30 Amp vs 50 Amp: how many watts each really supplies
Last updated: September 3, 2026
Quick answer 30 A = 3,600 W (120 V × 30 A, one line). 50 A = 12,000 W — because it is
two separate 120 V legs of 50 A each (240 V split-phase), not one bigger wire. Pages that say 6,000 W
are counting only one leg.
The arithmetic (no secrets)
- 30 A service: one 120 V line, one 30 A breaker → 120 × 30 = 3,600 W maximum, all day, forever.
- 50 A service: four conductors — two 120 V "hot" legs of 50 A each, plus neutral and ground → 2 × (120 × 50) = 12,000 W maximum.
- The 6,000 W confusion: if a 50 A RV only uses one leg for a given appliance, that appliance sees 120 V × 50 A = 6,000 W available. But the RV as a whole can draw 6,000 W on each leg simultaneously — that's the 12,000 W figure. Both camps are describing different halves of the same plug.
| Service | Configuration | Max watts | What it realistically runs |
|---|---|---|---|
| 30 A / 120 V | 1 hot leg × 30 A | 3,600 W | One AC + modest extras, with load discipline |
| 50 A / 120/240 V | 2 hot legs × 50 A | 12,000 W | Two ACs, residential fridge, electric water heater, microwave — simultaneously |
| 50 A — single leg view | 1 × 50 A @ 120 V | 6,000 W | What one leg can feed on its own (why some sites say 6,000) |
| 20 A household outlet | 1 × 20 A @ 120 V | 2,400 W | Fridge + lights + fans; AC start surge will trip it |
| 15 A household outlet | 1 × 15 A @ 120 V | 1,800 W | Chargers and a fridge; nothing with a compressor start |
What 3,600 W buys you (30 A budget)
| Load | Running watts | Cumulative |
|---|---|---|
| Air conditioner 13.5k BTU | 1,500 W | 1,500 W |
| Microwave | 1,300 W | 2,800 W |
| Residential fridge | 300 W | 3,100 W |
| TV + chargers | 150 W | 3,250 W |
| Remaining | 350 W — enough for lights, fans, converter; NOT for a hair dryer at the same time as the AC start | |
What 12,000 W buys you (50 A budget)
| Load | Running watts | Cumulative |
|---|---|---|
| Two air conditioners (15k BTU) | 3,400 W | 3,400 W |
| Residential fridge | 300 W | 3,700 W |
| Electric water heater element | 1,440 W | 5,140 W |
| Microwave | 1,300 W | 6,440 W |
| TV + chargers | 150 W | 6,590 W |
| Remaining | 5,410 W — the luxury of not thinking about it | |
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Adapter rules that keep you out of trouble
- 50 A RV → 30 A pedestal: the adapter feeds both legs of your rig from one 30 A source — your whole coach is now a 3,600 W machine. The main breaker inside a 50 A coach (usually 50 A per leg) may not trip before the pedestal breaker does. Run the math, not the breakers.
- 30 A RV → 15/20 A household outlet: a dogbone adapter plus a heavy-duty extension cord. Keep the total under ~1,800–2,400 W and expect a compressor start to trip the household breaker.
- Two 30 A pedestals via "50 A reverse" adapters: a niche trick that gives two 120 V legs — only with GFCI-protected, correctly wired pedestals, and each leg still capped at 3,600 W.
- Wattage is the ceiling, not the goal: generators also lose capacity in heat and altitude (see the generator size calculator).
Where these numbers come from
They are arithmetic from the NEMA service configurations (TT-30P: 120 V/30 A; 14-50P: 120/240 V/50 A) — the same figures published across RV industry training material (NRVTA and similar), reconciled here because the SERP currently disagrees with itself between 6,000 W and 12,000 W for 50 A service.
Related tools & tables
reference
RV appliance wattage chart
tool