Today we are going to address, simply, the wiring of a submersible 12V water pump, operated by a 12V tap switch. These are great compact units for use in T4s T5s, transits and other similar sized vans.
Electrical tap switches are sensitive micro switches and shouldn’t be exposed directly to twelve volts, so the best and safest way to do this is to wire the pump and switch in series, as shown in the image below.
What this means is that the pump now is operated by earth switching, making or breaking the contact of the earth using the tap switch. In addition to the positive power near water being minimised a further safety master override on the live is provided from the panel. This way your micro-switch is protected and you have easy access to your water.