A Disaster Averted!

[bvassel3]

Many of you are aware that we have been on a 3,500 mile boating trip taking the Down East Circle Route in the Northeastern States and Canada. Well today we left Rimouski, Canada and headed down river again. The water no longer resembles a river but appears to be the ocean. Our destination was Matane, about a 60 mile run.

A boater?s worst nightmare almost happen to us in the Matane, Canada Marina.

As is customary, when gassing up a boat at a gas dock in a marina, you turn off all electrical devices on your boat ? generator,circuit breakers, and let your engine-compartment blower run for a few minutes to expel all gas fumes to eliminate all possibilities of a spark-causing fire.

What you don?t expect is that the gas pump itself could cause a spark. Have you ever heard of a gasoline pump nozzle having an electric current running through it, enough to cause sparks right when the nozzle touches the gas-cap opening? That would be unheard of.

Well, that happen to me today. The attendant handed me the gas nozzle, and with the gas cap off, exposing the opening to the gas tank, and when the metal gas nozzle touched the metal opening to the gas tank, sparks flew, causing a small fire around the opening of the gas tank. I even felt a shock when this all happened.

We were fortunate to extinguish the flame immediately.

A mechanic came out with a voltage meter and determined that there were 110 volts coming through the gas metal nozzle. Evidently gas nozzles are wired from the pump, down through the hose to the nozzle, to allow it to shut off. Something was shorting out through the process on this pump.

So to avoid further risk, I got a plastic 5 gallon gas can and had the attendant fill it 12 times as I poured the gas into the boat?s tanks from the plastic gas can. I wanted to top off the gas as we are going over 200 miles tomorrow and I needed a reserve amount of fuel.

Needless to say, this could have been a huge diaster, with a bad ending. We certainly had someone watching over us. We will say extra prayers of thanks to the Good Lord tonight!

I would be interested to know why and how something like this can happen. I've never heard of 110 volts going through a gas hose and nozzle.

Any opinions out there?

Captain Bruno of the iboats' Pursuit boat.

 

[vintageglass]

Re: A Disaster Averted!

I've never seen 110 power at the nozzle but I do know you can get a nasty spark from static electricity if the filler ring is not grounded. I've seen race cars go up in flames like that. I worked for a few seasons pumping race fuel, both in cars and to jugs, the filler nozzle had an attached ground strap which was connected first to the filler ring or fill port. Jugs were only allowed to be filled on the ground away from any cars or the tank.

When we filled a race car, we would attach a ground strap both from the filler to the body of the car, and another from that one to the nozzle away from the car before pumping just in case the builder of the car didn't include a proper ground.

I've seen or felt static charge when filling several boats but never had one ignite. On my glass hulls with built in tanks the filler neck is grounded to the tank, and the tank grounded to the electrical system.

I can't say I've got any in depth knowledge of how a gas pump works, but I have dealt with a few and its nearly impossible for one to short out that way from what I've seen. I would more likely suspect a bad ground somewhere on the pump, pump hose, or the dock itself somehow.

A quick search found this online, Grounding a Plastic Gas Tank | Boatbuilding Blog

 

[Grandad]

Re: A Disaster Averted!

I'm surprised that the electrician didn't insist that the pump be locked out from use immediately. The nozzle of the filler is required to be connected ("bonded") back to the pump and any metal fittings on shore, which are in turn grounded back at the electrical distribution system's ground source. The intent is to ensure that no metal parts can ever become alive. The weak part in the plan is that because of improper installation or maintenance, the ground source can become disconnected from these bonded together metal parts.

Under such circumstances, any failed component such as a fuel dispenser light or pump motor (or dock light for that matter) can make all of those bonded parts alive, each of them searching for a path to ground. Evidently the now live fuel nozzle found a path to ground through your boat's properly bonded system to the water through your boat's submersed metal parts. The same would continue to happen to the next boats to fill until disaster inevitably strikes. Assuming the electrician knew his stuff and found a significant sustained voltage on the dispenser, the marina is at fault, not you or static. That said, the static straps often recommended but usually ignored, would have prevented the arc from occurring directly at your fill pipe. - Grandad

 

[oldjeep]

Re: A Disaster Averted!

I'm surprised that the electrician didn't insist that the pump be locked out from use immediately.

x2 - I'm amazed that they would even take the risk of using it after that.

 

[gm280]

Re: A Disaster Averted!

Glad to hear you adverted a major disaster, but seems the marina is still playing with one, a BIG serious one too!!! You need to report that issue to the proper authorities if it hasn't been fixed already. You could save some people's lives...

 

[GA_Boater]

Re: A Disaster Averted!

Whoa - There is NO such thing as a "small fire around the opening of the gas tank". You missed the big one! Just think if you had squeezed the handle when you got shocked and starting pumping fuel while the nozzle wasn't fully in the filler. End of adventure and possibly much worse!

There is no electrical power through the hose to the nozzle. The auto shut-off is done mechanically by the nozzle sensing pressure backing up when the tank is full. The pump and/or fuel dock has a serious electrical fault in the grounding or a short. Something is not right in the Ground Fault Circuit Isolation.

That fuel dock should be shut down immediately until the cause is found and repaired.

Enjoy the continuing voyage and a safe return to Cape Cod.

 

[LippCJ7]

Re: A Disaster Averted!

Whoa - There is NO such thing as a "small fire around the opening of the gas tank". You missed the big one! Just think if you had squeezed the handle when you got shocked and starting pumping fuel while the nozzle wasn't fully in the filler. End of adventure and possibly much worse!

There is no electrical power through the hose to the nozzle. The auto shut-off is done mechanically by the nozzle sensing pressure backing up when the tank is full. The pump and/or fuel dock has a serious electrical fault in the grounding or a short. Something is not right in the Ground Fault Circuit Isolation.

That fuel dock should be shut down immediately until the cause is found and repaired.

Enjoy the continuing voyage and a safe return to Cape Cod.

I am going with GA on this one, I don't believe there is any electrical current going to the fuel nozzle, at least not one that is in proper operational order, I agree with informing the proper authorities.

I am happy it happened to you though if that had happened to me the title of this thread would be Disaster averted, but now I am in jail for assault and battery!

 

[bvassel3]

Re: A Disaster Averted!

Given this experience, I would like your advice or input on a couple of questions:

1. What should we as boaters, or for that matter bikers or with a private plane or car, when we are refueling, learn from this?
2. How can we all avoid or insure this problem is not going on as we get ready to fill up?

Thanks. Bruno 3

 

[Grandad]

Re: A Disaster Averted!

Given this experience, I would like your advice or input on a couple of questions:

1. What should we as boaters, or for that matter bikers or with a private plane or car, when we are refueling, learn from this?
2. How can we all avoid or insure this problem is not going on as we get ready to fill up?

Thanks. Bruno 3

Well, I've made a plan. I trailer boat generally and fill when I can at auto fuel prices, rather than at marinas. Trailer boats can build static that can cause an arc to the nozzle, so I plan to touch the nozzle to a nearby stern cleat or tie-down u-bolt before removing the inboard tank fuel fill cap of my aluminum boat. I don't see why I can't do this also while filling in the water at a marina. All the filling instructions generally say that you should maintain contact between the nozzle and the fill pipe while filling, but that only bleeds a charge that might build while filling. What about a charge that's more likely to be there upon first contact. Maybe this procedure is over-kill for static, I dunno, but it would have prevented Bruno's near demise from a live nozzle. - Grandad

 

[GA_Boater]

Re: A Disaster Averted!

Your plan for static discharge is good, Grandad. But Bruno's situation was different in that he couldn't discharge until a GFCI kicked in or a circuit breaker trips. I'm at a loss for any way to prevent a situation like that. You can't do a voltage test before a fill-up. You might carry a ground wire to connect the nozzle to boat ground, but not very practical. Aircraft and fuel hoses are connected to ground, but there are provisions for the grounding.

 

[rbh]

Re: A Disaster Averted!

Well, I've made a plan. I trailer boat generally and fill when I can at auto fuel prices, rather than at marinas. Trailer boats can build static that can cause an arc to the nozzle, so I plan to touch the nozzle to a nearby stern cleat or tie-down u-bolt before removing the inboard tank fuel fill cap of my aluminum boat. I don't see why I can't do this also while filling in the water at a marina. All the filling instructions generally say that you should maintain contact between the nozzle and the fill pipe while filling, but that only bleeds a charge that might build while filling. What about a charge that's more likely to be there upon first contact. Maybe this procedure is over-kill for static, I dunno, but it would have prevented Bruno's near demise from a live nozzle. - Grandad

Next time you fuel up look for the static discharge cord, (line, ground wire), it should be there with a big alligator clamp to clamp onto the grounded, bonded fuel receptacle, inlet.

I think by law they are required.

 

[bvassel3]

Re: A Disaster Averted!

Thank you for your suggestions. As GA_Boater indicated my situation was not a static discharge, it was a short from a 110 volt connection somewhere in the gas pump. Never heard or encountered such a thing before.

 

[Grandad]

Re: A Disaster Averted!

Thank you for your suggestions. As GA_Boater indicated my situation was not a static discharge, it was a short from a 110 volt connection somewhere in the gas pump. Never heard or encountered such a thing before.

Shorting the nozzle to a grounded fitting on your boat away from the gas fill pipe will show any potential difference between the 2 metal parts. In the case of static only, it would equalize the charge and avoid a static spark. In your situation Bruno, the live nozzle would have produced a 120V arc at the fitting, probably taking out an onshore breaker and a chunk of metal out of both nozzle and fitting. A pitted fitting is better than what could otherwise ensue at the fill pipe.

GA - I'm not aware of a requirement for GFCI protection of a gas pump, so expecting that to trip is pointless. The short circuit fault could actually be anywhere in the distribution system that feeds the pump and would make the entire network of bonded equipment alive if the ground connection was incomplete as it must have been where Bruno filled up. - Grandad