How does an electric fuel pump inside a tank not start a fire?

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Old 07-01-2010, 03:45 PM
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Default How does an electric fuel pump inside a tank not start a fire?

Question,
After evaluating the design of the fuel pump assembly in my 96 Camaro, I am left with a question of "How does the electrical connections in the fuel pump assembly not start a fire?"

There are exposed wire connections points on the fuel pump assembly that sit in the gas tank.

Is it because the pump creates a vacuum that prevents a fire(lack of oxygen)? or Even though the wires carry electrical current, but do not cause a spark is that how it is safe?
 
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Old 07-01-2010, 03:53 PM
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DC / AC current; not enough oxygen or compression to support combustion.
 
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Old 07-01-2010, 05:26 PM
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well you dont want lose connections in there. the pump is also sealed quite well. all the newer gm cars and trucks have the fuel pumps in the tank. its not so hard for the pump to reach the pressure needed for fuel injection (tpi and tbi) if its submerged. pump lasts longer,,, well a good pump does.
 
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Old 07-03-2010, 08:58 PM
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There is not enough air in the gas tank to support combustion. Way too much fuel for the available air. However; if the proper proprtion of gas fumes and air are present, a spark inside the tank may result in an explosion. The pump is submerged in fuel, so there is no chance for it to start a fire, and it is fused so that the fuse blows before wires get too hot from electrical overload.
 
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Old 07-03-2010, 09:37 PM
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Grab a 5 gallon jug of gas, light a match, and throw it in. Nothing will happen, there isn't enough air, and gas will only ignight as fumes. Not to mention the sucking sound I hear when I remove the gas cap. If the tank was almost empty, just a bit of gas in the bottom, and the gas cap was off to let air in, and a loose connection caused a spark in the right place it could explode. I personally wouldn't recomend it, as it may slightly damage the back seats.
 
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Old 07-03-2010, 11:47 PM
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the electrical connections inside the tank for the pump are not, if properly tightened, going to arc. The pump motor is sealed and the brushes used are usually a non arcing type any way. The other factor is as listed above not enough o2 to support ignition. The fuel in the tank also keeps things cool which helps keep the pump from burning up.

Massey
 
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Old 07-04-2010, 11:03 AM
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Originally Posted by ryguy425425
Grab a 5 gallon jug of gas, light a match, and throw it in. Nothing will happen,
Whatever you do, don't even suggest someone doing that, even in jest. If some nitwit were to read that and actually try it, with 5 gallons of gas, they could get seriously burned.

I know what you are trying to say, there is way too much fuel and not nearly enough oxygen to combust in that scenario.

To the OP, you need three things to have a fire: Heat, Oxygen, and Fuel. It is the fire triangle, and if you remove one of the three sides, the triangle collapses and the fire extinguishes.

Since the fuel pump is submerged in the gas, there is no oxygen available to ignite even if there was a spark to provide the heat. You would only have fuel and heat, thus no fire.
 

Last edited by Grandpaswagon; 07-04-2010 at 11:07 AM.
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Old 07-04-2010, 02:36 PM
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In order to throw a lit match into a 5 gallon can of gas, the container would have to be open, and the gas would be emitting explosive fumes.
You will blow yourself up. If you value your life, I highly recommend not trying that experiment.
 

Last edited by Camaro 69; 07-04-2010 at 02:38 PM.
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Old 07-04-2010, 06:24 PM
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but cigarettes cant light gas no matter what ive tested it and ive never blown up
 
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Old 07-04-2010, 06:57 PM
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Originally Posted by BasicConcepts
but cigarettes cant light gas no matter what ive tested it and ive never blown up
They tested that on Mythbusters too.
 


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