RV Wiring Overview

Oct 23

Wiring an RV can be a bit different from standard home wiring due to the need for mobility, safety, and often working with both 12-volt DC and 120-volt AC systems. Here are some essential tips for RV wiring:

1. Understand Your Power System

12-Volt DC: Powers lights, fans, water pump, etc., when the RV is off-grid (using batteries).

120-Volt AC: Powers appliances like the microwave, A/C, and outlets when plugged into shore power or using a generator.

2. Use the Right Wires

Wire Size: Use appropriate gauge wire based on the current. For 12-volt DC systems, use thicker wires due to voltage drop over distance (e.g., 10-12 gauge). For 120-volt AC, follow the National Electric Code (NEC) standards, typically 14-gauge for 15-amp circuits and 12-gauge for 20-amp circuits.

Color Coding: Stick to standard color coding—black or red for positive (hot), white for neutral, and green or bare copper for ground in AC systems. In DC systems, red is often positive, and black is negative.

3. Circuit Breakers and Fuses

Fuse Panels for 12-Volt: Use fuse panels with individual fuses for each circuit (lights, water pump, etc.). Install fuses close to the battery to protect the wiring.

Circuit Breakers for 120-Volt: Use a breaker panel similar to home wiring for AC power circuits. Each circuit should have its own breaker, and the main breaker should match the capacity of your RV’s shore power cord (30-amp or 50-amp service).

4. Grounding

Ensure all DC and AC circuits are properly grounded. DC systems usually ground to the chassis, while AC systems require a dedicated ground wire connected to shore power.

5. Use GFCI Outlets

For 120-volt systems, especially near wet areas (kitchen, bathroom, and outdoors), use GFCI outlets to prevent electric shock.

6. Install a Converter and Inverter

Converter: Changes shore power (120V AC) to 12V DC to charge your RV's battery and power the DC circuits.

Inverter: Converts 12V DC power from your batteries to 120V AC to power outlets and appliances when off-grid.

7. Label Everything

Label all circuits at the fuse and breaker panels, as well as on the wiring itself if possible, to make future maintenance easier.

8. Test After Installation

After wiring, thoroughly test both the 12-volt and 120-volt systems to ensure everything works as expected. Use a multimeter to check for voltage drops, proper grounding, and continuity.

9. Plan for Future Expansion

When wiring your RV, consider future upgrades like adding solar panels, extra appliances, or additional outlets. Leave room in your breaker and fuse panels for expansion.

10. Safety First

Use proper safety gear when wiring. Disconnect batteries and shore power before working on the wiring.

Secure wires to avoid chafing and damage while the RV is in motion.

Steve Muller