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In article ,
says...
The earthling conductor is connected to the earth bar in the CU as it
should be. Should the outer steel armour be earthed?

The armour should be earthed at the house end.

There is no need for it to be connected at the garage end, provided some
other form of earth is used, such as an earth exported as a conductor within
the SWA (which appears to be the case here) or an earth rod.

Christian.

This is something which has long caused me some concern. If, for
example, the house is earthed by an earth rod (rural setting), and has
a phase to earth fault such that said fault is not sufficient to trip
the circuit's mcb, and is sufficient to bring the earth wiring, bonded
services and earth rod upto mains voltage - I've seen this happen -
then the swa gland at the remote building, if it's not bonded to the
remote building's "equipotential cage" will also rise to mains voltage
relative to the local earth.

Anyone touching the gland (albeit usually being sheathed) whilst
also touching a local earth, is in for a shock in more ways than one...

There are some circumstances (the one that I came across was
related to a LPG filling station) where it is required to utilise a
special type of swa gland, which incorporates an earth "break", such
that a sound mechanical joint can be made, whilst the earth continuety
is not. This means that since TT earthing is the only type allowed in
such installations, it is possible that full mains voltage could appear
across two potentially exposed conductors, very close together, which
in my book is more than hazardous...

--
Regards,

Will.