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Bilge pump switch on control panel - live on negative


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I have a bilge pump which needed replacing and was. When I took it apart I didn’t pay attention to the wiring (I know). I’ve been told the switch on the control panel is live on negative. Can anyone explain what that means, or better still have a wiring diagram?  
 

Lesson learned for next time!

 

Thanks

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10 minutes ago, Jen-in-Wellies said:

What make/model of pump and float switch? I also don't understand "live on negative".

 

I'm wondering if it means that the switch is in the negative wire (rather than the more usual positive wire) and the pump becomes 'live' when switching on via the negative wire. ?

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9 minutes ago, Alan de Enfield said:

 

I'm wondering if it means that the switch is in the negative wire (rather than the more usual positive wire) and the pump becomes 'live' when switching on via the negative wire. ?

 

If it is then that its the last way I would wire a bilge pump in a steel boat in case of long term current leakage trying to eat the hull. That is unless the pump/switch manufacturer said it had to be done that way. I can just about believe one of the electronic level switches might demand it.

 

 

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Google is your friend. If you type in "Wire up a bilge pump" you will get multiple images showing typical bilge pump wiring arrangement. Also plenty of videos on the process of wiring them up. Just a matter of choosing one that best matches your needs.

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1 hour ago, canalboat77 said:

I have a bilge pump which needed replacing and was. When I took it apart I didn’t pay attention to the wiring (I know). I’ve been told the switch on the control panel is live on negative. Can anyone explain what that means, or better still have a wiring diagram?  
 

Lesson learned for next time!

 

Thanks

I would make the possibly completely erroneous assumption that that means that when the bilge pump panel swith is in the off position, the bilge pump is actually live as connected to the float switch, so if the water rises it will turn on atomatically.  And when the panel switch is in the on position, the pump is switched on manually and pumps the water out whatever the water level is until you switch it off.

 

That would be the equivalent of the usual threeway switch I had on my bilge pump with a built in float switch, auto, off, and manual, except you don't have a completely off switch, which, for a bilge pump, is a somewhat dodgy position. It's worth bearing in mind that whatever kind of bilge pump you have, and whatever kind of float switch, you can be 90% sure that it won't work automatically, so it really cannot be depended on.  Both time mine has been needed, it's failed.

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2 hours ago, Arthur Marshall said:

I would make the possibly completely erroneous assumption that that means that when the bilge pump panel swith is in the off position, the bilge pump is actually live as connected to the float switch, so if the water rises it will turn on atomatically.  And when the panel switch is in the on position, the pump is switched on manually and pumps the water out whatever the water level is until you switch it off.

 

That would be the equivalent of the usual threeway switch I had on my bilge pump with a built in float switch, auto, off, and manual, except you don't have a completely off switch, which, for a bilge pump, is a somewhat dodgy position. It's worth bearing in mind that whatever kind of bilge pump you have, and whatever kind of float switch, you can be 90% sure that it won't work automatically, so it really cannot be depended on.  Both time mine has been needed, it's failed.

 

 

You are correct - this is the setup I had. Apologies to everyone for asking the wrong question. To be fair the person I asked said it "might" be live on negative. 

 

As it's being discussed - what is the best wiring setup for a bilge pump? We would like to be able to manual switch it on from the control panel as well.

 

Thank for everyones suggestions and time.

 

 

 

 

 

 

 

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Main thing is to keep the connections above any potential water level.

In theory, this could be easier by reversing Tony's diagram, with a fused positive direct to pump and the float switch and switch in the negative, but in practice the wires sealed into float switches and pumps are plenty long enough to avoid wet connector problems.

(Surprising number of boats with a taped up choc block connector lying under water, though :( )

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