Fuel-filler grounding on 22 Cruiser

[Sunbeam]

Sunbeam,

Will you attach the ground wire to one of the bolts used to mount the fuel fill? Or will you attach it to the fuel fill some other way?

I took a look at my fills, which are the pair original to the boat, and which I have removed at the moment. I think they're Sea Dogs, but anyway, the typical metal fill fitting. There is no special tang or place to put a grounding screw. I had to look to remind myself, but the fills were originally attached with "pointy screws" into blind holes. However, when I overdrilled and filled the holes, I made it so I could go back in with machine screws if I wanted to. So, I'll put at least one machine screw on each fill (if not all three), and run wires from those to the negative bus.

Learned some new things today :thup

Sunbeam :hot

 

[Will-C]

We have an 08 Venture with aluminum tanks. A heavier green wire is attached to the sending unit which is a ground. Our metal fuel fills have rubber hoses on the fills that connect to the fuel tank. The metal fills are in fiberglass. There is nothing to conduct electricity from the fill to the tank. If the fill hose from the fuel the fuel supplier is grounded and electricity seeks ground I'm not following the need for grounding the fuel fill thats surrounded by fiberglass with the connection to the tank being a rubber hose. The factory didn't see the need to either. Since your fuel fills aren't equipped with grounding lugs or screws this seems to be a witch hunt. I mean I have been wrong before but I can't get my head around why this could be a problem. I don't remember seeing ground wires available at fuel stations for boats or cars. I hauled gas in 8000 gallon tankers years ago and we used a ground clamp that was connected to a ground clamp. But the spiller from the fuel farm was aluminum as was the trailer so there was metal to metal contact. They used to say if the tanker had been used to haul diesel fuel previous to loading gas that you should add the first couple hundred gallons of gas slowly as there was a potential static hazard because of possible friction between the aluminum tank and diesel fuel and the gasoline. I'm not trying start an argument. I'm just trying understand the concept of why the fuel fill in a C-Dory's application needs to be grounded.
D.D.

 

[Sunbeam]

Since your fuel fills aren't equipped with grounding lugs or screws this seems to be a witch hunt.

I don't think that in and of itself indicates whether or not they should be grounded, because one of the three fasteners can be used. For example, this is in the description of a "classic" Attwood stainless fuel fill (which is just like the Sea Dogs on my boat and appears to have no dedicated grounding spot):

Note: Requires a bonding wire to prevent sparking when nozzle is inserted on gas model.

Perhaps this is because the same fills are made for diesel and water (which don't need to be grounded), and it is only the cap that is different (it is molded with the words "gas," "diesel," or "water" in it) -- but of course they are not going to put a grounding spot on the cap, and all three fill bodies are the same.

On an overall note:

Sorry if this comes across as a witch hunt. I believe the question was brought up originally because a C-Brat's fills (or tanks?) were grounded originally, and he wondered whether to replace the grounding wires during a re-fit. Seemed like a reasonable question to me, and I do have my fills out of the boat while I replace the tanks/hoses/clamps, so I took an additional interest. For me, putting something back in (potentially) wrong is different from just leaving it alone as-is.

From reading standards and speaking to ABYC today, it appears that the potential problem (albeit possibly rare?) concerns metal fills, even when connected to the fuel system with rubber fuel hose (which is typical). I'm no expert - far, far from it - but my understanding now is that the potential issue is static electricity, which can build up in plastic tanks for various reasons (including swirling fuel when filling). If you also have a plastic fuel fill then there is no potential problem. If you have a metal one, there is a potential problem. With this combination, it's the fill that is supposed to be grounded, not the tank. Metal tanks are probably different in this regard? I don't know because I was checking on the plastic tank/metal fill combo.

Here is the ABYC guideline from their standard H-24, which is for gasoline fuel systems:

24.15 FUEL SYSTEM GROUNDING
Each metal or metallic plated component of the fuel fill system and fuel tank, which is in contact with the fuel, must be grounded so that its resistance to the boat's ground is less than one olnn. Wire ends shall not be clamped between the fill pipes and hose.

In areas where I'm more familiar with the overall situation (which is not electricity), I have found that ABYC is a reasonable organization, and their standards are typically good guidelines for a well-made job. They are not typically nit-picky for no good reason, but on the other hand, they do sometimes "pre-correct" for a problem which will not occur most of the time, but which, in those rare occurrences where it will occur, will be catastrophic. I'd guess this is one of those examples, i.e. an ungrounded metal fill with a plastic tank will not always or even often cause a problem, but if it does it's not a pleasant one.

I will fully own that even with the research I did today, I'm no expert in electrical matters, and it's possible that I am misunderstanding something. Maybe the metal fills don't need to be grounded at all, or maybe they only need to be grounded for a very rare occurrence (that might never happen to a particular boat/boater). Maybe it's overkill. I guess each person can choose which way to go for their own installation, and/or can do more research on their own if they are so inclined. I think I'm going to go ahead and ground my fills unless I learn new information before I reinstall them (I'm always open to learning new things or understanding things better.)

Sunbeam

 

[potter water]

Simple answer is: Ground the filler back to the battery bus negative. It is simple to do and costs nothing. The logic behind government regulations takes much longer to figure out than the time it takes to follow the reg or guideline.

 

[Sunbeam]

Simple answer is: Ground the filler back to the battery bus negative

That's exactly what I decided to do after speaking with Brian at ABYC (I think I mentioned it above, but if not, here it is).

Sunbeam

PS: Although my motivation is not so much to follow a reg or guideline as it is to do what seems prudent.

 

[T.R. Bauer]

While all of that is really good to know, I am not going to worry about it. After all, a large factor not mentioned by the brain surgeons and rocket scientists on this site is the small spark generated through static electricty needs the right atmospheric conditions to materialize in the first place. Nearly always, but not always, those conditions are when it is hot and dry and those are never the days I have off anyway. But, I boat in a rain forest where most of the time you can't get a fire going with dry wood with gasoline. Heck, it is so wet that even the things designed to make sparks won't make them.

As some others have pointed out, it is a non-issue as thousands of people have filled C-Dory boats up a large number of times without incident. None the less, it is interesting to discuss

 

[jerry97230]

If you think about it, all cars are isolated from the ground by the tires.
If you fill a portable tank at a filling station you must have it on the ground to avoid possible sparks, confusing for sure.

 

[Sunbeam]

If you think about it, all cars are isolated from the ground by the tires.

However I'm thinking that the filler on a car is probably grounded to the body, which is grounded to the battery/negative? If so, the grounding would not be through the tires but would still exist.

As you said though, it can be confusing for those of us who are not electrical experts. OTOH, it's a chance to learn something new

 

[potter water]

Wait a minute! I thought I was the only rocket scientist and that there were no brain surgeons on this site. Who's hiding out, out there?

 

[thataway]

Only do Brain Surgery when not stealing Kidneys.
Actually tires can be conductive--they have carbon in the rubber. I have not measured the potential, but it is there.

Because of my back problems I tend to avoid lifting fuel cans, thus fill them in the back of the SUV--and occasionally get chewed out by some volunteer fireman. The plastic cans are not grounded any more than the plastic tanks of the C Dory are grounded. Note that one of the companies which made most plastic fuel cans was put out of business because of an issue and law suit about what was considered to be a anti flash back screen--and wasn't. (Blitz Fuel cans).

My fuel systems in the C Dory with plastic tanks are not grounded or bonded. Some of the hoses from tank to container may have wire reinforcement in them. There is potential for static electricity to form any time fuel flows--but with the plastic, there is no way to bond the tank.

Unfortunately, even in high humidity, there can be the right ratio of air to fuel to explode--but static electricity is slightly less libel to produce a spark.

 

[Will-C]

I'm now selling my damn boat too dangerous to put fuel in it. Or maybe I'll just have the fuel attendant do it while wait for the process to be over in some other zipcode. I think grounds in a car are tied to the negative side of the battery. Remember cars used to have accessory ground strap hanging underneath. I think I get one of those for the boat. What happens if you fill the boat while it's on a trailer? I guess the battery ground is all you have.
D.D.

 

[Sunbeam]

I'm now selling my damn boat too dangerous to put fuel in it.

It seems this thread has annoyed some readers. Let me just clarify my intent:

1) I have zero interest in telling anyone what they should do, or how they should set up their boat. To each their own.

2) Emurph came up with a question about grounding fuel system components, and the discussion was going on in a thread started for a different purpose, so I moved it to its own thread. I thought others might find it of interest (vs. Emurph and I discussing via PM).

3) If I had a planned trip tomorrow on my C-Dory and my fills were ungrounded would I still take the boat out? You bet I would. On the other hand, am I going to purposely reinstall the fills without grounding them? Probably not given what I have learned and how little effort it will take to ground them.

4) However, I don't expect that ungrounded fills are going to blow up very often, if ever; and I don't expect other people to set up their boats the way I do, or even change things based on this thread. I consciously did not suggest that another setup is "A dangerous accident just waiting to happen!!!" I dislike that sort of alarmist writing and the "you should do what I do or else" implications it carries.

What happens if you fill the boat while it's on a trailer? I guess the battery ground is all you have.

I'm going to ground the fills to the negative bus as suggested, so that will be using the battery/ground.

 

[Will-C]

Sunbeam,
Just a little humor. Maybe your taking this too seriously. Sorry if I offended your reporting on what your doing. I meant no harm. Your projects are always on the forum, great info. If your suggestions were for someone in particular there is always a PM. But his thread was real interesting. Keep up the good work.
D.D.

 

[C-Green]

Well lets revive this thread. I'm no electrical wiz but there are grounds and there are grounds. What I mean is that the negative post on a battery is a "ground" for a CD22. BUT when on a trailer that terminal is not grounded (think connected) to the ground (think earth), so for the CD22 electrical system it is the "ground" but for the rest of the earth it is the detached (or not connected) electrical system for the CD22. The gas station fuel nozzle is grounded to the earth but to prevent a spark with the CD22 the CD22 needs to have its negative electrical system (including a connection to the metal fuel fill) connected to the earth. However, when in the water especially salt water the negative electrical system of the CD22 is connected to the earth via the motors when they are in the water and the gas pump nozzle is grounded to earth and the earth to the water hence nozzle and fill are at the same potential - therefore no spark possible.
I have a 2002 CD22 with no filler wire and what I plan to do is when fueling anywhere loosen the metal cap all the way, touch the nozzle to the fill, remove the cap, insert the nozzle and make sure to keep the nozzle in contact with the fill until finished.

Jay

 

[shad]

I grounded my fuel fill by clamping a ground wire between a hose clamp directly to the top of the metal tube. Then ran the ground wire to a battery negative bus terminal.

Assuming the following is from the current code revision, clamping metal-to-metal should suffice. They just do not want people sandwiching the wire in between the hose.

Wire ends shall not be clamped between the fill pipes and hose.

Replacing one of the fill screws with a through bolt is a cleaner option.