Electrical connection problem

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landyhubbard

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Advice please. My pulpit-mounted navigation light is not working. I have checked the bulb and its OK, and I have voltage at the pins of the lamp-holder according to the multi-meter and I have cleaned the base of the bulb and the pins, but still can't get the light to work. I have swaped the bulb-holder fior a spare, still no joy. The only thing that I can see that might be a problem is that the wire to the lamp is pretty black, even when cut well back, but I have cleaned the ends well. Could the multi-meter be reading voltage but with a problem further upstream that is causing a malfunction? I am steeling myself to replace the wireing back to the switchboard, a hell of a job as it runs through the deck and up inside the pulpit.
 
Run a temporary spare cable direct from the battery (or other convenient take off point ...) that'll prove that it is your cable that is knackered ...
 
I think the wires might be corroded enough so that they can't carry any current. When you measure with a multimeter there's 12v but as soon as you put some load on the wiring it drops to 0. Try measuring the voltage with the lamp in its socket. Does touching the bare wires to the bulb light it?
 
Re: Electrical connection problem

Check if you still have a voltage with the bulb in, you may have a resistive joint, it will give a voltage at the low meter current, but not the bulb.
Try a temp cable on deck to by-pass the original, if the bulb lights, afraid it's your wiring.

Brian
 
What voltage are you getting?? Anything below 11V or so and the bulb probably wont work or be very dim at best; if you have a steady & decent voltage at the contacts it should be ok. Blackened wire means they used non-marine wire originally and blackening is oxidation of the unprotected copper; it will carry less power and become brittle in the process; ulitmately it needs replacing.
 
Sounds like I might need to replace the cable run. If the light needs a 30' cable run and has a 10w bulb, what size cable would I need? and could forum members advise on a supplier of tinned twin cable. thanks for your help guys.
 
If you do replace - a tip.

Once sailed a Swan that had the nav light cables running forwards to a position inside forecabin lockers, where they terminated at connectors. Separate cables ran from the pulpit lights through the legs and down into the forecabin, where the connction was made. Reasoning was that the external cabling was most exposed to damage and corrosion and was likely to need replacing from time to time, where as the internal cabling was warm and dry and should last for ever (sort of). So provison was made for doing the easy part of the recablng, without needing to run a cable three-quarters of the length of the vessel.
 
I have just sorted a similar problem, which is this case was a mast multiconnector, coevering tricolour, steaming light and deck flood light. When the MCBs were all switched on, the indicators bulbs came on, but nothing worked. Checked the plug and go 12 volts on each pin, measured the resistance of the three mast circuits all all OK. Connected temporary 12 volt flying lead to each circuit on the plug and the system worked fine.

Threw away both plug and socket, replacing with new. All working perfectly.

Has a previous problem with same plug/socket combination with a solar panel, where input voltage via the plug/socket was 15 volts, and the output was about 3 volts.

Memo to brain - dont use this make of plug & socket again
 
Re: Electrical connection problem

What type of multiconnector did you replace the duff one with ?
I have had a lot of failures with these.

thanks
 
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