Underground Cable Route to device which needs TT-ing

Matt_M · Mar 9, 2014

Hi guys,

I have a bit of a quandary about an installation I have coming up; I need to install a 100kW rated Electric Vehicle charging station in the middle of a car park.

The supply (PME) will be in a toilet block building approximately 45m from the final location of the charger. There will be a 125mm duct installed 600mm underground with warning tape 150mm above it. The charger itself will be isolated from the PME supply and earthed to a Mat-lattice.

The charging station itself is metallic framed and the cable entry point is dead centre on the bottom of the unit. There is no way of terminating a SWA and even if i could fabricate a bracket for terminating a SWA into, the PME would be exported due to the metallic case of the charger.

So, my question is, how would you get a supply out there? I have come up with a couple of options and am interested to hear thoughts and suggestions:

1) I run a SWA cable (or dual supplies to reduce cable size) and use heat-shrink at the charger end to terminate the cable (not right keen on terminating a cable like this)
2) I use something like a H07RN cable (i'm not right keen on putting a cable underground without armoured protection) but it will be easier to pull and terminate

Thanks in advance,

Matt

Plonker 3 · Mar 9, 2014

Could you not install ducting upto the underside of the charging unit, then use a stuffing gland on a cable?

shanky887614 · Mar 9, 2014

Why not terminate into an isolator (locked on of course)

Then from isolator to charging station.

You could then gland from isolator to charging point without connecting the armour from isolator to charging point

Using 3/4/5 core

Matt_M · Mar 9, 2014

I will be probably be able to use a stuffing gland. The cable size required is 95mm so it wont be right easy.

I guess i could use 2x 25mm SWA and run them through stuffing glands on the bottom of the unit?