Q & A of the Day – Should diversity be allowed for in supplying these garages with EV charging points?

 

Question: I’ve been asked to quote to supply an existing block of 49 garages at a large block of flats with distribution cabling and switchgear to provide sufficient capacity for a 7kW fast charging point in each garage, along with power for lighting and electric garage doors. 

 

I assume that diversity must be allowed for, as otherwise a 600A three-phase supply would be required. What should I do?

 

Please can you assist, as I can't find any published data. 

 

Answer: This is a good question, and one that has major implications for infrastructure associated with the introduction of electric vehicles?

 

The latest amendment of the IEE Regulations, BS7671:2008, issued in August 2013, covers the requirements for electric vehicle charging installations. Section 722.311 is the relevant clause, which states that: 'A dedicated final circuit shall be provided for the connection to electric vehicles. It shall be considered that in normal use, each single connecting point is used at its rated current. Where the final circuit supplies more than one connecting joint, no diversity shall be allowed.? Diversity may be allowed for a dedicated distribution circuit supplying multiple electric vehicle connecting points if load control is available.'

 

The amendment can be downloaded from the IET website – but please note that there may be a charge payable. Go to: http://www.theiet.org/resources/wiring-regulations/index.cfm

 

Unless load control is applied for the proposed installation, then adequate provision for the chargers should be provided.