When planning your campervan’s electrical system, you probably spend a lot of time thinking about batteries, solar panels, and inverters. But there’s one important detail that can have a big impact on both your budget and how smoothly your system runs: the length of your electrical circuits.
The longer the distance between your battery and key components, the thicker—and more expensive—the wire needs to be. This applies not only to your main components like batteries and inverters, but also to power-hungry appliances like water heaters and induction cookers. While the wiring for smaller devices like lights and fans doesn’t cost as much to increase in size, it still makes sense to keep wire runs short when you can.
In this article, we’ll explain why it’s essential to keep major components and heavy-load appliances close to the battery, how circuit length affects the cost of your wiring, and practical tips to help you design a cost-effective system.
How Circuit Length Affects Wire Size and Cost
In any campervan electrical system, circuit length directly impacts the thickness of the wire required. The longer the circuit, the thicker the wire you’ll need to maintain safe and efficient power delivery. But not all wiring is created equal, and it’s important to understand which circuits are driving your costs.
Main Components Need Large Wires
The heavy-duty parts of your system—batteries, inverters, chargers, busbars, and fuses—are the ones that require thick cables. These components handle high currents, so even when they’re located close together, they need large wires to safely carry the load. But the further apart they are, the thicker (and more costly) those cables need to be.
Distance Increases Costs Dramatically
The longer the run between your main components, the more resistance builds up, meaning you may need thicker cables to avoid performance issues like voltage drop. This is where the real cost increase comes in. Plus, keeping these thick expensive cables short means you can make pretty hefty savings.
Key Components to Keep Together
- Battery
- Inverter
- Chargers
- Busbars
- Fuse Boxes
Keeping these components close together reduces the need for large, expensive wires and improves system efficiency.
Appliance Wiring Still Matters
While the wiring for most appliances like lights and fans doesn’t usually require large cables, it’s still important to consider placement when it comes to power-hungry appliances. Devices like water heaters, induction cookers, or high-powered air conditioners draw a lot of current. Placing these appliances closer to your battery or distribution points can reduce the need for thicker, more expensive wires.
Even though appliance wiring is generally smaller than that required for your main components, it can still become a factor when appliances pull high loads over long distances. Keeping wire runs short for these devices where possible helps keep your overall system cost-effective.
Power-Hungry Appliances to Keep Close to the Battery
- Induction Cookers
- Water Heaters
- Air Conditioners
Shorter circuits mean thinner, less expensive wires!
Why It’s Important to Keep Main Components and Heavy-Load Appliances Close Together
Keeping your main components close to each other is one of the easiest ways to reduce wiring costs in your campervan, and the same applies to power-hungry appliances. Here’s why:
- Main Components: Your battery, inverter, fuse box, and chargers should ideally be grouped together. This keeps the high-current wires short, reducing the need for expensive, thick cables.
- High-Power Appliances: Appliances like induction cookers or water heaters benefit from being closer to the battery and other key components. These devices draw a lot of power, so shorter wire runs mean you can use thinner, less expensive cables to connect them.
- Avoid Long Heavy-Duty Runs: If you have a water heater placed at the opposite end of your van from your battery, you’ll need a much thicker wire to handle the load over that distance. But by keeping it closer, you can reduce the wire size, cost, and complexity of your installation.
A Practical Example
Let’s look at two different setups to highlight the price difference.
In the first scenario, you’ve placed your battery at the rear of your van, your busbar and other major components in the middle, and your water heater near the front. The cable run between the battery and busbar is 1 metre, meaning a 2-metre circuit in total. The run between the busbar and water heater is 3 metres, giving you a total circuit length of 6 metres. You’ll need a 120mm² cable between the battery and busbar at £32.45 per metre and a 16mm² cable to the water heater at £5.63 per metre.
In the second scenario, let’s say you move the busbar closer to the battery. Now the cable run between the battery and busbar is just 0.25 metres, for a total circuit length of 0.5 metres. The run between the busbar and water heater is now 3.75 metres, so the full circuit is 7.5 metres. You’ll still need 120mm² cable between the battery and busbar, but now you’ll need a 25mm² cable for the water heater at £8.56 per metre.
In the first scenario, where the busbar is positioned in the middle of the van, the total cost for the wiring is £98.68.
In the second scenario, where the busbar is positioned closer to the battery, the total cost for the wiring is £80.43.
By placing the busbar closer to the battery, you save £18.25 on wiring costs, despite needing a thicker cable for the water heater. This shows how careful positioning of your components can lead to cost savings.
Minimising Costs Without Compromising Quality
While the wiring for smaller devices like lights, fans, and outlets doesn’t usually require large cables, the placement of high-power appliances like water heaters and cookers is crucial. By grouping these appliances and components near the battery, you’ll minimise the need for thick, expensive wires and reduce the overall cost of your electrical system.
To sum it up:
- Main components like batteries, inverters, and chargers need thick cables, and the longer the circuit, the more costly those wires become.
- High-demand appliances like induction cookers and water heaters can also benefit from being placed closer to the battery to keep wire sizes and costs down.
- Smaller appliances don’t need thick wires, but even a small increase in wire size can start to add up when considering multiple circuits.
Need Help with Your Electrical Layout?
Figuring out the best way to lay out your campervan’s electrical system can feel overwhelming, especially when you’re trying to balance efficiency and cost. If you’re not sure how to place your components and appliances to keep circuit lengths short and wiring costs down, we’re here to help.
Our campervan electrical design service takes all of these factors into account, helping you optimise the layout of your main components and high-power appliances. We’ll make sure your system is both cost-effective and efficient, giving you the peace of mind that your van is set up for success.
FAQs
There are wire size calculators available online that can help you estimate the right gauge based on the current your appliances draw and the length of the circuit. We also offer guidance during our design consultations to ensure your system uses the correct wire sizes.
Yes, but placing appliances further from the battery will require thicker and more expensive wiring to maintain safety and performance. We recommend placing power-hungry appliances, like water heaters or induction cookers, as close to the main components as possible to save on costs.
Using a wire that’s too thin can cause voltage drop, which affects the performance of your appliances. In extreme cases, it could also lead to overheating and safety risks. That’s why it’s important to size your wires appropriately based on the circuit length and the power drawn.
Smaller appliances typically don’t draw enough current to require large cables, even over longer distances. However, keeping these circuits short where possible can still help reduce material costs and simplify the installation process.
Conclusion
Circuit length plays a big role in determining the cost and complexity of your campervan’s electrical system. The longer the wire runs between your battery and key components, the thicker (and more expensive) the wire needs to be. By keeping your main components close together and placing power-hungry appliances like induction cookers and water heaters strategically, you can reduce wiring costs and simplify installation.
If you need help designing your system or just want advice on how to optimise your layout, our campervan electrical design service can help you build a system that meets your needs without blowing your budget.
Here’s to an efficient, cost-effective electrical system and smooth travels ahead!
