Dave wrote:
I've recently refitted a Mira Event Power Shower after retiling the
shower cubicle. I've also fitted a new shower head and hose of a metal
type. The one originally supplied with the shower was plastic.
Everything seemed to be fine for a week after the shower was put back
into action but now there is a slight electrical shock when standing
in the shower and touching the shower hose, and only when the shower
pump is running. (I've now isolated the shower until it's resolved).
Does anyone know if showers of this type should always be fitted with
a plastic hose and shower head? The earth connection from the fused
spur feeding the shower unit is connected but there is no way to cross
bond the metal shower hose as the inlet and outlet connections for the
water are all plastic.

You may need to bond from the mixer valve to the nearest metal pipework or main
earth terminal in the fuse box. Because the pump is more likely using an
induction motor, there will be leakage to earth through its casing, so this
needs to be dealt with before the problem goes away.

Maybe that's why the shower had a rubber hose fitted and the plumber or sparks
couldn't find anything nearby to bond on to.