Is This Compliant?

I assumed the tails are 16 mm twin and earth cable.

Nope Sparkingchip, just single insulated tails inside and outside the fuse box.

The whole installation used to be earthed onto the water pipe as far as we can tell. Ze was off the scale when tested. No R.C.D. Suspended wooden floor. New meter and isolator. Many circuits over fused. But no fires or shocks reported. TT earthed.

Now fully updated with a new consumer unit etc.

Z.

.

Single insulated tails connected up to new isolator.

The lack of mechanical protection of the old tails is causing exactly what problem Z? The meter installer (the DNO?) was obviously quite happy with them, why are you not, at worst a code 3? Tails are NOT double insulated as such, the sheath is mechanical protection and could be made of anything, say steel conduit as they often are in larger installations.

Though for an on an off-earth TT installation I think plastic trunking might have been a better suggestion, at least without an up front RCD. . Exposed basic insulation is not a great thing, but in places unlikely to be disturbed not a high risk.

The absence of an RCD and any reliable means of earthing is the C2..

M.

David Stone said:

The meter installer (the DNO?) was obviously quite happy with them

I am not sure about that. The bottom of the isolator is sealed, but the top is not. It may be that the supplier put in a new meter and isolator and left the rest to the householder.

What would be the difference between a 1 mm thick layer of brown PVC covered by 1 mm of grey, and a 2 mm thick layer of brown? So I don't think that those tails are intrinsically unsafe.

David Stone said:

The meter installer (the DNO?) was obviously quite happy with them

I am not sure about that. The bottom of the isolator is sealed, but the top is not. It may be that the supplier put in a new meter and isolator and left the rest to the householder.

What would be the difference between a 1 mm thick layer of brown PVC covered by 1 mm of grey, and a 2 mm thick layer of brown? So I don't think that those tails are intrinsically unsafe.

Chris Pearson said:

What would be the difference between a 1 mm thick layer of brown PVC covered by 1 mm of grey, and a 2 mm thick layer of brown?

One difference being that a nick under stress (e.g. at a bend) will tend to propagate, but will stop at the interface between the two layers. But for rigid undisturbed tails, it seems more of a theoretical consideration than a practical concern.