School me on winch wiring

[BRE Fabrications LTD]

So I have my winch fitted and had it wired up directly to the battery temporarily so I could get the rope wound on. On Sunday I thought I'd finish off the wiring and mount the isolator supplied.

The plan was to mount to isolator in that gap in front of the battery. I cut a small section of metal plate and drilled a couple of holes on it to mount the switch and then bolt it using an existing bolt to that gap in front of the battery.

With the isolator mounted and wired on the positive side of the winch
I went to connect it to the battery and near enough sh#t myself when it sparked like a mofo. So I turned the switch the the off position and tried again. No spark this time and pants still in an unsoiled condition. Result. Now maybe if I had made the electrikery 101 then I may still have been wary. Next I turned the switch on and it sounded like some one was having a fry up inside the isolator. Feck! Turned it off and fry up stopped.

Now I am confused. As far as I am aware the wiring should be: battery + > isolator > winch +. Battery - > winch -.

The body of the isolator (MBS4 goodwinch supplied isolator) is metal. Should this be able to short the positive to ground? I didn't think it should be able to...

Also the terminals on the isolator seem a bit exposed, it's almost like this should be in an enclosure of sorts.

Help.

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[Towpack]

Looking at a picture of the MBS4 it appears the load and supply terminals are insulated from the metal body. If this is the case it could be the switch you have is faulty. If you have only the + feed from the battery going through the switch the ONLY way it can short out to earth (-) is via the switch body when it's mounted to the vehicle. Easy enough to check if you have a multi/test meter.

 

[Jon Wildsmith]

Use a multimeter to test for continuity between the isolator terminals and battery negative to find out.

 

[Chris]

For info, I took a Goodwinch isolator switch apart and was very surprised to find the insulation between live and the outer body was very very little indeed. Mounted in a non conductive board, you'd have no problems, but in a steel plate,if it takes a bash or such like, I can see how it would fail. I though these were pretty darn good. But I have to say I have changed my mind looking inside one.

Chris

 

[BRE Fabrications LTD]

I didn't think about testing the switch. Will check for continuity between the switch body and terminals tonight.

 

[Chris Green90]

How about one of these??? Looks interesting

http://www.ebay.co.uk/itm/230825055793?_trksid=p5197.c0.m619