Electrical issues, ground/neutrals and bonding

I'm going through hull zincs every month. Had new ones installed on November 22nd. Diver on January 13th says port hull zinc at or below 50% and starboard one at 75%. Had a good electrician out to inspect everything. Certified in Corrosion, etc. Well known "anal" guy. In fact the first thing he said when he got on the boat was "Did (guy who refered me to him) tell you how anal I am?" I said yes he did. Anyway, he went through the boat, anode overboard, checked bonding system. Electricity, marine or dirt, it NOT my forte to say the least. Trying to learn but from what I remember:

1. On the bonding, got .750 on the through hulls with .950 on the shaft. Said that was because I had zincs on the shifts. There was one through hull that was a bad reading but I don't remember what it was or the reading. I know I should have been writing all of this down but didn't.

2. Checked out the system in general and said I needed to have the ground/neutrals separated. I believe because power was bleeding back off the boat? He also said I needed galvanic isolators installed. Also said that my neighbors really appreciated having me here. I assume because they, or one of them, is using my zincs so to speak.

3. A new power cord as there was bleed through on one of them. Water intrusion or short somewhere. Power cords are fairly old.

Anyway, he quoted me $3K on the separating neutrals and grounds and $8K on redoing the bonding system. I'm going to have a second guy come out and do the same. Will take a pen or pencil with me this time In the mean time, does any of what I said make sense and do prices seem about what you guys would deem appropriate? I know I am REALLY vague on this but any comments appreciated even if they are along the lines of "Dude, go back and get specifics because we can't tell you a things from all of your nonsense"!!!

Adding a galvanic isolator is simple if you can access the ground wire between the inlet and the electrical panel.

If you have 2 shore power inlets, the neutrals should not be comingled. With the new NEC that requires GFIs on docks, if your neutrals are comingled your boat will trip the GFI on the dock. My boat has 2 30 amp inlets and all the neutrals were on one bus bar. It took two of us a couple of days to split the neutrals and also replace the main electrical panel.

Redoing the bonding system is going to be a lot of grunt work just getting to everything and running the wire. Not very technical although. Just a lot of attention to detail.

Of the 3 tasks the only technically difficult one is seperating the neutrals. Doing the other 2 if you are good at DIY should not be above your ability. Maybe hire the electrician to oversee you doing the bonding if you want to save some money. Installing a galvanic isolator is very easy, just break the green inlet wires, put connectors on the wires and attach the connectors to the isolator.

Good luck.

Thanks Como. I have a 50amp connection on the bow and 30amp on the stern. I have not investigated where I could place the isolators but the stern of the GB 42' doesn't seem to be very friendly due to the 3 water tanks that run across the transom. I know that the isolators are supposed to be as close as possible to the connection. Not sure where the wiring runs after it leaves the connection but putting in a GI would seem to be forced to at least 6-10' away. Not sure though. Electrician told me exactly what you said. Bonding is grunt, dirty nasty work but not high tech. I could help if I wanted. I was just surprised at the $8K cost. On the grounds and neutrals...I am at a loss as I don't even know where they are much less how to deal with them. I'm looking at some learning course for marine electric as I really need to at least understand the basics. Not very intuitive to me! I get lost when I read that grounds and neutrals MUST be separated....EXCEPT....they are joined at one point. Huh? I believe ground goes back to ground...earth...water. Neutrals go back to the battery. I think. Maybe. If you are supposed to cross them at one point why the big deal when they are crossed elsewhere? As you can see....no real knowledge. I will keep reading.

Yes what you said makes sense. I agree with comodave’s comments as well. You have become the the sacrificial anode for the entire marina. Your neighbors are all bragging about how they haven’t needed to change their zincs all year. LOL.

As comodave said none of the tasks are particularly challenging technically but it’s hard to estimate how much grunt time will be needed. I once separated grounds and neutrals on a boat, took me 10 minutes to separate the first 25 and 3 days to separate the last one.

8k for a new bonding system? Sounds like a lot but I don’t know what is being specked out.

AC neutrals do NOT go back to the battery....neg DC goes back to all batteries and at one point joins bonding system and AC grounds.....

Keep reading....

Grounds and neutrals are combined at the source of the power. This means if your power comes from shore then they are combined at the shore source, not on your boat. When you are on generator they are combined at the generator. That’s why they are sometimes separated and sometimes not.

A good marine inverter automatically combines and separates the ground and neutral.

I actually knew that it is neg DC that goes back to battery but I will still continue reading! Maybe throw in a book about how to communicate clearly.

Electician told me that the firs task is the neutral/grounds. Bonding could come later. He seemed like he didn't think it a big issue. Basically my ribbon system is just tired and old after 30 years, possibly connection/conductivity issues.

I do not understand how I am the community zinc. Because I am allowing ... never mind. I won't even try!

tiltrider1 said:

Grounds and neutrals are combined at the source of the power. This means if your power comes from shore then they are combined at the shore source, not on your boat. When you are on generator they are combined at the generator. That’s why they are sometimes separated and sometimes not.

A good marine inverter automatically combines and separates the ground and neutral.

Click to expand...

I have an inverter installed.

Each boat is different as far as access and $$ if you want to redo your grounding systems. Last fall mine was redone for about 2K by a real pro. But, I was not going through zincs like you.

For the money they quoted you suggest an isolation transformer or two be evaluated. Victron has some new design ITs out that may be worth a look. Your marine electrician should immediately know about Victron's offerings.

Also, suggest a redesign of your grounding system must be done where there is a new design GFIC 30 ma pedestal or a test plug in arrangement. Without this your efforts to redo the grounding system may be for naught. Eliminating the 30 ma trip is an ultimate goal IMHO. A proper (there are indeed wrong ways) redo of the bonding system should fix this. Does your vessel presently trip a 30 ma GFIC dock pedestal?

sunchaser said:

Each boat is different as far as access and $$ if you want to redo your grounding systems. Last fall mine was redone for about 2K by a real pro. But, I was not going through zincs like you.

For the money they quoted you suggest an isolation transformer or two be evaluated. Victron has some new design ITs out that may be worth a look. Your marine electrician should immediately know about Victron's offerings.

Also, suggest a redesign of your grounding system must be done where there is a new design GFIC 30 ma pedestal or a test plug in arrangement. Without this your efforts to redo the grounding system may be for naught. Eliminating the 30 ma trip is an ultimate goal IMHO. A proper (there are indeed wrong ways) redo of the bonding system should fix this. Does your vessel presently trip a 30 ma GFIC dock pedestal?

Click to expand...

In the slip I am always on 50amp. Not tripping anything. The only time I hooked up to 30amp was when I was hauled for a bottom job. No tripping then.

Form what you have said, your guy seems knowledgeable and honest in his assessment and description of the work. So that's a good start. His work may be expensive, but if he knows what he's going and fixes it correctly the first time around, it may well be money well spent. The alternative always seems to be paying two idiots twice to not fix the problem.

Thanks. I don't like a lack of basic knowledge of things and am ok with spending some money to get it. What threw me off was that I called the guy to a) fix a bilge pump (pump works fine but not getting power to it for some reason. Tried to trace the wiring back as far as I could but it goes into the panel and ...I got lost from there). and b) take a look at whatever is eating my zincs. We never got to the bilge pump and I wasn't expected $3K and $8K for anything so it all came as a big surprise. Sort of floored by that a little bit. But...its a boat and that what happens. I want to have a second guy some and do the same as well as fix my bilge pump. this time I will pay more attention to the exacts on the bonding and the grounds/neutrals. I have to solve the issue so will most likely call the original guy back to do the gorunds/neutrals. I'm not sure if the $3K included the isolators or not. I don't think it does.

Also, on the zincs, the bonding system has nothing to do with why my zincs are getting eaten correct?

firstbase said:

Also, on the zincs, the bonding system has nothing to do with why my zincs are getting eaten correct?

Click to expand...

Depending on what he's including in the "bonding system", it probably does. But it sounds like you are unclear what each piece of work includes, so I think it would be good to get that clarified.

I missed the part about your bilge pump, and that now makes me wonder about the guy. Also the lack of clarity around what each piece of work involves and what might be extra.

Lack of clarity is my first name when it comes to electrical. A little better on land...on land it's my middle name. This particular guy works on huge boats, restorations, mega yachts. I sort of got the feeling that looking at my bilge pump was a little beneath him. Plus I think he got pissed off at me when one of my bilge flooring grates, cut too narrow by the PO, slipped off one side and when it went down to the bilge floor caused him to scrape a knee. I have since fixed that issue. Sure wish there was an online class on marine electrical. I have the known books. Just get lost pretty quickly. The other problem I have is that tracing wires and systems in my boat is just a pain and hard to do. Big news to everyone in here right??

firstbase said:

In the slip I am always on 50amp. Not tripping anything. The only time I hooked up to 30amp was when I was hauled for a bottom job. No tripping then.

Click to expand...

Not 30 amp. 30 milliamp. 30ma is the stray current trip point for the newer GFIC dock pedestals. A decent marine electrician can fill you in on this new dock code design and also tell you how he would test on an ongoing basis as new grounding system is installed to insure a re-do of the bonding system would eliminate that issue.

If your neutrals are comingled, it will trip the dock GFI. The probable reason you are not tripping the dock GFI now is that most docks do not have GFIs yet. The change to dock GFIs came from a new NEC in 2011. Docks are just now (within the last year or two) converting to GFIs. As time goes by, more and more docks will have GFIs so getting the problem fixed, even if you are not experiencing a problem at your dock, is very important unless you plan on never plugging into another dock. If a marina does any substantial electrical work they will be required to upgrade to GFIs. Florida is a prime example due to the hurricane damage, almost any dock that had damage will most likely convert to GFIs.

I wonder if the bad bilge pump and the zincs problem are tied together. If the bilge pump itself has water in the casing or the wire insulation is cracked and submerged, that could cause some stray current corrosion.

Take a look at Jims tests:
https://gilwellbear.wordpress.com/c...ics/boat-ac-topics/ac-safety-tests-for-boats/

Certainly not for everyone.

A docked boat can sink quite a bit of ground current thru the u/w metal parts from the dock electrical ground. You don't even need the breaker turned on.
I would measure the ground current somewhere in the line; down to mA.
If there is much of that, then the isolator has merit.

If the ground current is high ONLY when the L and N are breakered on, then that points to some leakage from something that has power. there will be a GFCI trip soon (if a modern dock) or there will be zincs lost.

The DC story would go differently. There, some low level fault from something like a bilge pump from +12V through bilge salt water could cause some bad things to happen, especially if the bonding circuit was not well connected to DC-.

8000$ to redo your bonding??? What is the size of your boat?

L

Homemade galvanic isolator:




Cost, about 20$, let say 25 with the box, switch and test led.

L

I don't post here often because I got sick of the arguments and I almost never post on electrical issues this complex because there is simply no way to educate some one on this without at least a week long seminar. I am commenting soley because this is such a serious issue.

I'll say two things.

1. Your surveyor is exactly correct on all aspects.

2. I'm surprised he did not make a bigger deal of the ground/neutral issue as it can be lethal.

You pays your money and takes your chances.

Lou, the boat is a GB 42'. I appreciate everybody's comments and putting up with my lack of knowledge. I intend to get all three items sorted out, bilge pump, ground/neutrals and bonding. Just trying to get a little education along the way.

Boatpoker, he did tell me to sideline the bonding for now and get the grounds/neutrals sorted first as that is more important. That is the plan in a couple of weeks when I have the time to be there for a day. Also, I have no GFCI on the boat. That's not good so addressing that as well as at the same time.

Our plan is to cruise for a couple of years when I retire, 2019 most likely, so am getting everything up to par now. Both equipment and knowledge.

High Wire said:

I wonder if the bad bilge pump and the zincs problem are tied together. If the bilge pump itself has water in the casing or the wire insulation is cracked and submerged, that could cause some stray current corrosion.

Take a look at Jims tests:
https://gilwellbear.wordpress.com/c...ics/boat-ac-topics/ac-safety-tests-for-boats/

Certainly not for everyone.

Click to expand...

This is very likely. Wasting zincs are a DC leakage issue, not an AC leakage issue. A bilge pump (DC powered) or float switch sitting in water is a very common source of DC leakage current. So you have multiple issues to work through, some actively causing problems, and some problems waiting to happen.

That is correct about anodes and DC current. We had a boat that had 46 V AC leaking into the bilge water. It didn’t use anodes any quicker than normal. When I first found out about it was when I touched the water in the bilge while leaning on an engine. Checked it with a meter and found the 46 Vs. PO had reversed the hot and neutrals when he replaced the shore power inlet. He also used 14 gauge wire for the 30 amp inlet. They had been heated up enough to turn the white insulation brown. Replaced the inlet wire with 10 gauge and put the neutral and hot leads in the proper order and voltage in bilge was gone.

I agree that maybe your bilge pump could be the source of the anodes wasting prematurely. Also the neutral AC wireing is a real safety issue.

Comment 21
You really do get what you pay for. Your DIY galvanic isolator could be downright dangerous if the safety ground ever had to pass phase to ground fault current. If you did not include a capacitor parallel to the diode bridge, than any AC will cause the diodes to conduct and galvanic isolation will be lost.

There are reasons, and not because "they" are ripping you off, that a quality, Standards compliant galvanic isolator costs about $300.

CharlieJ said:

Comment 21
You really do get what you pay for. Your DIY galvanic isolator could be downright dangerous if the safety ground ever had to pass phase to ground fault current. If you did not include a capacitor parallel to the diode bridge, than any AC will cause the diodes to conduct and galvanic isolation will be lost.

There are reasons, and not because "they" are ripping you off, that a quality, Standards compliant galvanic isolator costs about $300.

Click to expand...

Can you elaborate on why it could be dangerous (meaning more dangerous than one you would buy in store)?

L

Has it been tested to pass full fault current? What is its surge capacity? Are the components properly rated? What is the heat transfer capability of the box should the safety ground start passing less than full fault current? Etc., etc., etc.

ABYC A-28 requires a long list of qualification tests verified by a third party.

Its your boat.

What may make you think the point you mention were not addressed? You can believe me (or not) that this one passed in the hands of a very competent person to ensure it won't cause any issue.
Don't worry, the diodes I used are rated way over what would ever flow through my boat. It is not my intend to put anybody at risk in or out of my boat.

L

homemade galvanic isolators are not all that complicated but should meet the simple ABYC requirements.

most boating stuff is not rocket science, but does need to meet some safety issues landlubbers arent always familuar with.