Bonding Wire

[tonyiiiafl]

I was in the bilge on my 390CPMY and saw the green bonding wire from the starboard shaft collar broken off, and a wire to the plate with 2 studs also broken from the wire that comes down the hull heading for the stern. Am I correct in that I neeed to reconnect the shaft collar wire back to the main. Line and also one to that plate? The plate has 2 studs, but only had one terminal used for a green bonding wire.

[bud37]

I am not sure what that plate is you are talking about, maybe someone with a 390 CPMY can chime in. Maybe the strut support.

You are correct in thinking the bonding system needs to connect all the underwater metals on your boat together as one, any break in that system will make it ineffective.

Is the broken wiring in an area where people would step while working down there ?

[tonyiiiafl]

Well, I can’t get down there, got pretty stuck last weekend. It is behind the starboard transmission, at the shaft collar. I just got the photo I see what looks like a wire corroded off of the bonding bar. I am wondering if that plate with two studs should also be connected to the bonding system?

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[bud37]

Hopefully the saltwater guys can chime in here.

There definitely needs to be some clean up , that is a fair bit of corrosion on the packing nut/shaft and all those connectors on that small buss bar. The plate in the hull appears to be a white glass backing plate, almost looks like starboard ?

Tony , Do you have a diver, is there a hull anode mounted there ?

I can only suggest what I would do if it were mine.......clean all the corrosion, stuffing box etc , find where those loose wires connect and reconnect them with new ends, check the other side and clean if necessary, then work back thru the boat to see if there are any other red flags/ broken wires or corrosion at the bonding connections.

After all that, check the bonding system as a whole to make sure it is working properly,.....there is a lot of expensive metal underwater on your boat.

[tonyiiiafl]

Totally agree bud. No, no anode there as I have done the bottom painting myself. Probably as you said a backing plate to allow wires to be connected. I have a slim friend coming over to squeeze in there.

[Viper]

Pretty common for the terminal connectors on bonding wires to corrode off in salt water applications. Both the shaft packing gland and the stern tube behind it should be grounded as they are isolated by the hose. As for the plate on the bottom with two bolts, I doubt it's a common connection point. Looks more to me like it might have originally been a backer for a Diver Dream anode or grounding plate on the bottom of the hull, I've seen that before. If that was the case, you may see the heads of carriage bolts on the bottom of the hull if you look close, painted over of course....just a thought. If it was an anode or grounding plate at one time, there should have been a bonding or grounding wire going to it too. Other than that, no idea what the function would be.

Salt water sure does present a challenge with hardware. It would be a lot of work but cleaning the "green death" would go a long way to extending longevity. A cordless drill with a wire brush bit really helps, then just spray the fittings with a clear lacquer or a spray lubricant to keep them from corroding again. Do the same for the wiring bus bars and terminal connectors. After you clean them, you can also spray or paint with liquid electrical tape. Do a few areas evey year and eventually you'll have everything cleaned up and protected.

[tonyiiiafl]

Thanks my friend. There was a wire connected to that plate, but it was the wire from the shaft collar. I retried th wire, and it looks like it was set for a quick disconnect for the connection for servicing?[img][img]

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[Viper]

You want to make sure you correct all the bonding wiring and connections. This keeps all underwater metal at the same electrical potential in the electrolyte immediately around your hull (the water you're in). Failing that will cause through hull hardware not at the same potential (broken bonding wire) to corrode much faster. This can happen quickly in salt water and has been the cause of some sinkings.

If you treat the new connectors after you install them, you won't have to do it again for a long time or ever depending on what you use. Heck even spraying the clean connections with a battery terminal protectant spray will help immensely, which you should have around to use on your battery terminals anyway. When you fasten the wire back to its connecting point, screw the terminal connector in so that the end of the wire going through the connector is facing up. This is the normal way of doing it because it works better mechanically but there are occasions when it works best mounted upside down. Facing the wire end up though allows you easier access to treat/protect the end of the wire at the connector also and prevent corrosion from wicking up the wire internally. Internal corrosion can cause all kinds of hard to trace gremlins because you can't see the condition of the wire under the insulation, and the assumption is that it must be okay because it's covered.....not.

[tonyiiiafl]

Well, today was the day. I had a slim friend (who also had a hard time getting to reach these wires. There was NO way to get down there, so we hung over the floor opening and did our best. I finally removed the battery charger and that gave Mike some room to get down there a bit better. The bus bar shown was all corroded. SO we snipped the wires off, and joined with 8 gauge wire with butt connectors. (I know it was not the right way, but will get me through the season until winter layup) Then we added a new bus bar up higher where it could be reached easier and slowly (4 hours) ran the new wires up to the bus bar and connected together as they were on the original bar. I sprayed the connections with battery terminal corrosion resistant spray, and buttoned it up. I was surprised to see some non tinned wire used, and we had to cut it back until it was clean wire. Hopefully, it will stay (connections were super, and if I wasn’t a tad scared of using a torch even though no gas fumes present To solder thee connections) and work until haul out in October.

[bud37]

That sounds good... To finish up... you really should test for continuity between the bonding system grounding points and your underwater metal/ thru hulls/rudder posts/struts ......may require a decent multi meter and some long test leads and your smaller friend..... . This will show whether you have a complete circuit as you should and whether the anodes can protect all.

I would recommend against soldering connections on a boat.....not because of the torch but the joint itself can be brittle.