Door Bell Transformer

[zerobug]

I hoped someone might advise please: I'm replacing my ancient ( probably 40+ yrs old ) door bell transformer with a British General unit mounted in a Wylex housing, fed via a switched fused spur. The previous unit had a switch only, it was fused at the consumer unit connected into a lighting circuit.
My question is: that the previous transformer had an earth connected to the low voltage side of the circuit, is this required, should the same arrangement apply for the new transformer? It seemed a bit unusual, but must have been added to the existing old transformer some years ago when a rewire was done. Thanks for any advice.

 

[brianmoooore]

Unless there is a terminal on the new Tx marked earth (which I doubt, then no earth connection should be made.
The new transformer will be an isolating Tx, where there is no danger of any leakage from the primary side to the secondary side. This is achieved either by a metal shield between the two windings, which must be earthed, but does not connect electrically to either winding, or by placing the two windings on different legs of the transformer frame.