electrical circuit problems

petergumbrell · #1 (**permalink**) 09-30-2007

I have just taken possession of a 1984 Jeanneau Fantasia. I have discovered that a few of the electrical circuits do not work. For example, the VHF radio did not work and I tried connecting another one but this did not work either. I also tried the connections for the older GPS that was there and my tester did not find any current on that circuit. When I pulled the breaker panel off and took a look, I did not see any obvious signs of problems. There were no wires that were not connected or that looked corroded. Everything looks good there.

I'm at a loss as to how to proceed. The circuits that don't appear to be working are from different parts of the breaker panel. Should I replace the breakers - is that likely to be part of the problem? I noticed that the wiring inside the panel wasn't as simple as I hoped it would be - i.e. one red and one black for each breaker, so I'm not sure to to proceed to rewire those circuits.

If someone could direct me to a book or a web-site, or give me some tips as to what to do next, I would be grateful.

Many thanks,
Peter

Freesail99 · #2 (**permalink**) 09-30-2007

Did you check for an inline fuse ?

denby · #3 (**permalink**) 09-30-2007

I would test the breakers before replacing them. Some times on low amp circuits there is a fuse in the positive line between the breaker and the device. Check for fuse and check the connections to make sure they are good.

denby · #4 (**permalink**) 09-30-2007

How good are you with electrical circuits?

Dennis

sailingdog · #5 (**permalink**) 09-30-2007

Did you check the power connections of the VHF and the GPS for voltage? If so, what was the voltage? If the voltage was low or it didn't give a reading... then the wiring either is non-marine grade and has corroded or there's a break in the wiring. BTW, if the wiring has a splice in it, the end you are looking at might very well have no corrosion, but that doesn't mean the whole length isn't corroded.

I'd also recommend looking for in-line fuses and check the breakers to see if they're still good. Checking the breakers is pretty simple. Put the ohmmeter across the contacts and throw the breaker... if you get a continuity or near zero ohm reading, the circuit breaker is probably still good.

BTW, checking for current is usually less useful as a basic trouble shooting tool than checking resistance and voltage. Checking current only makes sense if you have a contiguous circuit that has voltage over it.. there's no point in checking current if there is a break in the circuit or no voltage to it.

As for books... Nigel Calder's Boatowner's Mechanical and Electrical Manual is a good one to start with.

Quote:

Originally Posted by petergumbrell

I have just taken possession of a 1984 Jeanneau Fantasia. I have discovered that a few of the electrical circuits do not work. For example, the VHF radio did not work and I tried connecting another one but this did not work either. I also tried the connections for the older GPS that was there and my tester did not find any current on that circuit. When I pulled the breaker panel off and took a look, I did not see any obvious signs of problems. There were no wires that were not connected or that looked corroded. Everything looks good there.

I'm at a loss as to how to proceed. The circuits that don't appear to be working are from different parts of the breaker panel. Should I replace the breakers - is that likely to be part of the problem? I noticed that the wiring inside the panel wasn't as simple as I hoped it would be - i.e. one red and one black for each breaker, so I'm not sure to to proceed to rewire those circuits.

If someone could direct me to a book or a web-site, or give me some tips as to what to do next, I would be grateful.

Many thanks,
Peter

petergumbrell · #6 (**permalink**) 10-01-2007

Quote:

Originally Posted by denby

How good are you with electrical circuits?

Dennis

I've only had experience with electrical wiring at home, but I imagine a boat is quite different.
Peter

sailingdog · #7 (**permalink**) 10-01-2007

Peter-

If you can do 120 VAC wiring, 12 VDC wiring isn't going to be much different. The major difference is that instead of using ROMEX solid wire, you need to use tinned, marine-grade wiring, and instead of wire nuts, you use crimp connectors.

I highly recommend you get a good ratcheting crimper as well as a good wire stripper. Ancor makes a good set... but buy them at Home Depot, rather than West Marine, as they'll probably be a good deal cheaper there.

jrd22 · #8 (**permalink**) 10-01-2007

Keep it simple, start at the hot side of the breaker in question and determine if you have 12+ volts there, then check across the breaker and make sure you have voltage with the breaker closed. If not, then the breaker is probably bad. If you do have voltage follow it to wherever you lose it, and that will be where the problem is. I would check continuity from the breaker labeled for the Vhf and the power wire at the Vhf, could be that the power wire for the Vhf has been moved to another breaker, you never know what someone has done in the past. It can get a little complicated but always start where you have the correct voltage and then track down where you lose it. You will definitely need some kind of volt/ohmmeter to get started, doesn't need to be an expensive professional one, but get something decent. I second SD's book rec. Good luck, John