Bathroom light fitting bizarritude.

[Andy Wade]

there may be two neutral wires to one terminal of the lampholder. You might also find a 3rd terminal, not connected to the lamp, which serves as the live loop-in terminal (as top LH in your cited diagram).

To be expected. None of this is at all bizarre, it's all quite normal... honest.

[Andrew Gabriel]

Always make damn sure the third terminal is isolated and is not in fact an earth terminal connected to a metalic liner in the plastic baynet holder body. I have both types in my spares box. I even found one case of a 3-terminal baynet lampholder where the third terminal was labelled "loop" in the plastic molding, but was connected to the metalic liner.

[Andy Wade]

[Battenholders]

Ooh - I've never come across a battenholder where the third terminal was other than for loop-in. Usually there's a separate earth terminal in the pattress/base. Thanks for that warning.

[Mary Pegg]

't think so.

Looks like:

the batten holders it doesn't have nice sensible terminal blocks. Instead it's had two wires jammed into each of the terminals of the actual bulbholder bit.