Anyone know about petrol mixed with 12volt electrics ?

chaparral · 18 Jul 2016 at 19:20

Had problems with my motorbike not starting and after noticing that about a litre of water has somehow got into the fuel tank I removed the broken fuel pump and notice this...
I never knew you could have just normal 12volt electric spade connectors like this inside a petrol fuel tank :eek:

I took these pictures below of where my fuel pump connects inside my motorbike petrol fuel tank

Dup · 18 Jul 2016 at 19:24

Petrol AFAIK is not conductive. Quite common cars having in tank pumps with bare connectors.

That looks like it's seen better days though.

chaparral · 18 Jul 2016 at 19:35

Dup said:
Petrol AFAIK is not conductive. Quite common cars having in tank pumps with bare connectors.

It just gave me a bit of a surprise when I saw them spade connectors with bare metal showing when I know very well what sparks you get if you touch 12 volt live & earth wires together..

Greebo · 19 Jul 2016 at 00:00

Petrol is quite hard to ignite. Hell you can drop a lit cigarette into petrol and it won't ignite.

They even tested it by spraying a fine mist of petrol at a lit cigarette and it didn't ignite.

Movies eh?

You need a mix of 1 to 7% petrol to air. Any less or anymore and petrol won't ignite.

So those 12v Sparks won't do anything in your petrol tank.

Destination · 19 Jul 2016 at 02:43

Are you sure?
I thought th gasoline vapour and flash point was below zero, even in the snow it'll give off vapours that will ignite if they find a combustion source, bare flame etc?

mushtafa · 19 Jul 2016 at 07:26

It' the vapour you have to worry about, not the liquid fuel.

99% of cars have electrics inside the fuel tank.

wolfie138 · 19 Jul 2016 at 09:01

Greebo said:
Petrol is quite hard to ignite. Hell you can drop a lit cigarette into petrol and it won't ignite.

They even tested it by spraying a fine mist of petrol at a lit cigarette and it didn't ignite.

Movies eh?

You need a mix of 1 to 7% petrol to air. Any less or anymore and petrol won't ignite.

So those 12v Sparks won't do anything in your petrol tank.

what? then how come a crashed tanker exploded when people stealing the gasoline were smoking around it etc? Petrol is VERY combustible, the vapour even more so.

Tefal · 19 Jul 2016 at 09:03

We have bare screwed in fork and ring terminals inside the fuel tanks of airliners

Its low voltage and current you won't get a spark.
Plus its under petrol so no air to spark anyway

Tefal · 19 Jul 2016 at 09:04

wolfie138 said:
what? then how come a crashed tanker exploded when people stealing the gasoline were smoking around it etc? Petrol is VERY combustible, the vapour even more so.

As you said vapour.

Your tank will never get that empty unless you opwn it up and start blowing compreased air or a hairdryer in there to get all the residue out

kae2 · 19 Jul 2016 at 09:07

Greebo said:
Petrol is quite hard to ignite. Hell you can drop a lit cigarette into petrol and it won't ignite.

They even tested it by spraying a fine mist of petrol at a lit cigarette and it didn't ignite.

Movies eh?

You need a mix of 1 to 7% petrol to air. Any less or anymore and petrol won't ignite.

So those 12v Sparks won't do anything in your petrol tank.

You might be thinking of diesel...... petrol vapour is very bangy

Submersed 12v electrics are very common in petrol tanks. The verdigris on the connections will be from the water in the bottom of your tank. Quick clean and you'll be back in business.

Orionaut · 19 Jul 2016 at 09:13

as has been said already. Petrol will not burn or explode unles there is a fair amount of oxygen present.

There is no oxygen in the liquid, submerged electrics are fine, even if they spark.

The vapour above the liquid in the typical fuel tank will have displaced most of the gaseous oxygen so that even there sparks are not likely to be an issue

(I have seen film of veritable lightening storms going on in aircraft fuel tanks due to static discharge during high speed filling, as long as no air is present, this is not a problem)

As an aside, the traditional way of extinguishing spontaneous combustion fires in cotton bales was to soak them in petrol. The Petrol is less viscous than water so can soak into the fibres and exclude oxygen and cool the fire. The outside of the bale is soaked in water to prevent free petrol from burning in air