EV Charger Questions

There is no issue having an MCB in the consumer unit feeding an RCD in a box (or even an RCBO in a box), as an alternative when you do not have a suitable RCBO.

But the section of cable between them that is not RCD protected and so needs to be either surface wired, so visible ,or armoured if hidden or protected to an equivalent degree (metal trunking / steel conduit or whatever.) Obviously the cable needs to have current rating to  match or exceed the MCB ....


If it has to go far then a length of SWA is often the easy 'route anywhere'  way.


Also be aware that some EV charger designs require a type B RCD that detects DC faults- not to be confused with a type B MCB.

You may like to sit down before checking the price of those, and then make sure to buy a charger that does not require this.


Then there is the as yet unraised issue of earthing the charger and how your house is earthed. If the care is outside to charge, you may need to make the charger a TT island, and if the house is PME that means keeping it away from anything that may be earthed to the house earth.

M.

Hi M,


Thanks for your reply. 


The Pod Point has PEN fault detection, so I am OK on that point. They also have a 6mA RCD build into their circuitry, and advise the installer uses a type A RCD upstream. 


Thanks for the clarification on MCB before RCD.

And the earthing ?


Mike.

Earthing is PME - according to PP their product and its PEN fault detection negates the need for an earth rod

You need either a Type B double pole 30mA RCD or Type A with DC protection.


The RCD has to comply with BS EN 61008 or BS EN 61009. You cannot have compliance with those standards on a PCB.


BS 7671 722 lists a number of BSs and BS ENs that the charging installations have to comply with. Ask you charge point manufacturer for a Declaration of Conformity indicating their equipment complies with those requirements. Also the equipment or the packaging has to be CE or UKCA or UKNI marked.

You need either a Type B double pole 30mA RCD or Type A with DC protection. The RCD has to comply with BS EN 61008 or BS EN 61009. You cannot have compliance with those standards on a PCB.

Presumably we'd be OK with DC protection built into the charge point and then an ordinary 30mA A-type RCD feeding that (which I suspect is the pod point approach).

   - Andy.

And the SPD?

If I'm not mistaken, SPD is advised but not a requirement, therefore doesn’t need to be implemented?

John Peckham:

You need either a Type B double pole 30mA RCD or Type A with DC protection.


The RCD has to comply with BS EN 61008 or BS EN 61009. You cannot have compliance with those standards on a PCB.


BS 7671 722 lists a number of BSs and BS ENs that the charging installations have to comply with. Ask you charge point manufacturer for a Declaration of Conformity indicating their equipment complies with those requirements. Also the equipment or the packaging has to be CE or UKCA or UKNI marked.

I went to the NICEIC for their view. I havent included my question but it is rather obviously based on JP's post. 
Hello Lyle,

Thank you for your enquiry,

 

Regulation 722.531.3.101 of BS 7671: 2018 amended 2020, requires that unless the protective measure of electrical separation is used, each charging point shall be protected by a 30mA Residual Current Device. Within the same Regulation it states that the RCD shall comply with one of the following British Standards; BS EN 61008-1, BS EN 61009-1, BS EN 60947-2 or BS EN 62423.

 

There is some debate as to whether the RCD components installed within some manufacturers’ charging equipment comply with the above requirements.

 

At this moment in time Note 5 of Regulation 722.411.4.1 places the emphasis of ensuring compliance squarely on the shoulders of the electrical designer/installer, as can be seen in the Note below;

 

 

We would therefore agree with your suggestion of the installation of a recognised Residual Current Device upstream of the charging point, where any doubt exists. With regards to the issue of a lack of selectivity, so long as this does not cause a dangerous situation to occur, it would be acceptable. As the two RCDs are in series on a dedicated circuit, it would be difficult to envisage a dangerous situation, however as the installer this would be a decision that you would have to be satisfied with.

 

Hi,


What about surge protection? 


I don't have any room for this, but could add a separate enclosure in the DNO enclosure next to the meter outside if required.


I know it would add protection for the whole property, but there isn’t a requirement to do so.