What Ducting Is
Ducting is the use of protective conduits or ducts to route and shield electrical and communication cables. In EV charging installations, ducting provides a safe pathway for power feeders and data lines between the supply point (switchgear/DB) and chargers, often underground or within buildings.
Ducting can be single conduits for one cable run or part of a larger grouped system like duct banks.
Why Ducting Matters for EV Charging
Ducting is a core part of reliable, maintainable charging infrastructure:
– Protects cables from mechanical damage, moisture exposure, and soil movement
– Reduces fault risk and improves long-term reliability
– Makes future upgrades easier (pull new cables without re-trenching)
– Supports cleaner installations and clearer separation of power vs comms
– Helps meet electrical code requirements for cable protection and routing
Where Ducting Is Used
– Underground runs across car parks, depots, and driveways
– Under roads or sidewalks (often with directional drilling)
– Inside buildings: risers, garages, plant rooms, and cable trays
– Between DBs and charger pedestals, islands, or wall mounts
– Site expansions: spare ducts installed early for future bays
Common Types of Ducting
– PVC conduit: common for building interiors and some underground use
– HDPE duct: common for underground routes, flexible and durable
– Steel conduit: used where high mechanical protection is required
– Concrete-encased ducts: used under roads or high-load areas
– Cable trays/ladder racks: above-ground containment in industrial interiors
Key Design Considerations
Good ducting design reduces future cost and prevents installation failures:
– Correct duct diameter for cable OD, pulling, and spare capacity
– Bend radius and route smoothness (tight bends are a common failure point)
– Access points: pull pits/handholes for long runs
– Separation of power vs data ducts where required
– Proper depth, cover, and warning tape for buried ducts
– Water and silt control: sealing, slope, and drainage approaches
– Planning for expansion: include spare ducts and oversized routes where sensible
Common Pitfalls
– Ducts too small → cables cannot be pulled or overheat
– Too many bends/no access pits → cable pulling fails or damages insulation
– Poor sealing → water ingress and blocked ducts over time
– No as-built documentation → future expansion becomes slow and risky
– Ignoring thermal derating when multiple heavily loaded power cables share a route
– Mixing comms and power without separation → interference and compliance issues
Related Terms for Internal Linking
– Duct banks
– Cable ducting
– Directional drilling
– Civil works
– Distribution boards
– Cable pulling tension
– Site reinstatement