Cable size when burying

[craig.jones76]

I have a run of cable where 12% is buried in ducts, the rest is on perforated tray, what are the limits on amount of cable buried when sizing cables?

 

[pc1966]

Also check what the OCPD requirements are, it might be each charger needs its own protection so you would be needing either 6 cables from the DB, one per charger, or a sub-DB at the end to distribute power.

I am no expert on EV chargers but I would be very surprised if 22kW units are not 3-phase, and also need neutral, so you would be looking at 4C cable for the feeds.

Also are the two cables you mention going in separate ducts, or shared duct? Then you have to allow a grouping factor as well as the buried-method de-rating.

 

[timhoward]

I am no expert on EV chargers but I would be very surprised if 22kW units are not 3-phase, and also need neutral, so you would be looking at 4C cable for the feeds.

Yes, 22Kw EV charge points are 3 phase. The only one I've seen in the flesh required a neutral.
I almost mentioned the 4th core but thought there was a remote possibility these were DC chargers as 6 of them sounded like a large car park where rapid charging might be required and it would begin to explain the larger cables.

 

[craig.jones76]

Also check what the OCPD requirements are, it might be each charger needs its own protection so you would be needing either 6 cables from the DB, one per charger, or a sub-DB at the end to distribute power.

I am no expert on EV chargers but I would be very surprised if 22kW units are not 3-phase, and also need neutral, so you would be looking at 4C cable for the feeds.

Also are the two cables you mention going in separate ducts, or shared duct? Then you have to allow a grouping factor as well as the buried-method de-rating.

HI

Cables will do into conduit under the ground and be grouped together.
The chargers are 415V, no mention of neutral on data sheet but I'll check with supplier.