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Posted: Sun Apr 25, 2010 11:55am

Post Subject: Bilge pump again

Last month I asked you about fitting an electric bilge pump. I have now bought a Johnson pump and am now trying to purchase the other bits and pieces required to fit it in the boat. I am having trouble finding a suitable switch. I assume I will need an online waterproof switch but canât find such a thing. Maplin have sold me a toggle switch and a toggle switch cover but I have since realised that it is not waterproof as the wires would be exposed and it doesnât look to be suitable for the job. As the switch will be attached only to the wire and that will be hanging about in mid air (so to speak) is there something you can recommend?


Posted: Mon Apr 26, 2010 8:58am

Post Subject: Bilge pump again

Dear Fran, If you just leave the switch waving about in mid air on the cables I suspect you will be heading for wiring failures and possibly a BSS failure. It could also drop down into the bilge water and hull corrosion is very likely to result. You need to find as way to mount a switch as high as is reasonable possible. Without a photo of the area in which you want to mount the swich I can not be more specific (If you want to email one to by WEDNESDAY MORNING I will be happy to advise further. After that I will be on mobile broadband for a week or so and do not ant to receive large files). Almost certainly fitting a suitable switch will involve drilling holes. You can buy brackets that you screw onto a surface and the fit the switch into a larger hole in the bracket (Look at item EP1 at Your local car accessory shop should have something similar. You might have to enlarge the centre hole to suit the switch you have. If you can mount the switch with the terminal pointing down. If you have any suitable vertical surfaces you can drill a larger hole through one of them and fit the switch into that. Try to put the terminals on the most protected side. If the switch you have been sold is Maplin number JK something then it is perfectly suitable BUT when you come to select the push on terminals you will be crimping onto the wiring please use fully insulated ones like VWP no. BFF6. If your switch is fitted with small terminal screws you can still use it (subject to its current capacity) but expect corrosion problems at the screws in the longer term. Your pump should have a long cable on it. Run this as high as you can so its end is well clear of bilge water and then it will be easiest for you to use two sections of what is known as a "choc block" connector to attach the extra wiring you will need. (VWP no. CB2.5). If the pump has an automatic float switch you will need three sections of connector and a centre off three position toggle switch. In that case I hope the pump supplier has given you a wiring diagram, if not email me and I will draw one or you. IF this is a new installation of a bilge pump you will almost certainly also require a fuse close to the point where you pick up the live feed unless the feed is already fused. If it is make sure all the cables you fit are rated to carry the fuse current or greater. If the pump has an automatic float switch the live feed can be taken from the battery side of the master switch and it will need fusing. Otherwise it should be taken from somewhere on the switched side of the master switch. Personally I would feed an automatic pump from the domestic batteries so it can not flatten the engine start battery. Please remember it is extremely bad practise to leave wires dangling about, you should find a way of securing them every six inches or so. Tony Brooks

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