Loose ground cable in top

J

jmauld

Well-Known Member
Jun 9, 2020
2,845
Carolina Beach
Boat Info
2010 Sundancer 390
2016 Sea Hunt Ultra 211
Engines
Twin 8.1l of gas guzzling iron
0227B931-A5B3-4C82-8BEE-E837FA1BE425.jpeg
I was looking for a water leak in the top (2010 390DA) and spotted this guy just hanging out. Should it be connected to anything?
 
Looks like it would go on the bolt nearest it. Are those bolts to your radar base? I can ask my radar guru if the base needs to be connected you your grounding system as well as the power ground.
Carpe Diem
 
Carpediem44DB said:
Looks like it would go on the bolt nearest it. Are those bolts to your radar base? I can ask my radar guru if the base needs to be connected you your grounding system as well as the power ground.
Carpe Diem
Click to expand...
The answer may lead to the root cause of the corrosion @ttmott, although there may have been some undue stress involved that we don't know about.
 
techmitch said:
The answer may lead to the root cause of the corrosion @ttmott, although there may have been some undue stress involved that we don't know about.
Click to expand...
Definitely the bonding for whatever is metal (radar) above those bolts. Not only bonding for corrosion but lightning down conductor.
 
The bolts in the radar base are too large for this connector. I pulled this lead out of its hiding spot to get a better picture.
 
Maybe an option your boat doesn't have -- possibly something like satellite TV?
 
jmauld said:
The bolts in the radar base are too large for this connector. I pulled this lead out of its hiding spot to get a better picture.
Click to expand...
Plot thickens - Does it look like it was attached to anything; lug scratched/marred from a lockwasher and nut? Like it was ever installed on anything? @Lazy Daze or possibly there was alternant radar scanners that required the external bonding; I'm always finding wiring unused that was installed for options. I doubt that SR would run that expensive wire up into there and not have a use for it.
My radar has a bonding wire (green) but it runs with the control harness into the unit and bonds to a screw terminal inside.
If nothing else is in that area I would make a lug to fit over that stud, between the jamb nuts and attach that wire to the lug. Can't have enough bonding right?
 
ttmott said:
If nothing else is in that area I would make a lug to fit over that stud, between the jamb nuts and attach that wire to the lug. Can't have enough bonding right?
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Oddly enough, I’m an electrical safety engineer and know more than I should about bonding, etc. but I really know very little about boat wiring. I need to get a grasp on the grounding lugs that are on the electrical equipment and why none of it is utilized on my boat. That third wire that you mention is floating on my radar.

I will check for installation marks the next time I’m at the boat. I somewhat made an assumption that the wire was left off when I had the boat transported to me, but I guess it could’ve never been installed. I can’t figure out why they would need such a large ground wire for any of the equipment up there except for the radar, and possibly lightning. Speaking of that, do any of you use a lightning rod like the sailboaters use when you’re staying on the boat.
 
Remember that there is a significant difference between grounding and bonding even though they all tie together; functionally they are quite different.
From a DC power perspective grounding is required to provide current from the batteries and thus allow electrical devices to operate. Bonding on the other hand does two important things - first to bond the boat's anode (zinc) to all of the metallic components and defer the galvanic current from the boat's equipment to those anodes. The anodes are corroding rather than your boat's equipment. Secondly, the bonding networks all of the boats's metals together and provides a path to water for things like lightning strikes and other electrical shunts like to hand railing, and metal superstructure.
The DC Ground system, Bonding system, AC ground system, and AC neutral system (when on generator) are all tied together for two reasons - first to ensure a safe electrical path to water and not through someone and second to prevent ground loop interference in the boat's equipment.

After taking a severe lightning strike a couple of years ago and the carnage it caused on the boat, I've learned a lot. I also learned really how little most know about these electrical systems especially shockingly (pun) how little marine "electricians" know.
 
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A simple illustration - First everything conductive has natural electrical potential in the environment - it is essentially a battery when two dissimilar conductors are in contact (like aluminum in contact with stainless steel and that salt water electrolyte between them). Especially in a salt water environment - all the chemistry is there. Now let's say you are operating your VHF radio and it is requiring 12 volts DC and demands 1 ampere of current so those electrons flow from the negative terminal on the battery to the positive terminal on the battery. The battery is saying I'm giving you this many electrons consequently I'll only receive that exact many electrons. But wait, there are all these natural batteries also providing additional electrons; what to do with those? So, the system is seeing, let's say, 12.06 volts and consequently there is 0.06 volts of current that is escaping through typically the underwater metallic structures. As electrons pass through to the water they take ions with them which is the metal itself. Not good right? Ya can't stop it from happening so what to do? Metals are classified in nobility - Metals high in the noble classification are very resistant to galvanic corrosion like gold and stainless steel but others on the bottom of the chart readily give up their ions like aluminum, magnesium, and zinc. So, we put the sacrificial less noble anode materials in the bonding network to pass that low level (0.06 volts) of current and allow them to corrode rather than the important things on the boat.
 
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If it makes you feel any better i found a similar wire tucked into the arch of our 420 DB. Assumed it was for something that we weren't optioned for. But a closer look shows it references the mast light. If you pull that shield back it may be labeled. Sea Ray did a great job labeling all cabling.
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Very good description of grounding vs bonding in a boat
ttmott said:
Remember that there is a significant difference between grounding and bonding even though they all tie together; functionally they are quite different.
From a DC power perspective grounding is required to return current to the batteries and thus allow electrical devices to operate. Bonding on the other hand does two important things - first to bond the boat's anode (zinc) to all of the metallic components and defer the galvanic current from the boat's equipment to those anodes. The anodes are corroding rather than your boat's equipment. Secondly, the bonding networks all of the boats's metals together and provides a path to water for things like lightning strikes and other electrical shunts like to hand railing, and metal superstructure.
The DC Ground system, Bonding system, AC ground system, and AC neutral system (when on generator) are all tied together for two reasons - first to ensure a safe electrical path to water and not through someone and second to prevent ground loop interference in the boat's equipment.

After taking a severe lightning strike a couple of years ago and the carnage it caused on the boat, I've learned a lot. I also learned really how little most know about these electrical systems especially shockingly (pun) how little marine "electricians" know.
Click to expand...
 
I was working under the helm the other day and noticed severe corrosion on the A/C water pan. I found tucked behind the unit, a bonding wire that had been broken off and not repaired. Another winter project now is to fabricate a new pan. I’ll build one out of SS. I since looked at all of the other A/C pans and they have little or no corrosion as their bonding wires are intact. IT MAKES A DIFFERENCE!!!
Thanks for the reminder lesson on marine electricals Tom
Carpe Diem
 
That wire is labeled light mast. But it won’t actually reach the bolts on the mast. I’ll figure something out to get it connected.


There’s no reason to not ground the radar right? If so I’ll just make a stud for it.
 
jmauld said:
That wire is labeled light mast. But it won’t actually reach the bolts on the mast. I’ll figure something out to get it connected.


There’s no reason to not ground the radar right? If so I’ll just make a stud for it.
Click to expand...
You can also daisy chain things - fabricate a metal tab and install on one of the radar bolts and connect that conductor then route a new conductor to the light mast from that metal tab.
 
That’s what I had in mind. Stainless steel is okay for this application?
 
Can you just drill out the hole in the connector a bit to fit over the radar stud?
 
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