In article , Alan
scribeth thus
On Tue, 07 May 2019 08:39:55 -0700, spuorgelgoog wrote:

I'm not sure you can either, but the Wiring Regs committee hope that
someone will make them fairly soon.

The answer seems to be electric vehicle charging points in single-phase
PEN installation.

722.411.4.1(iii)

The main earth terminal is connected to a an earth electrode and again
in the event of a break of the incoming PEN conductor the voltage
between the main earth terminal and the earth does not exceed 70 V.


I think that means you need to ensure an earth rod is of a sufficiently
low impedance to earth, to not permit a rise of voltage to 70volts. And
that is in the case of a break in the Suppliers cable.
VOELCB are not currently available, and unlikely to be in the future.

So we have a house and out in the driveway there is a charging point
thats off the typical main house 100 amp incomer?.

Which if its going to be a rapid charger won't be enough capacity
assuming the house is pulling its likely max load. _If_ used in the day
time.

So then we either have to provide another "House" worth of supply
presumably another phase or we beef up the main incomer to say 200 amps
now which is going to be a massive undertaking?. Lots of road digging
and new big 'eff off size substations?

Well OK this is a new ball game and may not be the best option it will
be a very expensive one for the local power supply co.

But lets assume that we are now going the use a "trickle" overnight
charger system which I think will be the option to use and unless we
have a house with that useless night storage heating that may be
pulling more amps and not enough for the vehicle charger??

So assume that we now do this overnight and we have and option to take
this off the main distribution board and that will make some demand I
suppose what 30 to 50 amps? Whatever?

Well in practice would there not be a MCB rated at say 40 or 50 amps and
a separate RCD. So if the earth conductor comes undone the leakage of
any capacitors used in the charger may be transferred to the car body?

So the whole car may now assuming the power carrying cable to the car
has a protective earth that carried in the connecting cable from the
charger.

So are we saying that under this scenario the leakage voltage WRT earth
of the car must not rise to above say 70 volts then?

Is that what's meant??

--
Tony Sayer


Man is least himself when he talks in his own person.

Give him a keyboard, and he will reveal himself.