9 Bilge Pump Wiring Tips

Wiring techniques are important when installing a bilge pump due to the fact that the pump and its wiring in often exposed to water. Water, as is commonly known, is an excellent conductor of electricity. Electrical wiring carrying electrical power and immersed in water could not only damage electrical circuits, it can also start fires and even injure or kill anyone touching the water. To ensure that this danger is avoided, there are certain precautions that should be taken to wire a bilge pump.

Tip 1 – Avoid Allowing Wire to Sag into Water

Route wiring that enters or exits from the pump so that it will not sag into the water under the pump. Use ties or connectors to secure these wires and prevent their sagging.

Tip 2 – Use Adequate Wire Size

Depending on the size of your bilge pump, it could draw as much as 15 amps and could require the use of wire as heavy as 8 gauge. Before wiring your pump, check the size of your pump and its power consumption, then install the right gauge of wire to meet these consumption requirements. A pump with a 3,500 gph, for example, might require 8 or 10 gauge wire.

Tip 3 – Use the Right Connectors

To ensure that your electrical connections between pump leads and electrical circuit wires are solid and secure, use crimp-on, step-down connectors.

Tip 4 – Keep Connectors Dry

For wiring that may be exposed to water, you can keep connections dry by running them through heat shrink tubing. To properly use this tubing, place the wire inside the tubing before you make the wire connections. Place the crimped connector in the tube center. Apply heat from a heat gun or flame to then shrink the tubing, being careful to apply heat only when you're sure there are no fumes in the bilge that could explode.

Tip 5 – Install a Fuse

You will need a fuse in your pump wiring to prevent electrical wires from shorting in the event they become wet. To do this, install a fuse holder (in line) to the end of the wire that goes to the battery. To connect your wire ends, use a crimp butt connector.

Tip 6 – Proper Battery-Pump Connections

To maintain constant bilge pump operation, even when you are not in your boat, connect the pump directly to your pump battery rather than running the wiring through a distribution panel.

Tip 7 – Battery Wiring

To connect circuit wires to your battery's threaded posts, use ring terminals. Make sure you use a size that will fit the battery posts. Avoid stripping the wire ends and looping them under wing nuts of the battery. Between the ring terminal and wing nut, insert a washer that is copper, not steel.

Tip 8 – Using a Three-Way Switch

Some pumps have a separate float switch. If your pump has this type of switch, consider replacing it with one that is three-way. This will give you three options: on, off, and automatic.

Tip 9 – Wire Supports

To keep your wire runs adequately supported, install wire zip ties or clamps placed at 18-inch intervals.