Earthing

Generally, earthing is done to get rid of static electricity (& lightning) that may spark & cause fire. Now coming to pump, if it is an externally mounted pump, what they say is not true. If the pump is connected to battery source of the truck, then it may or may not require the ground based on surrounding conditions.

Take a look at the below website. It is very self explanatory.

http://www.staticelectricity.com.au/index_NewsonGale.php

Thanks Guys

http://www.staticelectricity.com.au/index_NewsonGale.php

That website answered all the questions.

When any vehicle is in motion it generate static charge. This charge if not properly earthed can cause electrical spark. The spark can cause fire if it happens while the petrol/diesel is pumped . To avoid any fire hazard the truck is earthed first before the pump is started.The operation of the relay for the pump motor is interlocked with the earth connection of the truck to avoid manual error of not connecting the earth as a safety precaution.

A Spark can cause a fire any time there is fuel vapour available in the area where the spark (ignition point) is located, this could also be in the hoses and/or the fittings that are being used to transfer the fuel.

Remember, Fuel (liquad) will not burn, but the gasses of the fuel is what burns (explodes when in the wrong conditions)

My friend,

Many fuel depots' electrical designs include primarilly the grounding system (earthing) of all exposed steel structures and one of them is the motor pump aside from area classification requirements.

It is normal to all fuel depot that wasted fuel flowing from the tankers, spill over and leaks are accummulated to the ground or flooring of the fuel depot. In usual way, this should clean once in a while, but if the depot does not have good maintenance and house keeping, it will happened just what you have seen.

Don't you worry about the static current that might be a source of disastrous incident (fire and explosion). It will not be happened since all steel structures are fully grounded, it is matter of maintenance (again). Retighten all grounding systems' connections exposed to untidy unloading terminal.

"The tanker should be grounded (clamps) from fuel depot grounding system before tapping or filling the tanker."

In some instances, the fuel depot is design that the above grounding to tanker gives signal (permissive) to start the filling pump, which grounding sensor (w/ relay contacts; NO and NC) connected to motor pump controller(s).

Eren

The major source of the static charge in fuel transfer systems that is bled off by bonding the various portions of the delivery system (tank - piping - pump - hose - receiving vehicle) to each other, is not caused, as has been suggested, by the motion of the vehicle through air prior to the filling process. The actual source of the static potential is the flow of hydrocarbons through the various portions of the actual delivery system.