Heres an idea... perhaps a little on the rough side though
Get a long thin drillbit (10mm dia should be big enough for your cable), and drill from the outside at such an angle that you come out in the corner, then chop the cable into the wall so that its within 150mm of the corner
You'll need cable-rods as well.
Get a long thin drillbit (10mm dia should be big enough for your cable), and drill from the outside at such an angle that you come out in the corner, then chop the cable into the wall so that its within 150mm of the corner
You'll need cable-rods as well.