Car Charge Points

[Barx]

Car Charging points:
I've not really dealt with them to be honest but have some drawings for new builds and designer wants a 13a single socket outlet installing outside for car charging. From what I see this will allow for mode 1 or 2 charging. No problem.

New build so supplies are TNC-S (confirmed). Now I was previously under the impression that a charge point fitted outside on a TNC-S system must be TT'd??? This is not in the design. This is just connected to MET and a rotary iso used for isolation.

I've checked regs (and this is also quoted in CoP, reg 722.411.4.1 shows exceptions to when charge point can use TNC-S earth and although any of the 3 points aren't likely to be possible, it also states that the reg need not be applied in dwellings. Does this mean that it is fine to use the TNC-S earth if the point is on (out side wall) of a dwelling?

Struggling to find a definitive answer and don't want to agree to do it if it's wrong.

Cheers

 

[Andy™]

you can charge from a 13a socket, but the proper charge points would be 16 or 32a. you can get 63 & higher but ive not seen any of these in a house

last time i fitted one (commercial) on a TNCS, i fitted a rod and isolated the TNCS earth

but if its just a 13a socket he wants, then its just a socket, no different to any other

 

[Murdoch]

I would just fit an IP rated socket.................

 

[apprentice87]

Just an observation, as i know nothing about electric cars or charging them..

Ok, say the socket supplies 10A [any more and it will over heat] say you let it charge for ten hours, would this not be about enough power to push a moped about the next day.. cannot see you would get much use out of your car..

john..

 

[Evans Electric]

I tend to agree with  Murdo  ....price it up following the design .   Perhaps consider the  outside socket on a radial?   Outside sockets use the  TNC-S  earth .    

I learned on here that the cars  have the charger built into the vehicle ..not ..as I thought ,  a separate charger like a fork lift truck.

I have no idea if a 13A  supply is enough to re-charge an electric car overnight   TBH.  

 

[Andy™]

cars do have their own charger. the lead is also capable of 63a TP. the controller in the charge point tells charger in the car what power is available

 

[Murdoch]

There tend to be 3 ratings of car chargers offered by specialist companies

13A

16A

32A

I'm running in a cable whilst an extension is being built - I've used 6mm so they can install a top rate charger if they want later.

IMHO theres no point in a 13A charger for a car...........................

As for the earthing - now which way is the wind blowing now?

 

[Ardet R]

Electric vehicle charge points are a bit of a nightmare when it comes to earthing as the IET is being inconsistent and or ridiculous.

I think there was a wiring matters article after the initial COP came out (with its wildly ridiculous requirements; all conductive parts separated by 10m (bigger than a small house), TT the whole installation, etc.!) that said the IET do not know the risks so they are getting an assessment done, I never heard the outcome of that but the next edition of the charging points included the provisions for, again totally unrealistic scenarios for existing domestic installation, the conditions under which a PME earth could be used but provided the exclusion for a domestic charging point for a single family domestic property if the other three conditions could not be practically met.

At present, until the 18th comes out, I think that it is possible to use the PME earth for a car charging point on a single domestic dwelling if the three provisions cannot be practically met.  Though on a new build it should be possible to install an earth electrode(s) connected to the MET with a resistance of less than 1Ω, with a certain amount of effort, and then condition ii) would have been met and the PME earth can be used with impunity.  It would be up to the designers to be able to argue that installing an earthing system whilst building was not possible.

The summary I wrote for myself on this one was:

Outdoor charging:  No PME except

i)             3~ multi use loads MET – Earth on OC PEN <70V

ii)            Electrode with bonding sized Earth condcutor and on OC PEN <70Vrms

iii)           CPC – E >70V ADS <=5s, manual reclose (no product standard yet)
Needs Electrode out of other earth influences!

But if a dwelling (1 household) not applicable if not reasonably practicable.

 

[Evans Electric]

This business seems to sum up what this country is like these days ....no one will  stick their head over the parapet ...make a decision ...like Bloody Brexit .

 

[Murdoch]

Electric vehicle charge points are a bit of a nightmare when it comes to earthing as the IET is being inconsistent and or ridiculous.

I don't think they know what they are doing or suggesting - BS 7671 is rapidly turning into a book like the bible - written by many people with different memories and views on things .......

earth rods for all TNCS installs anyone?

 

[apprentice87]

earth rods for all TNCS installs anyone?

Cannot be a bad thing.. [especially as now many places do not have incoming metal services to bond to]

Got to laugh about "perceived shock".. It is not "perceived shock" at all, you HAVE had a shock due to the ****ty cheap and nasty TNCS...

john..

 

[Andy™]

earth rods for all TNCS installs anyone?

hasnt made it to 18th. might be in a future amd or edition though

 

[binky]

I wouldn't install a rod for an external socket fixed to wall of house with TN-C-S, so I don't see why a charger point would need a rod. If the charge point was away from the building, then maybe TT is the way to go, same as exporting earthing to a garage from a TN-C-S house

 

[Sidewinder]

hasnt made it to 18th. might be in a future amd or edition though

Will be in amendment 1

 

[Sharpend]

- BS 7671 is rapidly turning into a book like the bible - written by many people with different memories and views on things .......

Only it will not be as accurate. 

 

[Murdoch]

Will be in amendment 1

I simply can’t wait until I have to attempt to put a rod in for a 5th floor flat ......

 

[Sidewinder]

I simply can’t wait until I have to attempt to put a rod in for a 5th floor flat ......

Yeah as usual they haven’t even thought of that.

Also the DPC stage is already over!

The BSI site was giving problems during most of the period.

Was there an extension.

No.

Democracy at its best, not.

 

[Murdoch]

Yeah as usual they haven’t even thought of that.

Also the DPC stage is already over!

The BSI site was giving problems during most of the period.

Was there an extension.

No.

Democracy at its best, not.

Its farcical regs like this that completely undermine the authority of BS 7671 and the IET...............

 

[Tony S]

Yeah as usual they haven’t even thought of that.

Also the DPC stage is already over!

The BSI site was giving problems during most of the period.

Was there an extension.

No.

Democracy at its best, not.

I thought the earth electrode requirement was dropped ? ? ? ?

 

[binky]

Lord knows, I haven't read the bumpf for a while, but in short it's just basic electrics made complicated by regs.