Don't ground your plastic fuel fills (do bond your metal)......
 

Plastic Fuel Fill Grounding



Recent events have caused the boating industry to examine the policy
regarding the bonding of plastic body fuel fills with metallic caps and
retaining chains. Existing USCG & ABYC policy states that the bonding
of these components is voluntary. A study by IMANNA Laboratories has
shown that connecting the metallic retaining chain and cap of a plastic
body fuel fill assembly to a boats bonding system may result in
electrostatic discharge from a land-based fuel pump nozzle to the
metallic components of the assembly when the boat is not in the water.
This condition does not exist when the boat is in the water due to the
equalizations of the ground potentials between the fuel pump nozzle and
the boat's bonding system.

It is recommended by ABYC and the USCG that new installations of this
type of fuel fill assembly DO NOT INCLUDE any attachment to the boats
bonding system. The U.S. Coast Guard and ABYC still require that
METALLIC body fuel fills be bonded. There have been no reported
explosions or fires resulting from this phenomenon. Therefore no
substantial risk of personal injury to the public exists, and formal
defect notification (recall) by boat and/or equipment manufacturers is
not required by the Coast Guard in this case. The ABYC Project
Technical Committee has included this topic in the soon to be published
H-24 Gasoline Fuel Systems on Boats that eliminates the bonding
connection for plastic body fuel fills with metallic caps and retaining
chains.