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Fuel Tank Earth
caber - 11/1/07 at 08:56 PM

I don't have a stud on my fuel tank to use to connect an earth. I presume one is needed to the body of the tank as it is sitting in rubbers and the earth on the fuel sender is isolated from the tank body by a rubber gasket?

Do I actually need the rubbers on the tank if it is strapped down tight? I don't see this detail on production cars?

Caber

DIY Si - 11/1/07 at 09:00 PM

Most cars I've looked have rubber straps between the tank and its straps. These are older cars admittedly. Can't say as I've ever seen an earth strap though.

mookaloid - 11/1/07 at 09:06 PM

you only need to provide an earth to the sender body - I used one of the sender mounting screws to mount a permanent earth wire

HTH

Mark

caber - 11/1/07 at 09:29 PM

Hmmm, no earth, sender fails with live to tank, garage filler nozzle goes in touching petrol filler tube bolted to ally body and touches tube on tank linked by v short rubber tube, spark BANG!

Not to keen on that scenario and it is a little more likely than the urban myth spark from mobile phone in car!

Caber

PS how come no one ever worried about CB's at filling station? i would have thought the power on some of those more likely to cause spark to earth?

James - 11/1/07 at 09:34 PM

Caber,
What about jubilee clipping an earth strap to the filler neck?

I got this idea looking at the earth on the sink at work whilst sitting on the crapper!

As for the phone thing.... there was a post about this recently... I believe it's more to do with dropping the phone and it sparking rather than a spark when you're using it.

Cheers,
James

jollygreengiant - 11/1/07 at 10:07 PM

quote:
Originally posted by James
As for the phone thing.... there was a post about this recently... I believe it's more to do with dropping the phone and it sparking rather than a spark when you're using it.

Cheers,
James


Yep its all about energy.
If you drop the phone and its battery shorts out then that battery has enough energy to ignite fuel.

Same thing with smoking, the cigarette does NOT produce enough energy to ingnite fuel OR vapour, in fact you would extinguish the cigarette in fuel. The no smoking is to stop people lighting up, a match/lighter/electrical lighter has more than enough energy to ignite fuel.

Oh and while we are on the subject of ignition.
What combination of fluid and hot surface on a vehicle is GUARANTEED to produce combustion.?

David Jenkins - 11/1/07 at 10:27 PM

Brake fluid?

BTW: my fuel sender has a Lucas blade earth tag on the metalwork...

David

locoboy - 11/1/07 at 10:29 PM

quote:
Originally posted by jollygreengiant
Oh and while we are on the subject of ignition.
What combination of fluid and hot surface on a vehicle is GUARANTEED to produce combustion.?


Brake fluid?

locoboy - 11/1/07 at 10:29 PM

quote:
Originally posted by David Jenkins

BTW: my fuel sender has a Lucas blade earth tag on the metalwork...

David


But what about the TANK?

iank - 11/1/07 at 11:19 PM

Is your sender not mounted onto the tank with screws/bolts? If so the sender earth will earth the tank as well.

Peteff - 12/1/07 at 12:21 AM

Close the f**king door man, or are you an exhibitionist? Does petrol act as an earth like water otherwise an earth on the water pipes would be wasted with a plastic feed into the house?

David Jenkins - 12/1/07 at 09:16 AM

Note to self: must avoid cryptic answers!

"Brake fluid" was my answer to the "jollygreengiant" question re inflammable fluid.

My fuel sender has an earth tag. As has been suggested, the sender is screwed to the tank with steel screws, so the tank gets earthed as well.

Does that make it all clear?

David

02GF74 - 12/1/07 at 09:53 AM

quote:
Originally posted by caber
Hmmm, no earth, sender fails with live to tank, garage filler nozzle goes in touching petrol filler tube bolted to ally body and touches tube on tank linked by v short rubber tube, spark BANG!



hmmm, firstly I believe the usaul wiring is:

12 V - guage - sender - 0v.

The guage has internal resistance that will limit the current as does the sender.

If you tank is isolated, then even if it is 12 V and let's say worst case it directly connected to 12 V, if the filler neck is rubber and I'd be very sur;rised if you arrangement was metal from the filler to tank, then the tank is still isolated from the pump.

It is good practise to leave the ignition off so none of the electric, including fuel guage is live.

In other words, I donl.t think you have a problem, and if it does blow up, you'll probably not be around to argue

(I site on 10 gallons of petrol with another 10 under the passener every time I drive the Land Rover and I;m still here, ok, I've lost a leg, burnt off both ears and partially sighted in 1 eye and had 70 % burns due a tank exploding but am still here )

But going back to the question, my gut feel is that if it were me, I'd want my tank to be earthed - it is in most cars - the sender has to screw in to the metal of the tank so either put a couple of metal tabs on there or solder one onto the sender <- but the soldering is done with the sender removed from the tank

jollygreengiant - 12/1/07 at 09:38 PM

quote:
Originally posted by David Jenkins
Note to self: must avoid cryptic answers!

"Brake fluid" was my answer to the "jollygreengiant" question re inflammable fluid.

My fuel sender has an earth tag. As has been suggested, the sender is screwed to the tank with steel screws, so the tank gets earthed as well.

Does that make it all clear?

David


Yep clear as mud being sucked out of a black hole.

David Jenkins - 12/1/07 at 10:10 PM

Well, that's even more obscure than my post!

westcost1 - 19/1/07 at 12:06 PM

As for the rubber insulation strips I was looking at lorry tanks when in traffic the other day and they all have rubber inserts between the tank and straps