Why does it matter which leg an appliance is on?

On 50A RV service, half your circuits are wired to one 120V leg and half to the other. A leg can only deliver its own rated capacity — overloading one leg trips that leg's breaker even if the other leg has plenty of room left.

I'm using a 50A-to-30A adapter — why did my A/C stop working but the microwave still runs?

Adapting down to 30A collapses your RV to a single working leg. Whichever circuits were wired to the OTHER leg simply have no power at all — it isn't reduced power, it's none — until you're back on full 50A service.

Is it OK to briefly exceed a leg's continuous-load threshold?

The 80% continuous-load figure is a planning buffer, not a hard limit — but a leg's full rated capacity (100%) is a hard limit. Treat "caution" as your signal to stop adding more to that leg.

Does using this tool cost anything?

No, the tool itself is free. If you go on to schedule service, our standard diagnostic, labor, and mobile service fees apply.

RV Owner Toolbox

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Free RV Planning Tool

Campground Electrical Compatibility Checker

Will your RV's electrical load actually fit the campsite's shore power? This free tool checks what you plan to run against your RV's cord rating and the site's service — modeling 50A service correctly as the two separate 120V legs it really is, not a simplified single number.

HomeAway Camping serves Katy, Brookshire, Sealy, Hempstead, Waller, Fulshear, and the greater West Houston area from shop locations in Katy and Brookshire, Texas, with mobile service available across the standard service area.

Check Your Load

How this is calculated

50A service is two separate 120V legs — not a single 50A × 120V number. Each leg can deliver up to its own rated amps at 120V; a circuit wired to one leg can never borrow capacity from the other leg.

Adapters never add capacity — connecting a mismatched cord and pedestal limits you to the smaller of the two ratings. Adapting a 50A RV down to a 30A pedestal collapses you to just ONE working 120V leg; whichever of your RV's circuits are wired to the other leg get no power at all until you're back on full 50A service.

Continuous-load derating: a leg is flagged "caution" once its load passes 80% of that leg's capacity — a standard general electrical-code convention for sustained loads, leaving headroom before the hard limit.

Overload: a leg's total must never exceed that leg's full rated capacity — this is a hard rule, not a judgment call.

Campground Electrical Compatibility Checker

Check Your Load

What would you run at the same time?

Leg A

Leg B

Frequently Asked Questions

Your Setup

Results

Notes