Closed loop embedded in a concrete wall

[invalid@xxxxxxxxxxxx (Beachcomber)]

I will have access to a concrete foundation wall space before the pour
and I would like to embed a simple closed loop trip circuit to deter
against the remote possiblity of a break in from the basement.  (This
is a commercial installation.  The wall will be at least 8" thick and
have rebar inside for strength.

What type of wire/cable would be best?

Here are my concerns.

I don't want to use bare copper in the concrete because of
oxidation/deterioration concerns and the possiblility of accidental
grounds.

The wire or cable should be mechanically thick enough to last a long
time (many many years), but readily break if the wall is attacked with
drilling, sledge hammers, etc.

What materials would be best for concrete?  Would you use a plastic or
metallic sheath? ...Possibly PVC?

Any suggestions or advice would be greatly appreciated.

Beachcomber