 30 A: G, X, Y), L14-30 (125/250 V 30 A: G, W, X, Y), L21-30 (120/208 V 3φ 30 A: G, W, X, Y, Z).
- The diagram above is a terminal-code schematic, not blade geometry; each L-type has its own keying so mismatched insertion is physically impossible.
Frequently asked questions
What do X, Y, W, and G mean on a twist-lock plug?
NEMA terminal codes: G is ground (green screw), W is neutral (silver), and X, Y, Z are hot conductors (brass). The same letters appear across every L-series type.
Can an L14-30 plug fit an L6-30 receptacle?
No. Every NEMA L-type has unique keying, and adapters between types are wiring devices with real electrical consequences, not passive conveniences. Match the type or build the correct adapter deliberately.