Why use a relay for a campervan pump-switch circuit.
Normally the tap switch contacts would carry the entire 12v current load at start-up. This often causes “arcing” which damages the small points to such a degree that the switch eventually ceases to function. So taps that are wired in line frequently have a short-lived lifetime.
By incorporating this relay into the circuit, helps the taps switch 70 milliamps switch to only energise the relay coil not the pump directly. So the main current is carried by the much more substantial 40 amp rated contacts in the relay, giving you more power to the water pump. So again making your tap live longer.
- 12V 40A 5 PIN
- Changeover relay
- Diode across coil