Utilities in the cavity

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With my trusty endoscope I am able to look in much more details at the issues with the bodged insulation.
It's pretty clear that the wall that is suffering the most from damp is is poorly filled with variable density fill and some large voids and bridging mortar.
However, not all cavity obstructions are brick/mortar. I have a certificate which proves that the electrics were rewired 4 years prior to the cavity insulation and the electrician decided to use our narrow cavity as a conduit as seen in the photo below.
The cavity is so narrow that the insulation filling has been stopped by the wires, leaving a large void running up the wall. Some parts of the wires are completely encased in insulation.

As far as the CWI is concerned this is a pre-existing obstruction and bridging of the cavity which should have been picked up on a pre assessment. The size of the void makes this insulation in-compliant to the BBA certificate.
A pre existing damp problem caused by the electrics or presence of a large obstruction in the cavity should stop a CWI installation at the assessment of the cavity. These wires are not subtle - it would have been spotted by looking into the wall with a borescope at any of the drill holes.

Things brings up some interesting questions.
Now putting wires in cavities is not the best idea but is 'undesirable' rather than against the building regs.

BS 7671, The Building Regulations 2000 for England and Wales (2004 edition) and Mandatory Standard 3.10 of the Scottish Building Regulations highlight a number of reasons why this practice is undesirable:
  • The cable may be damaged during installation - Reg 522.8.1 refers
  • The cable lacks support and also damage may occur due to the cable's own weight - Regulation 522.8.4 refers
  • 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
  • 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
  • The cable may be in contact with the outer and inner wall thereby providing a route for water - Approved Document C Building Regulations
  • A route for precipitation might be provided where a hole exists from the outer wall - Mandatory standard 3.10 Scottish Building Regulations
So what that says is that Polystyrene beads should never be in contact with electrical wires and if retrospectively installing cavity wall insulation the cable size may need to be increased to be in line with 7671.

 Clearly in a narrow cavity; electrics can impact filling and violate the BBA certificate requirement for required density and R value. More evidence that no pre assessment survey was undertaken,

 The Building regulations are a bit more clear
BS 8208 Part 1, 1985: Assessment of suitability of external cavity walls for filling with thermal insulants. "Where they cross the cavity. Cables may need moving or uprating before a cavity is filled (they can overheat if surrounded by insulation)."

 So again, CWI should never have proceeded with this problem. It's worth mentioning that the CIGA inspector drilled a hole inches away from these live wires and risked electrocuting himself.

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