Being floor heating wire,
I would guess there is a leak somwwhere,
lets assume for now,
that there is a leak between two adjacent
lines in the concrete slab, lets say there half a meter apart.
There would be a voltage potential across these two spots.
If the floor was damp and some one stood across these two spots
depending on the exact circumstances you could get a zapp !
chances are low,
But still possible !
And a lot of people dont like even small risks !
Especially government departments.
like hospitals schools etc.