Maintenance holes and cable trunking systems are usually fabricated on site or supplied as precast reinforced structures.

Maintenance (or access) holes and cable trunking runs are enclosed with access covers arranged in a multipart or trench run configuration. These enclosures are large reinforced concrete structures, sized according to the cable arrangement and may also be used to cater for the co-existence of other services/utilities or house equipment.

The design of these underground spaces is bound by the wiring rules set out in AS/ACIF S009. AS/NZS 3084 also offers some basic guidelines.