Fitting Float Switch

[t08yg2]

I'm wondering if anyone can offer some advice to an electrical novice. I currently have a rule bilge pump set up on a switch, on or off, no auto.

I have bought a rule-a-matic float switch which I'd like to install. For simplicities sake I'm thinking of simply wiring it in series with the bilge pump so when the pump is switched on at the main switch, it only actually comes on when the float switch senses enough water.

The plan is to leave it on and it essentially acts as an auto bilge.

I have a few questions though;

1. What sort of connectors should I use to wire the switch in to the existing wiring for the bilge pump. I obviously need them to be waterproof but have no idea what to look for.

2. Someone mentioned it should be wired into the positive wire coming into the bilge pump, is this right and how do I work out which one is positive (it has two black wires going in/out).

3. Any advice on fitting the float switch. Not all that keen in screwing it into the floor of the bilge as I half expect to put a hole in the hull! Also what level should I have it at compared to the pump.

Any help or advice would be hugely appreciated.

[Gynner]

- Use marine heat shrink connectors.

- The two black wires: connect one end to battery (+) and other to (+) of pump.

- Sometimes switches can get fouled up (or even break) and you may want to retain the ability to switch on pump manually - overriding auto-switch. So I would run them parallel - not in sequence.

- You could use 3M 5200 fast cure to glue switch to hull.

- Position switch (and pump) so that they are at the lowest possible point where water will be gathering.

[Gynner]

And always use tinned wire on a boat...

[Last Tango]

Originally Posted by Gynner

- Use marine heat shrink connectors.

- The two black wires: connect one end to battery (+) and other to (+) of pump.

- Sometimes switches can get fouled up (or even break) and you may want to retain the ability to switch on pump manually - overriding auto-switch. So I would run them parallel - not in sequence.

- You could use 3M 5200 fast cure to glue switch to hull.

- Position switch (and pump) so that they are at the lowest possible point where water will be gathering.

To physically do this you can just connect the two wires to the battery and the "pump side" of the switch but maybe stick an in-line fuse near the battery.
Saves breaking into the wiring in the bilges

[ShinyShoe]

Float switches are not infallible. Consider switch to bypass it to and go manually on if you don't have other means to dump the water like a trunk.

Originally Posted by t08yg2

1. What sort of connectors should I use to wire the switch in to the existing wiring for the bilge pump. I obviously need them to be waterproof but have no idea what to look for.

You may as well have just asked is a Ferrari better than a Lamborghini!

But I think you will get a universal view that screw terminals AKA chocolate blocks are the Lada of electrical connections. Although if that is the case I'm not sure what twisting the wires together and wrapping in tape is...? SoapBox maybe,

Crimp is commonly considered good. For 'waterproof' you'll probably find the jury votes for a heat shrink over wrap with a hot glue inside it. But there will be a guy along to say thats a terrible solution and you need to re-wire the whole boat because he once worked on a sub-marine and you wouldn't be allowed to do it like that on a sub.

If the junction is going to routinely get wet (i.e. is in the bilge) it needs at least an IP67 container to be in TBH.

Originally Posted by t08yg2

2. Someone mentioned it should be wired into the positive wire coming into the bilge pump, is this right and how do I work out which one is positive (it has two black wires going in/out).

They are probably right - although it will work on either wire, its just 'safer' to be on the +ve in case of shorts etc.

If you have a multimeter you could tell. If you don't - get one - you'll need it at some point boat wiring is a PITA

Or follow the wires back - one goes to the battery already the other to the switch and fuse... direct to battery is negative... (or should be!)

Originally Posted by t08yg2

3. Any advice on fitting the float switch. Not all that keen in screwing it into the floor of the bilge as I half expect to put a hole in the hull! Also what level should I have it at compared to the pump.

There was a well known member on here who screwed his Rib to his trailer ...

Hard to know what you are looking at without pics. Every bilge is different...

But you don't want it to switch on before the water level is enough to pump and you don't want 2 ft of water before it switches on... They are commonly very close --- it avoids pitch and roll affecting the switch level and not the pump level.

Make sure thinks like ropes can't accidentally drift under the switch jamming it up and running the pump dry...

[t08yg2]

Thanks for all the advice! I've actually managed to fit the switch this afternoon (though not wire it yet).

I realised that the bilge pump is fitted to a thicker plate on the hull, obviously designed for things to be screwed in to. The switch is now sat next to it, higher than the bottom of the pump making sure that it won't leave the pump dry before switching off.

I have ordered some heat shrink connectors and am now asking friends who has a heat gun I can borrow