J/30 Class Association Forums J/30 Forum The Boat, Sails and Equipment Electrical ground

In Iowa we have to much water, so Phantom still is in my backyard. I'm contining to work on the boats electrical system. Behind the electrial control panel is a ground relay attached to the hull. It's gound to the engine, which is ground to the battery. The problem I'm having is none of the circuits work with out wiring directly to the battery. For example when I installed the bilge pump, I could not get it to run until I ran a wire directly from the pump to the negative terminal on the battery. Is the ground wire that runs through the bilge tied in to the system? How about the shore power? I use to have cabin lights but they are no longer functional.

John - the DC return at the DC Switch panel should be a direct run back to the battery negative terminal. I suspect you have a bad crimp connection, lug, or connection, as it is uncommon for the wire to break unless it is right by a connection. If you have had other issues, you may see burnt insulation, but you would see signs of that and would have smelled it. Try checking the connections at both ends first with a meter.

Agreed. The engine, keel bolts, and standing rigging/mast should be bonded together for corrosion protection and to provide a path to ground in case of a lightning strike. They should never be used intentionally to carry current.

The electrical system on these boats is aging. I had an overhaul done a few years back. Brand new power and negative from the battery switch to the panel. Also, the panel itself isn't that well built. There is no hot bus bar; rather, a whole mess of crimped on terminals on short jumpers daisy chains one circuit to the next. The result: A lot of resistance and voltage drop! Since I wanted to keep the original panel, I had a hot bus installed, which connects to the battery switch through the main fuse (located near the battery.) Then an individual hot wire runs from the bus to each panel switch. The voltage drop at the panel pretty much went away.

Shore power presents its own concerns and dangers. I suggest getting a good book on marine electronics.

My 1979 has all cabin lights tied to a single power switch. With 3 lights on at the same time, the switch is getting pretty hot. I am thinking about breaking the lights into three zones, front, mid and main cabin to see if this helps. Anyone tried this in the past?

David, I recall my switches were getting hot, too. The voltage drop was so bad that my instruments would reset themselves, depending on how many lights were on.

If your boat is anything like mine, I don't think breaking the lights into three zones will fix all the problems. In my case, this was related to the panel design as it aged. I recall one positive wire from the battery, which is connected to one fuse via a crimped on terminal connection, which is connected to the next fuse via a short jumper with crimped terminal connections, which is connected to the next the same way, etc. The result: current to some fuses has to go through, say, 20 jumper wires and 40 terminal connections first! This works fine when the boat is new from the factory, but after 25 years, the terminals corrode and more resistance develops. So the panel itself becomes a big resistive heating element. ;-)

My $0.02: Invest in a good, accurate voltmeter. (I've got a very nice Fluke meter that I love.) Turn on all the lights. Measure the voltage difference between + and - at the battery. Then work outwards, looking for voltage drops. You should be able to isolate how much of this is due to the wire run between the battery and the panel, internal resistance within the panel, and resistance along each circuit branch to the light.

In my case, I needed a new positive and negative wire to the panel, and a better distribution scheme at the panel. The positive from the battery fed a bus, which has one positive wire leaving it per circuit and going to each panel fuse.

Good luck!

Ryan
Tesara, #337

Ryan is spot on with his suggestion on measuring the voltage drop. I burnt the main fuse socket by the battery switch last year due to oxidized terminals providing a high resistance path - it became a heater element under load. Additionally it appears that when the boats were built they did not used tinned wire. If you strip back the insulation, instead of bright shiny copper, you'll see black oxidized and in some cased green verdigris where salt entered on all the conductors throughout the boat.

Here are some links to J/30 wire harness schematics that were on the old J/30 web site:

"The wiring schematic from hull #406 is now available online. You can download page 1 , page 2 , or page 3 . For those of us with earlier hull numbers it provides a reference about the major elements of the electrical system, even if all the details aren't the same."

[This message has been edited by Rhapsody #348 (edited 06-27-2008).]