Electricity cables in cavity next to door frame

[JohnW2]

The cable may be damaged during installation - Reg 522.8.1 refers

They may, just as they may when cables are installed in stud walls. In practice, probably very rarely an issue in either case.

The cable lacks support and also damage may occur due to the cable's own weight - Regulation 522.8.4 refers

True - but, again, equally true when cables are installed in stud walls. In practice, not an issue in either case

Thermoplastic insulation (PVC) in contact with polystyrene may cause the plasticizer within the insulation to migrate, leading to softening of the cable sheath - Regulation 522.5.3 refers.

True (in terms of expanded polystyrene). However, softening of the cable sheath is very unlikley to be a problem in relation to cable which will never move or be 'disturbed'

Cables installed within thermal insulation will have their current carrying capacity significantly reduced, which may require cable sizes to be increased - Regulation 523.7 refers

A valid point, which has already been made. As I've said, it's unlikely that anyone would manage to install a cable in a cavity that was already filled with insulation, but there will always be the risk that insulation may be injected into a cavity after a cable has been installed.

PVC cables are more prone to attract dampness

What does that mean? PVC cable are fine 'under water'.

The cable may be in contact with the outer and inner wall thereby providing a route for water

True - but, as I've said, equally true of the ties which are required to be installed between inner and outer leafs of the wall, not to mention the wast amount of rubbish often found in the cavity

.... Due to these reasons the installation of cables within cavity walls should be avoided.

That's a personal decision, but issue such as those mentioned above should be considered when making that decision.

 

[Murdochcat]

OK, but if i was the builder i would kick the sparky off site. There are lots of guide lines although not a rule, for good reason.
That is just laziness.

That’s hilarious.

A large percentage of builders think they are sparks and are responsible for such short cuts in the first place

 

[ericmark]

In the cavity of a cavity wall is over the 50 mm from surface, and if a cavity wall is filled with insulation, then it's not a cavity wall, there is no longer a cavity, simple English.

At one point it was common to run cables between floors in the cavity, and even when they started filling the cavity walls, they for a time continued to run cables in them. I remember trying to renew my sisters fuse box, and found the beads used in the cavity pouring out, had to drill holes, and put some glue above the unit to stop all the polystyrene balls running out. Around a 1985 new build.

The LABC are paid a lot of money to inspect building to ensure they are built as per spec. And there have been some extreme cases where they have clearly not done their job. Ruthin was the one I remember where foundations were a meter too low, so homes flooded before blocked culverts caused the water to flow over the road.

There was a long drawn out court case, the builder blamed the LABC for missing the error, and the LABC blamed the builder, never did read the final outcome.

However if the wires are wrong, then the question is who is at fault, builder, electrician, or LABC? And having been involved with errors where LABC were involved, not sure I would want to pursue them as once they get their teeth into things, they will not let go.

So the question is, if there is really a problem? Some times more prudent to turn a blind eye.

 

[EFLImpudence]

if a cavity wall is filled with insulation, then it's not a cavity wall, there is no longer a cavity,