RV Breaker Size: 30 Amp vs 50 Amp Service
Free online tool • 2026 NEC Compliant
Residential RV hookups come in two standard configurations: 30 amp service (120V only, TT-30R receptacle) and 50 amp service (120/240V split-phase, 14-50R receptacle). They are not interchangeable — a 50A RV plugged into a 30A adapter is limited to 30A total, not 50A per leg. Use the calculator below to confirm your breaker and wire size for either service type.
Recommended Sizing
NEC Standard SizeBreaker Type: Standard Inverse-Time
NEC Reference Note: 125% multiplier applied for continuous loads per NEC 210.20(A).
How to Use This Calculator
Identify your RV's service type
Check the RV's power cord and inlet — 3-prong (TT-30) is 30A, 4-prong (14-50) is 50A.
Match breaker to service
30A service uses a single-pole 30A breaker; 50A service uses a double-pole 50A breaker.
Select wire size
30A = 10 AWG copper; 50A = 6 AWG copper, both dedicated circuits.
Install the correct receptacle
TT-30R for 30A service, 14-50R for 50A service — never mix receptacle types.
Frequently Asked Questions
What size breaker do I need for a 30 amp RV outlet?
A 30 amp RV outlet (TT-30R receptacle) requires a single-pole 120V, 30 amp breaker with 10 AWG copper wire. This service provides up to 3,600 watts total.
What size breaker do I need for a 50 amp RV outlet?
A 50 amp RV outlet (14-50R receptacle) requires a double-pole 120/240V, 50 amp breaker with 6 AWG copper wire. Unlike a straight 240V appliance circuit, 50A RV service delivers two separate 120V/50A legs (up to roughly 12,000 watts combined), not a single 240V/50A load.
Can I run a 50 amp RV on a 30 amp circuit?
Yes, with a 50A-to-30A dongle adapter, but the RV's total draw is limited to 30A on a single 120V leg. You cannot run high-draw appliances like two air conditioners simultaneously on the adapted circuit.
Specific Sizing Guides & Calculators
Electric Range Circuit Breaker & Wire Size
What size breaker does an electric range need? Standard ranges require a 40A or 50A double-pole breaker on a dedicated 240V circuit per NEC.
Electric Water Heater Breaker & Wire Size
What size breaker does a water heater need? Standard 4500W electric water heaters require a 30A double-pole breaker with 10 AWG copper wire per NEC rules.
Electric Dryer Breaker & Wire Size
Standard electric dryers require a 30 amp double-pole breaker with 10 AWG copper wire on a 240V circuit. Learn how to size your dryer circuit.
Standard Breaker Sizes NEC & Fuse Ratings
Standard breaker sizes per NEC 240.6(A). Comprehensive chart of standard circuit breaker amperage ratings from 15A to 6000A for residential & commercial.
3-Phase Circuit Breaker & Wire Size Calculator
Calculate 3-phase circuit breaker and wire size. Supports 208V, 240V, and 480V three-phase systems for motors, heaters, and continuous commercial loads.
Hot Tub & Spa Breaker Size (NEC Article 680)
What size breaker does a hot tub need? Most hardwired 240V spas require a 50 amp GFCI breaker with 6 AWG copper wire per NEC Article 680.
Ductless Mini Split Breaker & Wire Size
What size breaker for a mini split AC unit? Sizing depends on the manufacturer's MCA/MOCP nameplate rating per NEC 440, typically 15A to 30A.
Built-In Electric Wall Oven Breaker & Wire Size
What size breaker for a built-in wall oven? Most single wall ovens need a 20A-30A double-pole 240V breaker; double wall ovens often require 30A-40A.
Garbage Disposal Breaker & Wire Size
What size breaker for a garbage disposal? Most residential disposals require a dedicated 15A or 20A 120V circuit with 14 or 12 AWG copper wire.
Submersible Well Pump Breaker & Wire Size
What size breaker for a well pump? Sizing depends on motor horsepower and full-load amps per NEC Article 430, typically 15A to 30A for residential pumps.
Dishwasher Breaker & Wire Size
What size breaker for a dishwasher? Most residential dishwashers need a dedicated 15A or 20A 120V circuit with GFCI protection per NEC 210.8(D).
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