Bilge Pump Wiring

[Zoob]

So I'm thinking of wiring up a bilge pump I have (and separate float switch, unfortunately) this way (see attached image). The intent is that the automatic float has access to power to run whenever it triggers; but also wire it so that I can manually turn it on if necessary, too. Anyone see any issues with how I've laid out the wiring?

Thanks in advance.
-J

 

[saumon]

Re: Bilge Pump Wiring

You're ok. Only one thing: on a boat, groundimg to hull or anything else is a big no-no. The neg of the pump should go straight to the neg battery terminal.

 

[Zoob]

Re: Bilge Pump Wiring

Yup yup - I've actually wired in a switch-box/fuse-panel into my boat, so I can cut power entirely to the battery at a master switch, also. I just drew that for simplicity reasons - but all grounds lead to the battery negative (hard to find a "ground" on a fiber boat. )

Thanks for double-checking/verifying my sketch idea!

 

[83Evinrude]

Re: Bilge Pump Wiring

so I can cut power entirely to the battery at a master switch

I have done the same thing, but the float switch for the bilge pump will have a direct connection outside of the master battery switch. That way if in a marina slip overnight, I can shutoff and remove the master switch knob but the bilge pump still has power to run automatically.

 

[seabob4]

Re: Bilge Pump Wiring

That is the correct way to wire if you don't have a batt switch. One lead off the float constant hot and fused, the other lead combined with the positive off the pump running forward to a on/off switch at the helm...

 

[Fireman431]

Re: Bilge Pump Wiring

NMMA also reads that the float switch on the pump should be wired directly to a hot lead independent of the master switch. Pump should always be ready to turn on regardless of battery settings.

 

[Silvertip]

Re: Bilge Pump Wiring

The ground symbols in the diagram do not imply grounding to the hull. It is a simple way to indicate schematically that the two points are interconnected. Chassis ground is indicated with a very different symbol. Bilge pumps can also be wired with a three way MANUAL/OFF/AUTO switch which is really the preferred method. OFF would be used if the boat is in storage, on a trailer, or on a lift where water in the bilge is not an issue but where a faulty float switch could cause a dead battery by running constantly. With the scheme shown, there is no way to turn the pump off short of popping the fuse or disconnecting it.

 

[mikphilips]

Re: Bilge Pump Wiring

I agree. Your switch seems to only perform the function of cutting the bilge pump ON when the float switch has not done so automatically. You probably already have a switch on your helm that does that. If you are trying to keep your bilge pump from running even when the float switch is activated, you risk the danger of flooding and sinking the boat if you have bilge switched off and you develope a leak.
If you leave your boat in the water and the bilge pump keeps cycling on, then the real problem you have is a leak in the hull or thru-hull fittings. If you have a dry bilge while in the water, then leaks are not creating problem.
If your bilge stays dry while the boat is in the water, then leaving your bilge pump wired directly to battery (thru float switch) is smart, since you want the battery to pump out the water as long as possible if a sudden leak occurs.

 

[Zoob]

Re: Bilge Pump Wiring

I wanted the ability to switch the pump on (in case a sudden leak occurs, and the bilge pump does not have the ability to float up). I wanted to use the bilge pump, but also be able to turn it on in case something has happened to the float switch (example, a heavy railroad tie landed on it, and it can't float anymore).

Never mind the rare chance that a train will fall on me when I'm in the water, though.

The boat doesn't have much at the console, I had to wire it myself. All I had was the steering wheel, an accessory port, and the switch for the bow/stern lights.

It's all wired up, and works like a champ. It's a bit overdone on the fuses, though - there was a fuse right at the console (a fuse panel) as well as the one I put to the positive close to the battery. That's all good.

Thanks again for the input.

 

[Zoob]

Re: Bilge Pump Wiring

Speaking of which - I picked up an 800 GPH pump, and I gotta say - for my little Bayliner -- hooboy, it just DUMPS the water out of the bottom in a blink. I took the garden hose to the inside rear of the boat, put in the plug and let it fill until the float switch kicked in. GULP GULP and two seconds later, it was drained up into the transom. Very fast. Very pleased.

 

[seabob4]

Re: Bilge Pump Wiring

Zoob,
The best advice I can give to owners of small boats is to install the largest bilge pump that will fit! Small boats will fill quicker when waves crash over the gunwales, they have less freeboard to keep spray/waves/wakes out of the hull, they have smaller bilge areas, etc.

And yet you see small boats with tiny little bilge pumps...

 

[Zoob]

Re: Bilge Pump Wiring

She went into the lake for the first time today. All was good, no leaks. A little from the drain plug at the dock, but a quick tightening solved that.

No leaks.

Which means my patching fix for when I drilled two holes through the bottom of the boat (was installing chair posts) held!

Woot

Thanks again for the wiring advice everyone.

 

[seabob4]

Re: Bilge Pump Wiring

"Helping" is a good thing...because one never knows when they'll need help themselves...

 

[saumon]

Re: Bilge Pump Wiring

From the Continuous wave - Whaler site:

http://continuouswave.com/whaler/reference/bilgePump.html

 

[seabob4]

Re: Bilge Pump Wiring

JimH is good, I will give him that. Me and him just seem to have our differences...