Commercial and industrial — EV Charging Installation Practice

Sample questions

1. 01A workplace has a three-phase supply. L1 already carries the kitchen, and L2 and L3 are lightly loaded. Six single-phase 7 kW points are to be added. What is the best starting design?

   • APut all six on one circuit from a 63 A three-phase device
   • BSpread the points to suit the existing load on each phase
   • CPut two points on each phase, ignoring the kitchen load
   • DPut all six points on L1, so the kitchen and EVs share it

   Why: Single-phase points are spread across the phases taking account of what is already on each one, so L2 and L3 take more of them. Two per phase balances only the new load and leaves L1 the heaviest. Each charging point needs its own final circuit (722.533.101), so one shared circuit is wrong whatever the device, and Annex A722.1 reminds you that neutral current peaks at maximum imbalance.

2. 02A load management system keeps eight workplace charge points within the rating of their distribution board. What does Regulation 536.4.202 require of that board?

   • AIts rating must cover all eight points at full current at once
   • BIt needs no rating check, as the load system protects it
   • CIt may be rated for half of the total by applying diversity
   • DIt must be rated for at least the limited maximum demand

   Why: Where load curtailment limits the maximum current demand for an assembly, 536.4.202 says the rated current of the assembly and any outgoing unit shall be at least the limited maximum demand. Rating for all eight at full current is not required, diversity shall not be used as load curtailment or overload protection, and the board still needs a rating check.

3. 03An employer buys a 7 kW charge point for a staff-only car park at its factory. Are the Smart Charge Points Regulations relevant to that unit?

   • ANo, a business owns it, so it counts as a public point
   • BNo, the Regulations cover home charge points and nothing else
   • CNo, only rapid charge points of 50 kW or more are covered
   • DYes, a workplace charge point is a private point in scope

   Why: Regulation 3(3)(g) defines a workplace charge point as one intended for use by people at their place of employment, and the OPSS guide treats workplace points as private, so they are in scope. Business ownership does not make a point public; public means intended primarily for members of the general public. Rapid points of 50 kW or more are excluded, not the only ones covered.