What is SWA cable for an outdoor charger supply?

SWA means steel wire armoured cable: insulated conductors protected by steel wire armour and an outer sheath [S1]. It can form part of an outdoor charger supply, but the route and electrical design determine suitability. The IET explains that Regulation 522.8.10 requires burial deep enough to avoid foreseeable ground disturbance, rather than one universal depth [S2]. Checked October 2026.

Last checked 19 October 2026

What does SWA cable mean for your site?

SWA is steel wire armoured cable, with insulated conductors, steel wire armour and an outer sheath. The armour provides mechanical protection, but does not make every cable arrangement suitable for every location [S1].

For your site, the important point is that an outdoor charger supply is a designed cable route, rather than just a length of cable. Ask the installer to show the route from the distribution board to the charging equipment. Use cable runs and groundwork costs for the excavation scope.

How do the route and charger load affect sizing?

The IET distinguishes maximum demand, distribution equipment and final-circuit conductor selection. It also explains why earth fault loop calculations can matter on long SWA runs [S3]. A cable size copied from another site therefore does not establish suitability for yours.

Ask for the design load, route length, installation method and protective arrangement in the proposal. If you expect more chargers later, request a separately stated expansion design. Keep that discussion alongside your site power assessment.

How deep should the supply cable be buried?

There is no single depth suitable for every business site. The IET explains Regulation 522.8.10 through foreseeable disturbance: cultivation, vehicle activity and other land uses change the risk [S2]. Request a route-specific specification, including protection and reinstatement, before agreeing excavation work.

For the budget, ask for cable, terminations, trenching, surface repairs and service-location work as distinct items. This is a scope checklist, not a price estimate. Retain the completed route drawing with your installation records. Use the charging cost tool separately for electricity use.

Next step

Mark your proposed bays and supply route in the site check, then get matched with an installer that covers your area.

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