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Discuss Electrical car charging point installation in the Electric Vehicles Advice Forum area at ElectriciansForums.net

Midwest

Midwest

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Esteemed
Arms
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Did you mean to write more rather than just '1'?
I think possibly a tutor would have written an explanation for each of the 3 questions, not just written '1'. :D
Think his reply is within the 'quote box', and I'm no expert but I don't agree with his answer for 3.
 
Aico 3000
E

Ed Evans

Did you mean to write more rather than just '1'?
I think possibly a tutor would have written an explanation for each of the 3 questions, not just written '1'. :D
read the next bit
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Think his reply is within the 'quote box', and I'm no expert but I don't agree with his answer for 3.
yes your are right you are not an expert or even picking up that more information is required to give accurate and correct information.
 
Midwest

Midwest

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Esteemed
Arms
read the next bit
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yes your are right you are not an expert or even picking up that more information is required to give accurate and correct information.
Thats a bit harsh?

You said;

'If the charge point is in a garage that is attached to the building it does not need to be "tt'D" if it is not attached it then needs to be made into a "TT" system''.

Thats, if I recall, is not what is exactly said in Section 722.
 
happyhippydad

happyhippydad

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Esteemed
Arms
  • Thread Starter Thread Starter
  • #16
read the next bit
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yes your are right you are not an expert or even picking up that more information is required to give accurate and correct information.
When I was teaching Maths many moons ago I don't think I would have ever responded to a pupil like that. It would not have aided in their learning, it would just embarrass them and stop them from asking questions again.
Ps. Thankyou for taking the time to offer suggestions to my questions though.
 
J

Julie.

Esteemed
Arms
My take on the answers are
1. Has to be on a dedicated circuit?

Not mandatory, but makes sense much more than any general circuit

2. Has to have Type A RCD protection.

Sort of! The output must be protected by type A - PLUS 6mA DC protection, (or type B as an alternative), often this is included within the charge point, so swa and mcb protection can be used on the supply to the charge point.


3. PME cannot be used if the charging point is located outdoors, therefore has to be TT'd?

In my opinion - yes, but the standards do allow the use of the pme earth if you utilise special devices to identify a lost pen/CNE; if these are within the charge point, then ok, although I don't believe they actually provide the protection needed for safety - but as the manufacturers have pressurised the committee to accept them, and it's in the spec (amd 1) then you could use them.
 
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Midwest

Midwest

-
Esteemed
Arms
My neighbour had his car charger fitted this week (PME supply). As far as my nosey neighbour goggles tell me, there's no obvious signs of a rod. Can't quite make out the make of the box of tricks, but the stress is getting to me. Might just ask him outright. :)
 
E

Ed Evans

Thats a bit harsh?

You said;

'If the charge point is in a garage that is attached to the building it does not need to be "tt'D" if it is not attached it then needs to be made into a "TT" system''.

Thats, if I recall, is not what is exactly said in Section 722.
The 18th Edition amendment does say this. When i delivered the course 2 weeks ago this was discussed at length because when it is made into a "TT" system the swa if it is used, will have the armouring earthed at the domestic consumer unit but not attached as an earth at the EV charge unit. You then use the earth rod, if you are using one for an earth, for the EV charge point system in the garage. Also it must not be possible to simultaneously touch the house extraneous conductive parts and those of the garage as if they are at a different potential we all know what could happen.
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I can’t seem to find a recent thread on car charging/PME supply, which had all the discussion about PME supply, so resurfaced this one (bet someone will find it now).

What makes of charges use a system that completely isolates the car from the supply?

Neighbours just got an electric car. So wanna be a smart arse before he has the charger installed.
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I’ve just googled the vehicle. £72,000. Doesn’t include the charger, nor a sunroof. Perhaps it’s got PV on the roof?
Isolation from the supply can be achieved by using an isolation transformer. But it is still fed from the house originally. Or a PV array but the charging will take a lot longer.
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When I was teaching Maths many moons ago I don't think I would have ever responded to a pupil like that. It would not have aided in their learning, it would just embarrass them and stop them from asking questions again.
Ps. Thankyou for taking the time to offer suggestions to my questions though.
no problem
 
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Midwest

Midwest

-
Esteemed
Arms
The 18th Edition amendment does say this. When i delivered the course 2 weeks ago this was discussed at length because when it is made into a "TT" system the swa if it is used, will have the armouring earthed at the domestic consumer unit but not attached as an earth at the EV charge unit. You then use the earth rod, if you are using one for an earth, for the EV charge point system in the garage. Also it must not be possible to simultaneously touch the house extraneous conductive parts and those of the garage as if they are at a different potential we all know what could happen.
Post automatically merged:


Isolation from the supply can be achieved by using an isolation transformer. But it is still fed from the house originally. Or a PV array but the charging will take a lot longer.
Post automatically merged:


no problem
But it does not mention ‘an attached garage’ or ‘not attached’.

It says (paraphrasing slightly),

‘PME earthing facility shall not be used as the means of earthing for the protective conductor contact of a car charging point located outdoors or that might be reasonably expected to be used to charge a vehicle located outdoors, unless one of the following methods is used;’ (722.411.4.1)

A subtle difference, do you not agree?

I‘ve not seen an isolating transformer for a car charger just yet.
 
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J

Julie.

Esteemed
Arms
But it does not mention ‘an attached garage’ or ‘not attached’.

It says (paraphrasing slightly),

‘PME earthing facility shall not be used as the means of earthing for the protective conductor contact of a car charging point located outdoors or that might be reasonably expected to be used to charge a vehicle located outdoors, unless one of the following methods is used;’ (722.411.4.1)

A subtle difference, do you not agree?

I‘ve not seen an isolating transformer for a car charger just yet.
I looked into the isolation transformer option some time ago, but the cost was ridiculous, a 230/230v 8kVA is around £853, it weighs around 75kg, and this is without an enclosure (or delivery)

This is from a standard manufacturer, I would expect you will be able to get a Chinese version on-line for around 1/2 of this, but with import duty etc, not sure how big a saving you could make.

the isolation transformer idea, sort of ok as an idea, but I think impractical in the real world for normal charge points.
 
FatAlan

FatAlan

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Trainee
I’m far from being an expert, and have yet to fit an EV charger but from watching the discussions, regs and evolution of the technology... surely they have to be fitted according to manufacturer instructions?
 
Midwest

Midwest

-
Esteemed
Arms
I looked into the isolation transformer option some time ago, but the cost was ridiculous, a 230/230v 8kVA is around £853, it weighs around 75kg, and this is without an enclosure (or delivery)

This is from a standard manufacturer, I would expect you will be able to get a Chinese version on-line for around 1/2 of this, but with import duty etc, not sure how big a saving you could make.

the isolation transformer idea, sort of ok as an idea, but I think impractical in the real world for normal charge points.
Yes thats what I've read here before, may have been yourself.

There does seem to be a lack of clarity on this subject. I wonder if some of these training courses are fit for purpose, no aimed at you @Ed Evans.
 
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