Sizing a Fuse or Circuit Breaker for your Campervan or Motorhome
To properly size a fuse or circuit breaker, you'll need to consider the electrical load that will be placed on the circuit. The size of the fuse or breaker should be matched to the electrical load in terms of amperage. A fuse or breaker that is too small will be overloaded and trip frequently, while a fuse or breaker that is too large will not provide adequate protection for the circuit.
To determine the appropriate size for a fuse or circuit breaker, you'll need to calculate the total electrical load on the circuit. This can be done by adding up the wattage of all the devices and appliances that will be connected to the circuit. Once you have the total wattage, divide it by the voltage of the circuit (usually 12 or 240 volts) to find the total amperage. The fuse or circuit breaker should be sized to match or slightly exceed this amperage rating.
For example, if you have a circuit with a total load of 1500 watts, and the circuit is operating at 12 volts, the total amperage would be 1500 / 12 = 125 amps. It is then best practice to add a 25% margin. In this case, you would need to use a fuse or circuit breaker that is rated for at least 150amps
It's important to note that some devices, such as motors and heating elements, can have a high starting wattage that may exceed their normal operating wattage. In these cases, you'll need to use a fuse or circuit breaker that is sized to accommodate the starting wattage of the device, rather than the normal operating wattage.
Overall, properly sizing a fuse or circuit breaker is essential for ensuring the safety and reliability of your electrical system.