Fuses and cable sizes: what is mandatory

Every power cable in the Camper Jarvis system needs its own fuse in the cable, even though all devices already have self-resetting fuses inside. The reason: the fuse in the cable protects the cable, not the device. Without it, a damaged cable could get hot.

Which fuse goes where

• SmartKnob: a 2A fuse in the positive cable, close to the battery.
• Volty Pro and Fluidy Pro: a fuse in the positive cable, matched to the cable size. The modules themselves need well under 1A.
• Switchy, channels for 12V and 24V: each connected device needs its own fuse, no more than 30cm from the positive terminal of the battery (according to DIN EN 1648-1).
• Switchy, channels for 230V: upstream an RCD with 30mA and a B10 circuit breaker (MCB). Only a qualified electrician may install these. More on this in Why a B10 circuit breaker is needed at 230V.

Which cable size?

The more current flows, the thicker the cable has to be. As guide values:

If a cable is longer than 3m, also check that no more than 3% of the voltage is lost along the way. Long, thin cables cost voltage, and then too little arrives at the device.

Basic rules for all devices

• Only connect to the leisure battery, with 9 to 36V DC. Never to the starter battery.
• Red is positive, black is negative. All devices are protected against reverse polarity.
• Sensor cables no longer than 3m.
• Route cables away from heat, sharp edges and moving parts.