Navigation Lights Shorting

[Thallac]

I was out on the tidal thames tonight, and the navigation fuse blew.
I took all the bulbs out one by one and tested them individually, after going through that process they worked.
An hour later the fuse blew again, this may have happened when I tired to switch the port engine on with the ignition as I thought it was off, (but it was actually on). At the same time I noticed my chart plotter started blinking every 60 seconds or so. I did not have time to retest all the lights as I needed to get back to SWMBO.
Any ideas of what is causing the fault, or how to test it.
Thanks
Tim

 

[Cloven]

This may help if you have access to Kindle or Kindle App

http://www.amazon.co.uk/Everything-...sr=8-1&keywords=how+to+find+electrical+shorts

 

[knuterikt]

I was out on the tidal thames tonight, and the navigation fuse blew.
I took all the bulbs out one by one and tested them individually, after going through that process they worked.
An hour later the fuse blew again, this may have happened when I tired to switch the port engine on with the ignition as I thought it was off, (but it was actually on). At the same time I noticed my chart plotter started blinking every 60 seconds or so. I did not have time to retest all the lights as I needed to get back to SWMBO.
Any ideas of what is causing the fault, or how to test it.
Thanks
Tim

It's not often that a faulty bulb blow a fuse.
It's more likely to be short somewhere in you cables.
It can be that the insulation have been chaffed of a cable.
You will need to isolate the fault by disconnecting cable and test each individually.

 

[prv]

It's not often that a faulty bulb blow a fuse.
It's more likely to be short somewhere in you cables.
It can be that the insulation have been chaffed of a cable.
You will need to isolate the fault by disconnecting cable and test each individually.

+1

A bulb blowing can sometimes trip a sensitive breaker, but the momentary short is generally too brief to blow a fuse.

Nav light cables, especially on bow pulpits and masts, tend to be squeezed through some hostile environments. Quite likely that there is an intermittent short somewhere.

I have my nav light runs fused individually for exactly this reason - if one goes, a) I still have the others so I can be seen b) I know which cable is at fault.

Pete