Need some quick advice, I'm 10 days away from launching my boat and need to figure out the grounding. I have installed an r&d flexible coupling which breaks the continuity of electricity to sea water. R&D sells a silver impregnated rubber strip that one rolls up and installs inside the flexible coupling to re-establish the connection. I can do that or simply install a sintered grounding plate.
Which would be a better solution?
Seems to me you would want a bonded shaft. Ive seen a copper bushing mounted on spring steel that rides on the shaft and then has a grounding wire that goes to the block or the bonding system. That said, your solution between the coupling seems simpler.
When we had a prop saver plastic thing in place I ran a short wire jumper from a bolt on one side to a corresponding bolt on the other. It was simple and seemed to work.
Guys : I've had a flexible coupling for over 25 years and have not bonded it. Just use one shaft Zn and have never had a problem!!
A thought
Quote from: Ron Hill on February 18, 2021, 02:12:02 PM
Guys : I've had a flexible coupling for over 25 years and have not bonded it. Just use one shaft Zn and have never had a problem!!
A thought
Ron, what do you use to ground your boat? How's the negative dc and green ac wire grounded to the sea?
Right or wrong, I had viewed the prop shaft like a grounding rod driven into the earth to provide a ground for your house electrical system. On our boats, the system negative cable from the onboard electrical system connects to the starter/engine/transmission which in turn connects to the propeller shaft (grounding rod) that's in the water (earth). The engine/transmission are on isolator mounts. If a flex coupling isolates the connection from the drivetrain to the propeller shaft, how is connecting to the starter/engine/transmission grounding the boats electrical system? Maybe the bolts fastening the transmission flange to the propeller shaft flange provides the electrical connection to provide the ground?
I'm looking forward to hearing from the experts.
Logo
I have the same issue, deliberating between sintered bronze plate, wire connecting two bolts in coupler and "stuffing" R&B sels . I found this..
https://www.marineoutfitters.ca/index.cfm?category=10002|11172&product=60463436&code=031669200357.
I'm not electrician either, but how about led keel via bolts as ground ? After all it is huge chunk of metal in water.
Quote
The return electrical path
a lighting strike to "earth" via the shaft
Both the DC and AC systems are bonded to earth thru the AC ground/green shore power conductor (if your boat is ABYC compliant) or unless you have a galvanic isolator installed.
You can't possibly provide enough current carrying capacity for a lightning strike traveling down the mast to jumper to the prop shaft, and if it did along the way it may blow out the stuffing box/shaft log (strikes have blown out thru hulls.)
A faired and painted lead keel is a poor conductor to earth, but the bolts should ideally be bonded.
A bonded shaft is better than a non-bonded shaft (the more continuity in bonding and more sacrificial anode locations the better -- but everything is a trade-off.
Your Hx is similar to the shaft-- it's best to bond it, but if not and it's isolated -- the anode therein protects the "local battery" created by the different metals that are immersed in the electrolyte.
Maybe an expert(s) out there could explain the "necessity" for a bonded shaft? Wouldn't just having a shaft zinc and a HX zinc solve most issues that may be caused by a flexible shaft to engine coupler?
Jon
Re: grounding rod.
Is your AC and DC separated? i.e., not bonded? Or bonded and you have a GI installed?
No GI, and AC not connected to 12vdc negative buss if that's what you're asking. Main AC breaker is an ELCI I installed as part of my electrical upgrade in 2016.
Is a sea water ground necessary (per code or otherwise) for the AC and/or DC electrical system?
You guys really lose me sometimes.
If interested to catch up...
ELCI (Equipment Leakage Circuit Interrupter) Shore power breaker:
https://waggonerguide.com/elci-protected-shore-power/
GI (Galvanic Isolator):
https://shop.pkys.com/What-is-a-galvanic-isolator-and-why-should-my-shore-power-system-have-one_b_112.html#:~:text=A%20galvanic%20isolator%20is%20a,act%20as%20a%20giant%20battery.
Guys : I'm not too sure exactly why you need or what a bonded drive shaft really does for a boat ?? Never had a problem without one???
A thought
Jon
Ok. You're aware that's not abyc compliant? The E-11 requires bonding the DC neg to the AC ground, whether or not there's an ELCI.
-k
This is how my grounds/negative wires look behind my panel. I have a green wire to my engine block. However my, I do have a Vetus Bullfex flexible coupler with no "cross/bridge/strap" to the shaft. Don't know if this is an issue or not?
Quote from: Noah on February 21, 2021, 06:21:56 PM
behind my panel.
green wire to my engine block.
Your DC negs are bonded to the AC ground (compliant.)
Have no clue why a bond wire would be run to the engine block when it's already bonded by:
Neg btty cable on engine > btty terminal > wire to bus behind the panel. Belt/suspenders maybe?
Just a "fyi observation"...
All the yellow terminals are non-compliant and were also crimped using the wrong tool (which in itself is non-compliant (both those are not a 1990-state-of-the-art thing, they're a typical CTY crack technician thing.)) That could be a rainy day project! The pic of the disconnected terminal evidences the result of using the wrong tool and that the resulting crimps/connections/continuities surely aren't competent (as below; courtesy Mainsail.)
All of those yellow crimps were original Catalina 34 wiring and were not redone when I replaced my AC/DC distribution panel with a BlueSea 360 panel and did other major electrical upgrades.. Someday, maybe I will re-crimp those...but, it is a very tight unfriendly space to work in so it's way down on my list. Looks good from the outside, though! :abd:
Looks not "good." Looks beautiful l!! I continue to be amazed by your upgrades.
Maybe a rainy WEEKEND terminals project?
I know what a pita that space can be and then there's the issue of enuf slack to replace them. IIWM I'd think about salvaging the terminals and ending up with a 99% improvement, albeit not 100%.
I installed that jumper when I rewired my boat. I was told on this forum, with an ELCI breaker it was not necessary, it's also "controversial" so I removed the AC ground to DC negative jumper behind the main distribution panel.
There was also lots of dialogue to connect the DC negative to the start motor bolt, and not the bell housing. If a sea water ground isn't required why terminate DC negative on the starter to engine bolt at all?
Jon
I missed your earlier question. No, there's no code for a "seawater ground" (DC or AC.) In fact, a seawater AC ground would be dangerous (in the absence of a bond DC neg --> AC ground) and is why abyc calls for bonding together the two busses (ELCi discussed later.) Why is that? If the DC became energized w/ 120 vac (leakage or a fault) then the ground (prop shaft or whatever) can become a cattle prod to someone in the water. Bonding the DC to the AC provides a safer, lower resistance, path for 120vac, rather than thru a person's body.
Did you install that jumper or
remove that jumper when you rewired?
(you said)
Quote
No GI, and AC not connected to 12vdc negative buss
The "controversy" you mention -- is that galvanic corrosion caused by leakage from other boats at the marina is because we are connected together by the common AC ground wire (and the corrosion to our boats by the DC -> AC bond wire.) Removing the bond eliminates that path.
I recall the earlier discussion on ELCIs. Apologies for not expanding on "unnecessary" back then -- but for background, a whole-boat ELCI does not remove the ABYC "(voluntary) requirement" to bond the DC neg > AC ground -- the reasoning being that an ELCI could fail (extremely rare) and the DC -> AC bond is belt/suspenders. So, bonding is theoretically unnecessary but still required. True, with the ELCI there's a very valid argument that the possibility of a fault making its way into the water is so VERY VERY SLIGHT so that the DC > AC bond becomes unnecessary. The decision of whether or not to bond DC -> AC becomes a personal choice (acceptable risk.)
Another way to think of it -- I run a GFCI-protected circuit for a pool filter and underwater lighting -- so the ground on the pump and the underwater lighting become unnecessary. But I wouldn't cut off the 3rd prong on the pump plug or disconnect the ground wire on the receptacle. Or closer to home, I wouldn't cut off the ground prong on a shore cable because the ELCI will protect against electrocution on the boat.
I know an electrician who touts how sternly he follows the National Electrical Code when wiring his boat, yet refuses to follow that (voluntary) ABYC bonding requirement. He's calculated out the theoretical chance of a fault to the nth decimal place (and I agree with his very small theoretical chance of someone getting hurt.) His problem with it is just that he simply won't comply w/ a code that he doesn't agree with. He could install a 100$ GI (he has enough spare bucks) and would then be both compliant and protected from corrosion, but he just ain't gonna do it because...
He's pretty hypocritical because he'll chastise owners for not following, say, some manufacturer's recommendation (that is merely a recommendation, not a code or requirement.)
I digressed.
Quote
If a sea water ground isn't required why terminate DC negative on the starter to engine bolt at all?
That's unrelated to a ground (earth) path -- an engine negative battery connection is necessary for the starter, glow plugs, temp gauge sender, and temp and oil pressure switches. The reason for moving the cable is that the starter is where high power is needed so there is a better electrical connection than to the bell housing.
-k
Hi Ken, thanks for the response my friend.
I don't remember if the jumper was there orignally. I don't seem to have a before photo of the AC and DC negative buss to check. As part of my electrical upgrade project, I initially installed the jumper from the AC ground buss to the DC negative buss. After discussions here, and what I read in other forums, I removed the jumper.
For reference the main AC from the dock goes through a SmartPlug then to the main breaker which is a 30A ELCI breaker for system protection. Any leakage from the water heater, or AC charger should trip the ELCI. Also lots of discussion about the risk of nuisance trips from the water heater with an ELCI. I don't use the hot water heater that often, but no trips of any kind so far. My 4 AC outlets in the boat are GFCI protected.
I've been out of the spec reading business for a while now. I recall "recommended" and "mandatory" requirements. What's meant by "voluntary" requirement?
Jon
No agency enforces ABYC. The coast guard has its own requirements and abyc isn't one of them it requires manufacturers to follow. So, owners and manufacturers following it is 'voluntary.' So, Catalina could build a boat and not follow that standard 100% (and still does.)
Now, an insurance company will require that aspects be followed, but they also aren't required to do that by any govt agency.
On the other hand, abyc publishes 'guides' that have examples how to meet certain CG requirements but abyc isn't the "standard" - the CG sets the standard.
Contrast that to another non-government-prepared/issued standard like the National Electrical Code. States, cities, counties require builders to follow that code, so it's not voluntary.
Lots to digest, main thing I took away from all the replies is I don't need to worry about somehow bonding the shaft with the engine for a dc ground. Also my question was not in regards of lightning strikes but more in eliminating as much possibility of corrosion to my prop and possibility of getting zapped. I'm a diver and clean my own bottom regularly so I don't want to create a situation in which getting electrocuted underwater is a possibility LOL.
The ABYC standards are very clear on the use of flexible couplings:
"6.5.5.2 If a non-conductive flexible coupling is used, an alternative means of grounding the shaft must be provided."
Thank you for clarifying that, Rod
What purpose does that serve?
-k
Quote from: KWKloeber on February 22, 2021, 03:42:48 PM
The coast guard has its own requirements and abyc isn't one of them it requires manufacturers to follow.
The CFR/USGC requirements are derived in-part from the ABYC standards with some minor tweaks here and there. The USCG is directly involved in the ABYC standards development and the ABYC in aiding the USCG on the CFR standards where applicable.. There is a USCG representative in attendance at nearly every one of the PTC meetings. To say "the Coast Guard has its own requirements and ABYC isn't one of them" is an odd statement as they work in concert on a lot of it..
Ok, so if an alternate ground is needed can I use my prop strut as a grounding point? Does grounding something "invite" extra corrosion?
Quote from: mainesail
To say "the Coast Guard has its own requirements and ABYC isn't one of them" is misleading at best.
au contraire, Rod. That statement was 100% correct.
To imply that the CG enforces ABYC because it "participates" in developing an ABYC standard is not misleading "at best" but misleading period. The CG DOES NOT enforce ABYC. Period.
is there a CFR citation that states that boaters must follow any ABYC standard or that vessels must comply with any ABYC standard?
Having input to an enforceable govt code does not equate to that govt agency enforcing anything other than the code it promulgates. C'mon, you know the difference.
If asked, "CG, do you enforce ABYC Standards or do you have your own standards?"-- you know what the response will be.
ABYC is a voluntary "trade group" standard. That is unlike say, when a state or federal code states that an oil storage tank SHALL be inspected according to standard NFPA # xyz.
In that case, the trade group standard
is enforcable. That's not the case here.
Quote from: KWKloeber on February 23, 2021, 10:40:34 AM
Quote from: mainesail
To say "the Coast Guard has its own requirements and ABYC isn't one of them" is misleading at best.
au contraire, Rod. That statement was 100% correct.
Ken,
This will be my last response to you.
One example is ABYC A-16 navigation light certifications. ABYC A-16 is enforceable under the CFR. Why? because the Feds simply adopted (incorporated by reference) ABYC A-16 as part of the CFR requirement. This makes ABYC A-16 part of Federal law and enforceable by the Government standards.. The CFR also adopts many other standards not enforceable by law on their own such as SAE, NFPA, UL and others.
QuoteThe CG DOES NOT enforce ABYC. Period.
In the example above ABYC A-16 is fully enforceable by law under the CFR because it is incorporated into the CFR.
Quoteis there a CFR citation that states that boaters must follow any ABYC standard or that vessels must comply with any ABYC standard?
Not at all what I said. However boaters should always try and follow the ABYC guidelines when doing work on their boats. I say this not only as a boat owner, marine electrician, a member of the ABYC hull piping, electrical and Li-Ion PTC's at ABYC, but also as an expert witness in this field.
QuoteABYC is a voluntary "trade group" standard.
Yes, it is.
QuoteThat is unlike say, when a state or federal code states that an oil storage tank SHALL be inspected according to standard NFPA # xyz.
In that case, the trade group standard is enforcable. That's not the case here.
It is when the Federal Government adopts/incorporates ABYC standards, or parts of them, into the CFR as in the example above. ABYC A-16 is not the only ABYC standard that has been incorporated by reference into the CFR.
Quote from: Jon W
I recall "recommended" and "mandatory" requirements. What's meant by "voluntary" requirement?
Jon to frame a little tighter what I meant by voluntary standard, I'll use Rod's post from 2009 (referring to bonding the prop shaft) which explains it well -
"
ABYC is NOT mandatory but a suggested good standard based on years of combined experience by its many voting members."
When no one (i.e., states, CG, etc.) enforces a standard (i.e., "NOT mandatory"), it's use is "voluntary." But mea culpa - my using "voluntary" with "requirement" was an oxymoron. I should have written "ABYC (voluntary) standard" rather than "requirement."
There's no ABYC Police so the use of "must" is pretty meaningless. One "must" take an action in order to comply with that standard, but the standard itself is voluntary -- so it's circular reasoning.
A "must" code is different from stating a fact (e.g., to bond the AC to DC one "must" jumper between the two busses.) That's true whether or not the owner decides to do it.
This is in no way meant to imply that any particular ABYC standard is bogus, or that insurance companies don't rely on it -- but pointing out facts that are facts.
-k
Quote from: mainesail link=topic=10928.msg86082
"6.5.5.2 If a non-conductive flexible coupling is used,b]an alternative means of grounding the shaft must be provided[/b]."
Mainesail, can you please explain the reason for this? Is it an AC, DC (or both) shock protection issue or...? And, as Alex asked, can one use the strut as a ground if shaft is isolated by flexible coupling? Also, how much resistance measured between engine and shaft is permissible.
What's the composition of the cutlass bearing? Mine looked to be composite material no metal. If no metal, it would isolate the shaft from the strut so wouldn't provide a ground.
Think what Alex was asking is if one were to attach a ground wire to the strut bolts inside the boat, would that give an acceptable path to seawater if the rubber lining in the cutlass bearing and a flexible coupler are isolating the shaft. Would that be a acceptable alternate ground path INSTEAD of the shaft.
Quote from: Jon W on February 23, 2021, 02:24:41 PM
What's the composition of the cutlass bearing? Mine looked to be composite material no metal. If no metal, it would isolate the shaft from the strut so wouldn't provide a ground.
Jon,
Regardless of whether the bearing shell is brass or composite, the rubber inside insulates the strut from the shaft.
Quote from: mainesail
...the Feds simply adopted (incorporated by reference) ABYC A-16 as part of the CFR requirement.
Mates, I think key is to understand differences between citing technical manufacturing standards and "enforcing" standards or codes that involves an action. Granted, it's oftentimes challenging to accurately interpret Fed regs -- there's another famous (maybe infamous?) Fed reg example involving displaying documentation numbers.
The Feds DID NOT adopt A-16.
The CFR incorporates A-16 ONLY to this extent: lights must "Be certified by a laboratory listed by the Coast Guard to the standards of ABYC A-16." In English: "We (the CG) allow a light that a lab (that we approve of) certifies it meets A-16." Way different. A-16 also covers installation and the CG reg doesn't say boaters must "install lights per A-16." CG has its own reg for that.
So no, the CG doesn't enforce A-16 -- Coasties don't carry a copy of and enforce A-16 when they board your boat. Maybe it's a misunderstood or imperceptible difference, but it's an important difference when it comes to regulations.
In fact, if you look at A-16, 95% of it merely copies COLREGS. Does that equate to ABYC enforcing COLREGS? No.
A-16 also cites the Society of Automotive Engineers, so does that equate to ABYC enforcing SAE requirements? No.
Quote
boaters should always try and follow the ABYC guidelines when doing work on their boats.
No question!! To the extent possible and appropriate.
The reason I split this thread earlier, from the "re-wiring my boat" thread, was to hopefully have some expert(s) weigh-in on what is the science/reasoning behind requiring the prop shaft provide an electrical path from inside the boat (either AC or DC or both), to the sea. Unfortunately, I am still unclear about what the reasoning is.
Noah, think it was Antoni, but I didn't think of tieing the internal strut bolts to a shaft or flange hub rotating at 800-3,000 rpm. Why not use the silver impregnated rubber strip intended for this purpose available from R&D mentioned in his first post of this thread?
Well Ken I was going to say the cutlass bearing electrically isolates the shaft from the strut, but thought someone would comment it depends on the material composition (like the silver impregnated rubber strip) so tried to head that off by providing a caveat.
Jon—I am not talking about connecting the shaft to anything. Alex asked about tying the strut to electrical system to bypass a need to include shaft. There are lots of devices to tie or jumper flexible couplings (silver impregnated wire for R&D couplers, or external shaft brushes), but I want to know WHY it is needed at all. Notably, Vetus, makers of the Bullflex coupler that I have, doesn't mention the need nor market a jumper, that I could find. Why? Maybe because it is made in Europe and a ABYC recommendations don't apply?? I would like to know the logic/need to connect the shaft. I am a sailor not an electrician, so I am NOT knowledgeable in this subject, thus the call for expert help.
Mainesail's post says the shaft must be grounded. How do you ground it without connecting to it? I'm looking forward to the reasons behind the requirement as well. Guess it isn't my night. Quick look at my watch and realize it's tequila time. :clap
Mainesail's post said: "6.5.5.2 If a non-conductive flexible coupling is used, an alternative means of grounding the shaft must be provided."
An "alternative means" could perhaps be provided by the strut. (?)
I'm going to guess that the reason for the prop shaft ground is that in case for some reason the AC neutral/ground is lost. The AC neutral would be replaced by the DC ground to sea water.
Any divers in the water are considered collateral karma.
I am also wondering how much resistance is deemed to be "non-conductive"? Lots of question here...
I ask questions in a weird way sometimes, English isn't my first language but I don't think it's a language thing LOL. What I asked originally is. Since I have a flexible coupler that breaks the electrical continuity to the shaft and the grounds that are connected to the block no longer have a path to seawater can that path be restore by grounding to one of the bolts that hold the prop strut on. No that will not re establish an electrical continuity to the prop shaft as the cutlass bearing has a rubber sleeve, but I don't think the requirement is to be specifically grounded thru the shaft, but more so to have a ground that goes to sea water.
The other question related to that is, does a dc ground connected directly to a bronze fitting that's underwater "invite" extra corrosion? If so then using the prop strut wouldn't be a good idea, in which case I'd opt to install a sintered bronze plate for my grounding.
I've got 2 days before I hit the water, let's come to a consensus quick yeah? Lol
I like this guys inexpensive solution:
https://www.cruisersforum.com/forums/f114/grounding-shaft-with-a-driversaver-56582.html#post648238
Quote from: Noah on February 23, 2021, 04:24:35 PM
reasoning behind requiring the prop shaft provide an electrical path from inside the boat (either AC or DC or both), to the sea.
Noah
The DC has nothing to do with it. The DC battery isn't referenced to earth as AC is, so connecting DC equipment to earth does basically nothing because there is no completed circuit.
As I said previously I feel it's best to bond as much together as possible (as practical) for the purpose of galvanic corrosion, then everything's at the same voltage potential, and if there's multiple anodes they act together. But as I said the Hx (which will be a local battery due to the different metals immersed in electrolyte) will be protected by itself (by its own anode) even if the Hx is not bonded to the engine, etc. However, it's best to bond the Hx (but most do not) -- so likewise a shaft (if having an anode) is protected even if not bonded (same as a strut.) A strut oftentimes gets painted (or oxidized) and it doesn't make a really great earth ground, but if bonded it's better than not being bonded.
EVERYTHING once you step onto a boat are trade-offs and a compromises.
Now as far as AC, what I said before, the shaft can become a cattle prod and hurt/kill someone (even not in the water.) So is that better, or is it better to protect what's/who's aboard the boat?
If the shore cable loses the ground - Say something goes hot through a fault -- there's no ground to safely bleed it off. But bleeding off thru the prop shaft turns that into the cattle prod. It's possible that could continue for a long time without an indication of a problem.
If an ELCI is installed that's the best solution -- the threat of an undetected fault is VERY VERY VERY low, like near zero, then you won't turn the shaft into a hot prod. Because that takes two actions -- losing the ground and the ELCI failing.
If no ELCI, one can at least install a $3.00 120v indicator light (like BlueSea, green indicating bond/ground) between the AC hot and ground -- as soon as you get on the boat you see that you have the ground connection. (On yours it could be put near the main breaker.)
Note that testing a GFCI outlet
DOES NOT test the AC ground.
Or one could keep a $5 outlet tester plugged in (which shows correct wiring, open ground, reverse polarity, etc.)
Caveat - that's not a "professional" opinion you sought -- it's a "practical" opinion -- because a professional must say "follow ABYC" (even if outdated and not making sense.)
So I get that when plugged into shore power and as long as the marina is wired correctly I'm ok, but what happens if I add an inverter on board? Or bring my little Honda 2000 generator? Wouldn't it be necessary to have a ground to sea in that case in order to be safe? How does it affect swimmers around the boat? What are the potential issues?
Guys : I'm not an electrical whiz nor idiot. Your auto is a DC system like the boat and is not grounded !!
The only reasons that I plug unto shore power is :
1. to have the AC powered battery charger charge my DC batteries!!
2. power my closed AC outlet circuits, so I can run an AC tool or an AC appliance.
I see no reason then to have the prop shaft grounded to the DC engine!!
A few thoughts
I just realized why Mainsail has sworn off this one.
Logo
This doesn't address your question per se re: the shaft but it is interesting in that it discusses the intricate nuances about grounding and what can go wrong if you're using a genset or inverter.
Guys : I have used my Honda 1000 for years and so has hundreds of other C34s - especially those that use the East Coast ICW and the Bahamas!!!
If your C34 is wired properly, you shouldn't ever have a problem with a generator or a properly installed inverter!! Regardless, if your drive shaft is grounded or not.
A thought