NEMA TT-30 — 125 V, 30 A Plug & Receptacle
NEMA TT-30 is a straight-blade configuration per NEMA WD-6: 125 V, 30 A, 2-pole 3-wire grounding. RV shore power (125 V — not a 240 V outlet). The receptacle is TT-30R, the matching plug TT-30P.
No free-licensed face diagram exists for this configuration yet. The specs below still identify it unambiguously.
Specifications
- Configuration
- TT-30
- Series
- Straight blade
- Voltage rating
- 125 V
- Amp rating
- 30 A
- Poles / wires
- 2P–3W
- Neutral
- Yes
- Equipment ground
- Yes
- Max load (at rating)
- 125 V × 30 A = 3,750 VA
- Continuous (80%)
- 3,000 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
RV shore power (125 V — not a 240 V outlet). Family TT overall: rv shore power (tt-30, hot–neutral–ground). Blade geometry keys the voltage family physically: a plug from a different voltage class will not enter this receptacle.
NEMA TT-30 vs the ones it gets confused with
TT-30 vs 14-50
TT-30 is 125 V / 30 A (travel-trailer shore power) — not a 240 V outlet, despite the 3 blades. The bigger 14-50 pedestal outlet is 125/250 V / 50 A. Adapters between them only ever pick up 125 V.
TT-30 vs 10-30
The classic miswire: both are 30 A with three blades, but TT-30 is 125 V (hot–neutral–ground) and 10-30 is 125/250 V (hot–hot–neutral). Wiring a TT-30 like a dryer outlet puts 240 V into an RV.
Common questions
What is the difference between TT-30R and TT-30P?
The letter is the device: TT-30R is the receptacle (outlet), TT-30P is the plug on the cord. Both share the same configuration — 125 V, 30 A, 2-pole 3-wire grounding.
Does NEMA TT-30 have a neutral and a ground?
Yes on the neutral — the 125 V rating means the circuit includes a grounded (neutral) conductor. It carries an equipment grounding conductor (the extra wire beyond the poles).
NEMA TT-30 vs 14-50 — what is the difference?
TT-30 is 125 V / 30 A (travel-trailer shore power) — not a 240 V outlet, despite the 3 blades. The bigger 14-50 pedestal outlet is 125/250 V / 50 A. Adapters between them only ever pick up 125 V.
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