A ground installed refueling point, is more than likely grounded/ connected to an earth stake of some sort. I'm not familiar with them, and havent used one.
The Military (RAAF, USAF, probably RAF) systems I have used involve tankers.
The system taught has always been, that the aircraft when parked is connected to an earthing point (Brass head in the tarmac/concrete). The tanker when it arrives, will have an earth lead run out and connected to the same earth point on the ground. Another lead is run out and connected to the aircraft, usually near the filler point (winch may be a single fuel point connection or filler cap). After the hose is run out and before fueling, a bonding lead attached to the nozzle, is attached to a grounding/bonding point adjacent to the filler point.
Now, the aircraft, tanker and fuel hose are all at the same potential (nominally zero) and the potential for a static spark is pretty much eliminated. For everyone's information, . there is a tinned copper braided wire run down the length of the fuel hose, that clams to the nozzle , and the attachment point on the tanker. Continuity of this lead and the tanker earth leads are regularly checked for good continuity. (or should be).
The grounding/earthing point in the tarmac consists of a brass head attached to a copper coated steel rod about 1 meter long that is driven into the ground. resistance between the earthing points is measured after installation, and regularly (or should be, its a tedious job) and should be below 10000 ohms.
Here endeth the lesson...