3 wire power cable

[torcano]

I removed an old raymarine radar unit from my boat and since then other electrical things on my boat (cabin lights, electric wench, stereo) are no longer working. The breakers all seem to be OK.The power cord from the Raymaine was tied into a positive, negative and third wire (green on my boat) I installed a new Garmin GPS unit using only the postive and negative wires. The GPS works but other electricals now do not work. I did not re-connect the green wire to anything. Any ideas what to do? Should I re-connect the green wire into the new Garmin power cord? There are a batch of colored wires that are available but I do not have a clue what they are for.

 

[Silvertip]

Re: 3 wire power cable

What boat you are working on, model number of what you removed, model number of what you installed, a detailed description of what doesn't work and what does work just might help us rather than "guessing". And other than checking breakers and fuses, what have you checked.

 

[torcano]

Re: 3 wire power cable

The boat is a 2002 280 Searay Sundancer. Removed RayMarine S172 radar. Installed Garmin 541S GPSMap. So far I see that the stereo, cabin lights and elecrtric winch do not work. The dash light on the winch does however light up. I have only checked fuses and breakers.

 

[Silvertip]

Re: 3 wire power cable

That green wire may have had nothing to do with the original unit. Green is typically ground or a "bonding" wire so ground it and see what happens. Don't connect that to the ground wire on any other accessory. Connect it to the negative terminal of the battery or to a negative buss, wherever you find one. The items that don't work should have had nothing to do with the removal and installation process so that leaves the green wire as the suspect.

 

[torcano]

Re: 3 wire power cable

Thanks, I will give it a try. Hopefully, my next post will say thank you for figuring out the problem

 

[NYBo]

Re: 3 wire power cable

Removing one unit and replacing it with another shouldn't cause anything else to stop working. Perhaps you pulled something loose in the process?

 

[Grandad]

Re: 3 wire power cable

I suspect the problem is a bad negative connection at a common negative busbar. Assuming that the various components you mentioned each have their own separate positive circuits, the common denominator is the negative connection point for all. This would also explain why the winch switch still lights up. The light in the switch likely uses a local dashboard connection to ground. I would expect a poor connection in a conductor between the busbar and the battery. - Grandad

 

[torcano]

Re: 3 wire power cable

I tried running the green wire directly to the negative terminal on the battery. My cabin lights came on but no winch. Surpringsly, when I disconnected the bonding wire the cabin lights still worked. However, when I tried to lower the anchor all I heard was a clicking sound which appeared to come from the engine compartment. Any idea what the clicking sound could be? I just had my marine change the manifolds and risers. Could they have disconected something in the engine compartment to cause the problem? Pehaps my removing the radar had nothing to do with this problem.

 

[Silvertip]

Re: 3 wire power cable

Ahhhh -- yes, the problem you have now could very easily have been caused by careless work at the service facility.

 

[Grandad]

Re: 3 wire power cable

However, when I tried to lower the anchor all I heard was a clicking sound which appeared to come from the engine compartment. Any idea what the clicking sound could be?

Most times, the clicking sound is from a relay or solenoid that normally does the "heavy lifting" for larger loads that can't be switched directly by a small dashboard switch. The relay coil is getting the message as you push the switch, but because the voltage is low in the circuit it is trying to control, nothing further is happening. The low voltage condition in the heavy load circuit can be caused by a poor connection at any point in the positive or negative circuit paths to the load. Because you're experiencing a problem with other devices, a poor connection in the negative is most likely the problem. - Grandad

 

[torcano]

Re: 3 wire power cable

Thanks. The negative battery terminals seem tight and free of any corrosion. Any suggestions as to how to start looking for the source of the bad connection?

 

[Grandad]

Re: 3 wire power cable

Thanks. The negative battery terminals seem tight and free of any corrosion. Any suggestions as to how to start looking for the source of the bad connection?

Assuming a low voltage condition that shows up primarily on a heavy load such as your winch:
1. Is the battery in good condition and charged fully?
2. Since you have confirmed that the battery terminals are secure, follow the cables to the next distribution point and confirm the condition there. Inspect both the terminal connection to the busbar and the terminal connection to the wire or cable. They must not only be tight, but show no evidence of corrosion. If any corrosion, clean, repair or replace the terminal. Add a dielectric grease to prevent further corrosion. Make improvements to one wire at a time, then check for performance if you want to know where something actually has failed and been corrected.
3. When you reach a point in the distribution such as at the fuse panel, branch off to the winch circuit to find the clicking relay, then confirm those terminations. Follow the entire winch circuit loop back to the negative connection to the distribution system. Make sure that you are physically following the same cable. Sometimes you'll find someone has added a terminal bar in an unlikely and poorly maintained location.

TIP - Following the electrical path with a voltmeter isn't likely to help in this circumstance. A voltmeter puts almost no current load on a test point. It will likely read full voltage beyond a corroded connection, unless there is an actual break in the conductor.
- Grandad

 

[torcano]

Re: 3 wire power cable

Thanks. I'll start exploring over the next few days and let you know what I find.

 

[torcano]

Re: 3 wire power cable

Grandad, you were right about the negative grouinding wire. It looks like the negative cable going to the windlass motor snapped off. I am not sure how to reconnect it but I am sure I will have to take out the motor which is in the anchor locker to fully investigate it. Any experience with removing a Lofrans-Marlin winch? It looks like there are screws that go through the deck and hold the motor in place.

 

[Grandad]

Re: 3 wire power cable

Any experience with removing a Lofrans-Marlin winch? It looks like there are screws that go through the deck and hold the motor in place.

Sorry torcano, I have no direct experience with yacht winches. I'm sure someone on this site may have some more experience with winches and may be able to help if you get stuck. I have considerable electrical experience only. As it happens however, I did help remove a stator winding from a mooring winch on a Great Lakes cargo ship while in transit back in the early 80's. Totally different. Was a fun trip. - Grandad

 

[torcano]

Re: 3 wire power cable

Thanks anyway. You have been very helpful.