Mike Tomlinson wrote:

... This is an important principle of the UK wiring code. It's
referred to as "equipotential bonding."

I wonder if "ring mains" (an extra wire from the last outlet to make
a loop back to the fusebox) are legal in the US. Seems like a nice way
to improve voltage regulation with a little extra wire, and if the ring
wire only breaks in one place, all the outlets keep working.

Nick