What Size Wire for 50 Amp RV Service? A Complete Guide

Installing proper electrical service is critical for powering a recreational vehicle safely and efficiently. Based on the National Electrical Code and standard industry practice, for 50 amps-120/240 volts RV service, the recommended minimum wire size is 6 AWG (American Wire Gauge) copper wire.

What are Gauge and AWG

When working with electrical wiring, it is important to use a proper wire gauge. Wire gauge refers to the physical size or diameter of the conductor metal. The American Wire Gauge (AWG) system is the standard used to specify wire diameters, with higher numbers indicating thinner wires and lower numbers for thicker wires.

For example, a 14 AWG wire is thinner than a 12 AWG wire. Wire sizing is important because it determines the wire’s current carrying capacity, resistance, and durability. An accurate gauge must be used to ensure wires can handle the expected electrical load safely.

Wire Gauge Chart

Here’s a table that includes wire gauge (AWG), maximum ampacity (in amperes), and the corresponding wattage capacity for both 120V and 240V circuits:

Wire Gauge (AWG)	Maximum Ampacity (in Amperes)	Wattage Capacity (for 120V)	Wattage Capacity (for 240V)
14 AWG	15 A	Up to 1440 watts	Up to 2880 watts
12 AWG	20 A	Up to 1920 watts	Up to 3840 watts
1O AWG	30 A	Up to 3120 watts	Up to 6240 watts
8 AWG	40 A	Up to 4800 watts	Up to 9600 watts
6 AWG	55 A	Up to 6600 watts	Up to 13200 watts
4 AWG	70 A	Up to 8400 watts	Up to 16800 watts
3 AWG	85 A	Up to 10200 watts	Up to 20400 watts
2 AWG	95 A	Up to 11400 watts	Up to 22800 watts
1 AWG	110 A	Up to 13200 watts	Up to 26400 watts

Tips

Please note that these values represent the maximum ampacity and wattage capacity for typical applications. Your specific circumstances may require consultation with a professional electrician to ensure safe and compliant wiring.

6 Gauge Wire Specification 

The 6 AWG copper wire has a current carrying capacity of 55 amps per the National Electrical Code (NEC), exceeding the required 50 amps for an RV service. This provides a safety margin for high electrical loads. The cross-linked polyethylene (XHHW) insulation resists heat, abrasion, and chemicals for durability in RVs. 6 AWG’s copper construction maximizes conductivity and flexibility compared to aluminum wire. It meets UL standards with fine, twisted copper strands for redundancy if some are damaged.

Parameter	Details
Size	6 AWG
Number of Strands	19
Cross Section Area	13.3 mm2
PVC Insulation Thickness	0.760 mm / 0.030 inches
Nylon Jacket Thickness	0.130 mm / 0.005 inches
Outside Diameter	6.30 mm / 0.248 inches
Weight	0.109 Lbs. per ft
Allowable Ampacity	55 amps at 60ºC / 65 amps at 75ºC / 75 amps at 90ºC

Electrical Load Calculation

RVs usually use 120 volts for lighting and small appliances and 240 volts for large loads like A/C units. The Amperage is 50 amps. This is the total amount available from the RV service pedestal. 

The formula for load calculation is 

Watts(W) = Volts (V) x Amps (A)

For the 120 Volt loads: 

Watts = Volts x Amps

Watts = 120 x 50 = 6,000 watts

For the 240-Volt loads:

Watts = Volts x Amps

Watts = 240 x 50 = 12,000 watts

Total watts at 50 Amps = 6,000 (120V) + 12,000 (240V)    

        = 18,000 watts

According to the National Electrical Code (NEC), 6-gauge copper wire is rated to carry 55 amps safely. This exceeds the 50 amps RV service requirement. At 50 amps, a 6-gauge wire will limit voltage drop over long runs and prevent excessive heating. A voltage drop can cause damage and poor appliance performance. 

So, based on the electrical load calculations and NEC Ampacity ratings, a 6-gauge wire is the recommended minimum size to supply 50 amps, 120/240 volts service to an RV. Using properly rated 6-gauge wiring ensures safe and efficient power delivery.

Safety Considerations 

When wiring an RV service following factors should be considered for safety purposes. 

1. Fire Risks

Undersized wires can overheat, especially when powering multiple high-draw appliances. Overheated wires greatly increase the risk of catastrophic fires.

2. Equipment Damage

Improper wire gauges cause voltage drops which can damage electronics, appliances, and components sensitive to lower voltages. Air conditioners may not function properly.

3. Loose Connections 

Thinner wires are more likely to come loose from vibrations. This creates arcing/sparking risks, which can ignite fires.

4. Shocks and Electrocutions 

Loose, undersized wires also increase the chances of electrical shocks and electrocutions for those working on or using the RV.

5. Following Electrical Code

The NEC provides wire sizing guidelines for safety. Using the recommended 6 AWG wire for 50 amps RV service avoids all of these risks.

Frequently Asked Questions (FAQs)

1. Can 8-gauge wire handle 50 amps?

Answer: NO, the 8-gauge wire can only handle 40 amps. So, it is not suitable for 50 amps RV service.

2. Can Aluminum Wire Be Used Instead of Copper for a 50 amps RV Connection?

Answer: No, copper wire is strongly recommended. Aluminum is more prone to oxidation and loosening at connections. It also gets work hard, becoming less flexible over time.

3. What Are the Signs of Undersized Wiring??

Answer: Frequent tripped breakers, burnt wire insulation, outlets feeling hot, and devices not working properly can indicate undersized wires.

To conclude 

While a 50-amp RV service may seem straightforward, there are complex technical considerations involved in ensuring safe and efficient operation. It is essential to consult a qualified, licensed electrician for proper installation that adheres to all electrical codes.

Don’t take chances with improper wiring. Following the established guidelines to use 6 AWG wire for a 50 amps RV connection will provide reliable power delivery and peace of mind in keeping your family safe.