Not if you want to comply with BS 7671:2018+A2:2022

I guess one worry is that a broken PEN doesn't necessarily effect just a single installation - even if your installation is perfectly balanced with zero N current, the supply CNE could still be a long way from true Earth potential - due to connected loads in neighbouring installations, if the LV network is shared.

    - Andy.

We do get a TN-S when possible, saves all the maths and a bit of money. 

This is always the worry when not coming direct from the transformer and knowing what is connected to neighbouring supplies would be impossible to ascertain. 

I am only asking about it as we are now have a new rapid DC charger in our portfolio which doesn't require the neutral so I was hoping we might be able to simplify the installation. 

The other chargers we use all require neutrals and are not balanced and/or have both mode 3 & 4 so its not really been considered before. 

Thank you for all your input.

It is a bit of an academic diversion, but you could have 3 heaters wired either star or delta, so the line load is equal on all 3, and the suppy neutral could then be removed.

With a charger that supplies the car with DC this is likley to remain true, however, it would be a brave person that said that all cars that take 3 phases will always be  internally that well balanced when throwing around the fat end of 100A per phase. If it was a simple 6 diode bridge, and all cables were lovingly matched, maybe, but it is likely that in the 3 phase to the car case there is an array of six or 12 switching transistors and a very complex control algorithm to pulse modulate the conduction waveforms..

Mark Fleming said:

The chargers themselves only require 3 phase & earth

So there is no neutral to lose.

note that no neutral does not always mean all 3 line currents are balanced, you can have a delta of 3 different resistances,  3 different line currents, and no neutral current, so if the PEN goes O/C there is no ground pull.

Mike.

Chris Pearson said:

So there is no neutral to lose.

Not quite - the Neutral may be there to provide the PE at the service head.

However, in this case, OP has confirmed they are likely to use the N of the TPN for small single-phase loads at least (anti-condensation heaters)

Yes, I noticed that, but if it isn't part of the charger, does it matter?

Is that likely within the chargers themselves? My first thought was that by no means all cars can draw 3 phases, but then I realised that the chargers are DC so unless they became faulty, how would an imbalance arise?

I noticed that, but if it isn't part of the charger, does it matter?

In the case of an open PEN event, the heater will pull the severed N/PE/installation metalwork up to the voltage of whichever line it's connected to. If there's no EV on charge at that moment (or the charger is only connected L-L-L), there's no (balanced) load that would create an artificial star point and  keep the N (& installation's PE) nearer zero.

   - Andy.