Use of Aluminium Wire Armour for Single Core Cables

Dunno. Why don't you tell us.

Aluminium is non-magnetic. Hence, there would not be any induced currents in the armour due to the current flowing in the main conductor.

ok, but y we are using it in single core cable particularly.

Dunno. Why don't you tell us?

in a single core cable steel or any magnetic material is not used for armor for reason already mentioned in earlier responses.
a good reading is suggested for the differences between aluminum and steel armor in cables in general for all - - -
http://www.anixter.com/AXECOM/AXEDocLib.nsf/(UnID)/14FA0C8C75D8006B80256F24006E59F4/$file/a-2_2.pdf

Some of the explanations here are sound, but not entirely accurate. My organization has used steel armored cable for multipair and coaxial systems for nearly 50 years. These systems are both high and low voltage systems (many miles in length) transoceanic cable systems designed by AT&T, Lucent, etc.

What about single core, though, like the original poster?

Single core as in coaxial? Then, yes. I have several list versions of the cable each utilizing various layers of steel armor. We also have a complex grounding system which includes the armor layer.

single core as in single core . . . no more no less . . .

For the same reason mentioned above, apart from armour, anything 1C cable passes through like gland plate, metallic conduits etc. should also be of non magnetic material.

Not sure where you are going with this...single core cable as in...? Coaxial is a single "core" cable with a shield. I guess that you (and the OP) mean power cable, not signal cable.

Guess I should have picked up on that.

Good responses already. You may also want to avoid steel cable trays and cable ties in such an application and preferably arrange the cables in a trefoil.

steel trays may be acceptable if the magnetic math does not close around the conductor.

i believe maxwell, faraday, lenz and a host of others worked hard enough to tell us that we must not allow a closed magnetic path around a net non zero current unless we want to build an electromagnetic machine for transferring or converting energy.