Steaming light short...?

[malyea]

The steaming light halfway up the mast on my '82 H30 does not work - the masthead anchor light works fine.

A friend went up the mast and tested for power at the fixture - there was none. We tested the circuit breaker and it checks OK. We suspect there is a short in the wire - just don't know where. I'd like to find and fix it rather than install a workaround temp solution and it prompts me to ask a few related questions...

My friend suspects that in the past the mast was removed / resteped and that the wires were pinched at the base creating the short - I'd like to do more troubleshooting to make sure before we unstep the mast and find that's not the short location.

How best to trouble shoot the exact location of the short?

Did my H30 come factory wired with both the masthead anchor light and the steaming light installed as standard?

At the base of the mast, there is not an inspection plate nor do the wires exit the mast anywhere above deck near the base of the mast - so - how are the wires connected inside the mast near the base to facilitate mast removal? Is there a socket, junction, union, etc - or just excess wire?

What is the best and /or easiest method to access the wires near the base of the mast for inspection / repair - unstep mast or remove interior comp post facia wood?

Thanks

 

[rivettw]

When you tested the power to the light did you ground to the ground wire or ground to the mast at the ground screw? Mine did the same thing on my 37C but the ground was not secure. The mast head light ground was a complete home run wire through the mast to the panel ground. The steaming / deck light was grounded to the mast. Old ground wire connector had corroded. Re grounded the mast. Found this out after buying new steaming / deck light. Just sayin'.
Wally

 

[J Hunter]

My '76 h30 came without masthead light, which I only added recently, but we immediately added the VHF antenna cable in 1976 so I've done two mast wiring jobs on my h30. If the interior is the same, you can take off the teak panel that the sliding door between the salon and the head slides on to access where the mast wiring enters the cabin. Mine doesn't come through the mast step, it exits the mast above deck and has a separate deck penetration, but it sounds like your wiring goes straight down through the mast step. If you can get at the wire there, you can cut it and confirm plus and minus continuity back to the battery there (you'll need to figure out which pair of wires is which- mast head or steaming light- somehow by tracing and tugging inside the cabin or by going up and pulling on the steaming light wires with someone below), then maybe fish a new wire up the mast with the old wire, sending your buddy aloft again to lightly tug it up the mast and terminate it at the steaming light.

 

[malyea]

rivettw -

The old mast ground wire that had corroded - how & where is it connected - mast to keel?

 

[JoeWhite]

Malyea - I realize that you do not have voltage at the light - but this is not due to a short since this would cause the circuit breaker to turn off. Measure continuity from the positive side of lamp to the +ve side of the circuit breaker and same for the ground circuit.

 

[malyea]

I mis-stated - the circuit breaker does pop (I had hoped the cb was faulty but it tested good - just pops in response to the short)

 

[tomgrigsby]

Was the mast recently restepped, and did the problem pop up at the same time? If you know anyone with electronic test equipment, a tektronics 1502 TDR can be used to test wiring. It isn't designed for wire (it's for coax) but I've used them and it would give a good distance measurement to the short. Otherwise you'll have to hand over hand the hot lead. It is shorted to (a) ground but not necessarily to the return wire. There could also be corrosion at the light bulb base or underside of the light base that would pop the breaker. Be sure to clean the bulb socket and underside of the contacts if you can get to them.

 

[malyea]

Just bought the boat few months ago with light inop - prev owner thought it just needed a bulb - didn'y mention any mast unstep/restep history - I suspect the light just quit working however friend Jack suspects pinched wire inside mast base....

I want to try evrything else before I pay some bucks and hours unstepping mast to check that option.

If this helps...When friend Jack went up the mast with a tester (probe with light bulb) I held the circuit breaker closed for 10 to 15 seconds and he found no juice getting to the socket.

Thanks

 

[tomgrigsby]

2 things - 1, no juice at the socket could be a tester problem if it didn't have a valid good ground. 2. Holding the breaker may have produced enough heat to melt the wire insulation at the fault area or in other weak areas. Bummer. Wish I could help with info on wire routing, but my 79 H30 has the wires exiting at the base of the mast and going below through a separate penetration.