Over the last 12 months, Western Power has seen a positive and consistent improvement in the quality of construction for Underground Distribution Schemes. The last 5 months have seen consistently better than 80% compliance. While the majority of the non-conformances present medium to low risks, there has been a concerning trend in the substandard installation of live end seals (LES) for working ends which represents a high risk to the safety of the network.
The issues referred to in this bulletin have been identified specifically in externally constructed projects. These substandard installations have insufficient protection and are not being identified in line with Western Power requirements. Variable cable depths have also been noted in some instances.
Since 4 July 2016 Building and Energy and Western Power require that all cables for future use in subdivisions be terminated into a LES and buried.
The Underground Distribution Scheme (UDS) manual 188.8.131.52 stipulates where live end seals should be used and points to the relevant construction standards.
The construction standards are defined in the Distribution Construction Standards Handbook (DCSH) R34-1 and R34-2. The construction standards must be followed when installing a live end seal. The standards indicate required depth, mechanical protection, location, identification markers and backfill requirements.
General cable installation requirements are indicated in Section 14 of the Underground Cable Installation Manual (UCIM).
The photographs below indicate the correct installation and as-constructed photographic evidence for the installation and handover of the LES.