Alternative Bilge Pump Wiring ?

[GobyOneGnoby]

Hello everyone,

My name is Steve and I'm new to the forum by way of helping a friend with an 18' Wellcraft Fisherman.

The boat does not have a functioning bilge. The dash switch is missing, the float switch is disconnected and the pump is shot. With that in mind, we decided to start from scratch.

We'd like to wire the primary in the typical Automatic-Off-Manual fashion which is straight forward enough. The back up is a different story. We'd like Manual and Automatic with no Off. Here is a diagram we put together using a SPST on/off switch.

We'd sure appreciate any and all feedback the forum could offer.

Thank you in advance,
Steve

[David M]

No. Run the pos from the battery to a three-way toggle switch that is designed for controlling a bilge pump. It will come with a Manual-Off-Auto three-way toggle switch. The bilge pump switch will also come with a fuse holder. It will also come with an indicator light so you can see when the bilge pump is running...this is important.

Follow the wiring instructions that comes with the bilge pump switch. Gauge the wire correctly using the correct 12 volt DC tables for run and amps. Also use the correct size fuse according to the pump manufacturer.

[GordMay]

Greetings and welcome aboard the CF, Steve.

I'd never have thought to use an "On-Off" switch; but your diagramed circuit will work as intended.

If you're not inserting a fuse into each positive line, make certain that your wire size is very robust for the application (cct length & ampacity).

[daddle]

Make sure you switch is DC rated well in excess of the DC motor load. It is surprising how hard it is on switches turning pump motors off. There's a big arc.

[sailorboy1]

I wired mine basicaly the way you have drawn. The on/off switch is the breaker on my panel. I do have 2 float switches at different levels going to the pump. I of course fused the lione from the battery to the floats.

[Dockhead]

Personally, I like that better than wiring it all through a three-way switch. The problem with the three-way switches is that the pump can be inadvertantly disabled.

Yet another way is a switch which has no "off" position. The original bilge pump on our boat (we've added a couple more) had this type of arrangement. You can manually activate the pump from the nav table, but it's a momentary switch which has no position for disabling the pump. So the automatic switch will turn on the pump in any case.

[sailfish2008]

hi there you should allways use a fuse in the line , i hope this helps you

[Dockhead]

Originally Posted by sailfish2008

hi there you should allways use a fuse in the line , i hope this helps you

If you wire it that way, and it's your main or only bilge pump, I would strongly recommend physically blocking out the "off" position of the three-way switch.

If you don't, and if you inadvertently switch it to "off", or even if it gets accidentally knocked, then you could lose your boat because the float switch can't turn on the pump.

[GobyOneGnoby]

The intent is to eliminate the off feature completely for the reason mentioned. The owner of the boat is forgetful by nature and I can see bad things happening with a three way switch. I'll beef up the wire and use in line fuses so to protect the circuit and to still have the ability to turn of the pump in the event the get stuck on.

Thank you for the welcome and the help!

Steve

[CharlieJ]

I would suggest that you not use the "normal" Auto-Off-Hold for Manual switch and use a On (Auto)-On (Manual) switch with no Off position instead. My reasoning is this: if your float switch fails and you do have unwanted water in the bilge, you must stay by the normal, spring return, switch and hold it in the Manual position to pump the water instead of looking for the source of water ingress. With the On-On switch, the operation of the pump is being controlled by one of two functions of the switch and can not be inadvertently turned off. Hence; the absence of the Off position in my scheme.

To secure power to the pump for service, turn off its circuit breaker or remove the fuse. Speaking of fuses and circuit breakers, ensure that you size these according to
the pump manufacturer's recommendations, and NOT in accordance with the ampacity rating table for the conductor.

Charlie