Dolphin shower installed in 2000.

The ‘dark grey’ sheathed cable that's still connected?

Any more clues - e.g. what's it connected to on the shower itself? A special pair(?) of terminals or one of the ordinary ones?

   - Andy.

That's it the dark grey cable. 

It Bod is about later we may get a comment on the earthing arrangement, which has a separate earth conductor running back to the fuse board as well as the local equipotential bonding, any one else care to comment on that as well?

It is not RCD protected ?

I still can't see where it goes ?

Other possibility is that it's part of a load shedding system (feeds back to a relay to turn something off else when the shower is on (or disable the shower when something else is on))

I'd missed the Earthing arrangement - I thought it looked like a sheathed c.p.c. from the T&E plus two supplementary bonds.

   - Andy.

The long thin ceramic rectangle near the inlet valve looks like an add-on resistor. Is it in a location where freezing up is an issue  ?  If so perhaps a frost stat ?  Is it just one core or a multicore ? Clearer pics or description needed.

Looks like it may be the 860 ?  if so the heater is 'direct to water' rather than an immersion type, hence all the extra earthing, and you cannot have an RCD.
 

Mike.

@mapj1 is on the same wave length, I trained as an electrician around the time this shower was installed twenty one years ago and have never actually installed one of these myself as they were becoming obsolete at that time.

I think it is an uninsulated water heater, but presumably it has been okay for over twenty years and has not killed anyone.

Apparently this is the only circuit and appliance in the house that is not RCD protected and is supplied from a one way fuse board next to the consumer unit.

They used to do one where the element was a “long spring” inside a perspex block that the water flowed thru. The switches (left and right)  operated a cord pulled toggle switch hidden inside the unit

I should have asked the plumber to hang onto the shower, I presume the spring element in a Perspex tube is what can be seen under the metal bar with the labels on it.

With the water flowing in at the 230 V  end of the uninsulated element and out at the nominal 0 V neutral end………

Regards

BOD

However, note the length of the hot water “output” pipe and the earth connection on the union where the shower hose connects! 

Regards,

Alan.