Wiring Up Your Camper: Who Does What?

Wiring a campervan can be a daunting task, but it's important to get it right to ensure safety and functionality. The wiring is what powers your lights, fans, fridge, and other appliances, so it's crucial to select the correct wire size and type for each circuit. The wire's conductor, which is usually made of copper, allows electrical current to flow. To prevent fires and ensure the wiring doesn't overheat, it's vital to calculate the circuit's current draw and total wire length to determine the appropriate wire gauge.

Additionally, fuses are essential for overcurrent protection in your electrical system. They are designed to blow and stop the current flow if there's too much current due to incorrect wiring, circuit damage, or overloading the circuit. It's recommended to place a fuse at the beginning of each circuit, close to the battery or power source, to minimise potential damage. When selecting a fuse, you should choose a rating that falls between the maximum continuous current of the wire and the circuit's normal current draw.

There are different types of fuses, such as blade fuses, and inline fuse holders to secure them in place. It's also crucial to follow wiring regulations and use stranded wires in campervans to withstand vibrations and movement.

Stranded vs. Solid Wire

When it comes to wiring for a camper, stranded wire is the recommended choice. This is because stranded wire is more flexible and can better withstand the vibrations and movement of a vehicle. Solid wire, on the other hand, is more prone to cracking and is less suitable for this application.

The key differences between stranded and solid wire lie in their construction, flexibility, performance, and cost.

Construction:

Stranded wire consists of multiple thinner wires twisted together into a bundle, while solid wire has a single solid core. Stranded wire is more flexible and can be bent and manipulated more easily. Solid wire, on the other hand, is more rigid and can break if bent too far or too frequently.

Performance:

Solid wire is a better conductor than stranded wire as it has a larger surface area for dissipation. It can also carry more current and is less susceptible to corrosion. Stranded wire, however, has greater dissipation due to the air gaps between the thinner wires.

Cost:

Solid wire is generally cheaper to produce as it requires fewer manufacturing steps. Stranded wire, with its complex manufacturing process, tends to be more expensive.

When to Use Stranded Wire:

Stranded wire is ideal for applications where flexibility is crucial, such as connecting electronic components in tight spaces or twisting and bending to fit intricate geometries. It is often used indoors for electronic devices, circuit boards, and speaker wires.

When to Use Solid Wire:

Solid wire is suitable for outdoor use and applications that require durability and the ability to carry higher currents. It is commonly used in building infrastructure, vehicle controls, and outdoor electrical equipment.

Copper vs. Aluminium Wire

Copper and aluminium are the two most common types of metal conductors used in electrical wires. They are both efficient, easy to use, and affordable. However, there are some key differences between the two that should be considered when choosing which type of wire to use for a camper.

Copper Wire

Copper is the most common metal used in wiring. It is highly conductive, flexible, and thermally resistant. It is also less likely to corrode than aluminium and does not expand and contract as much with changes in temperature. Copper wire is easy to recycle and requires little maintenance after installation. However, it is much more expensive and heavier than aluminium, making it more complex to install, especially over long distances. Copper wire also requires more support over long distances, which can increase installation costs. Additionally, copper wire is often targeted by thieves due to its high value.

Aluminium Wire

Aluminium wiring is lightweight and long-lasting. It is also more affordable than copper, making it a popular choice for large projects or long-distance runs. However, aluminium is more prone to corrosion and cracking, especially when subjected to vibration. It is also more difficult to solder due to oxidation, which can limit its flexibility. Aluminium conductors are larger than copper conductors, requiring larger raceways and increasing costs. When installed incorrectly, aluminium wiring can pose a fire risk due to loosened connections from expansion and contraction cycles. To prevent this, aluminium wire requires an anti-oxidation compound at each terminal point to protect against oxidation caused by moisture and dissimilar metals.

Both copper and aluminium wire have their advantages and disadvantages. Copper wire is a more durable and conductive option, but it is more expensive and heavier. On the other hand, aluminium wire is more affordable and lightweight, but it is more susceptible to corrosion and cracking. For camper wiring, copper wire is generally recommended as it is safer and more reliable, especially in high-humidity environments. However, if cost is a concern, aluminium wire can be used as long as it is properly installed and maintained.

Wire Insulators

• Plastic Insulators: Plastic insulators, commonly made of PVC, offer a range of desirable characteristics such as ductility, electrical resistance, UV resistance, and fire resistance. They are widely used and relatively inexpensive.
• Rubber Insulators: Rubber insulators provide more flexibility than plastic, especially in lower temperature environments. They are resistant to a broad range of temperatures, UV radiation, and wear.
• Fluoropolymer Insulators: Fluoropolymers are specialised insulators that offer excellent resistance to bases, acids, and solvents.

When wiring a campervan, it is important to follow electrical regulations and use the appropriate type of wire insulator. Plastic (PVC) insulated wires are typically used in campervan installations. It is crucial to ensure that the wiring is properly supported and secured to prevent wear and tear due to movement and vibration. Additionally, it is recommended to use anti-chafe tape at metal contact points.

Wire Connectors

One common type of wire connector is the screw/lever connector. These connectors are quick and easy to use, making them a popular choice for campervan wiring. They typically consist of a lever that secures the wires in place by closing it down. Wago, for example, offers lever connectors with 2, 3, or 5 inlets. It is important to note that screw/lever connectors should be covered with heat shrink tubing or electrical tape to insulate the connection adequately.

Another widely used connector is the wire crimp connector. Crimp connectors typically have male and female ends that join two wires together through mechanical pressure or crimping. They create a strong and reliable connection and are available in different colours and sizes to support various current ratings. When using crimp connectors, it is crucial to use a suitable crimping tool to ensure optimal pressure and avoid damaging the wire strands.

In addition to screw/lever and crimp connectors, other methods such as twisting, wire nuts, soldering, and terminal connectors can be used to join wires. However, these methods may have limitations or be less effective in the context of campervan wiring. For instance, wire nuts tend to loosen due to vibration, while soldering may not provide a robust mechanical connection in vehicles that experience rattling or high temperatures.

When selecting wire connectors for a campervan, it is essential to consider factors such as current rating, vibration resistance, ease of use, and safety. Screw/lever connectors and wire crimp connectors are generally preferred due to their reliability, ease of use, and ability to withstand vibrations and movement commonly encountered in vehicles.

Wire Fuses

Fuses are an essential component of any electrical system, including campervan wiring. They are safety devices that protect against overcurrent and prevent electrical fires by breaking the circuit when too much current flows through. Fuses are typically made of metal wire that melts and blows when the current exceeds the rated capacity.

When it comes to wire fuses in a campervan, there are a few things to consider:

Selecting the Correct Fuse Type:

• Blade Fuses: These are the most common type of fuse found in vehicles. They are colour-coded, inexpensive, and easy to replace. Blade fuses include ATO/ATC fuses (1-30A) for small to medium appliances and MAXI fuses (30-80A) for higher-power applications.
• Terminal/MRBF Fuses: These are typically used for fusing leisure batteries and can handle large currents (30-300A).
• MIDI/MEGA/ANL/Class T Fuses: These fuses are designed for high-current applications (30-400A). ANL and MEGA fuses are commonly used in campervan installations.

Sizing the Fuses:

• Fuse size should be based on the wire's ampacity and the current load of connected devices.
• For DC circuits, the fuse rating should be 125% of the circuit's normal operating current. For example, a 20A appliance should have a 25A fuse.
• For AC circuits, the fuse rating should match the wire ampacity to prevent overheating. For instance, a 10 AWG wire should have a 30A fuse.
• Always size fuses to protect the wire. Most amateur installers should use larger wire sizes than necessary for added safety.
• When calculating fuse size, consider the total amp rating of the appliance and add a buffer (e.g., 25%).

Fuse Installation and Placement:

• Fuses should be placed as close to the battery or power source as possible to protect the circuit effectively.
• For DC circuits, fuses can be placed in a 12V fuse box, which is a central point for fusing DC appliances.
• For AC circuits, fuses should be housed in a consumer unit or distribution panel for proper protection.
• In both AC and DC systems, fuses should be installed near the battery to provide full circuit protection.
• Fuse boxes can be combined with AC consumer units to create a sleek and organised installation.
• Always follow regulatory guidelines, such as BS 7671 and NEC, for fuse installation and sizing to ensure compliance and safety.

Frequently asked questions