Swapping circuit from RCD protected to unprotected

[mojo8472]

Hey chaps,

I've recently ordered an electric car, and the guys installing the charger want me to get the MCB running to the garage CU swapped from the RCD-protected side of the house CU to the unprotected side.

Is this as simple as flipping the meter isolator and swapping the neutral wire coming from the relevant MCB from the RCD neutral bar to the unprotected neutral bar? If it's anything more complicated than that I'll get the electrician in!

Cheers!

 

[securespark]

Why do they want you to do it??

If your existing supply is unsuitable, they should be arranging to rectify it.

And I don't think what they are proposing is the way to go about it.

They don't sound very professional to me.

 

[Iggifer]

It is WAY more complicated than that. Why can it not be RCD protected?

 

[mojo8472]

Here's the communication I've recieved from the charger installers:

"We just need to to arrange for you electrician to move the wire for the garage from the RCD side of the fuse board to a none RCD breaker.
This will allow us to then install what’s known as a Zedy Ready 2 way consumer unit directly of the garage fuse board, which we can then connect the charger."

 

[EFLImpudence]

Is it because they want to fit an RCD in the garage?

Anyway, they should be doing it.

 

[Iggifer]

This will allow us to then install what’s known as a Zedy Ready 2 way consumer unit directly of the garage fuse board, which we can then connect the charger."

Google brings up 0 results for a Zedy Ready consumer unit. I wouldn't want ANOTHER consumer unit added if I could avoid it. Can they not just feed it from your existing garage consumer unit? It's no more work than adding another one

 

[flameport]

Presumably this 'Zedy Ready' thing contains it's own RCD, and they don't want 2 of them in series, as a fault with the charger would cause the garage to be disconnected.

However just removing the RCD for the garage is not the solution, the charger should have it's own separate circuit.

 

[EFLImpudence]

Haven't found anything relevant -

http://www.lcie.fr/en/1018-your-industry/charging-infrastructure/ze-ready/process.html

 

[ban-all-sheds]

"We just need to to arrange for you electrician to move the wire for the garage from the RCD side of the fuse board to a none RCD breaker.
This will allow us to then install what’s known as a Zedy Ready 2 way consumer unit directly of the garage fuse board, which we can then connect the charger."

Tell them that your electrician has said that the supply to the garage cannot be put on the non-RCD side of your board as the cable is buried in a wall.

Tell them that if they are not able to install the necessary equipment without contravening the Wiring Regulations, and therefore without (in practice) breaking the law, then the deal is off, and you'll find an alternative supplier who can be trusted.

See what they say.

And...

I've had a quick look at one document which talks about ZE Ready - IHNI how accurate or authoritative it is, but on the basis of that you really do need to get an independent electrician on board ASAP, someone who you can trust more than the clowns who are going to install the charging point, because that might be simply incompatible with being on any circuit from your house CU (there might be Type C or D breakers in their new CU). Also, have they asked you what type of earthing your supply has? Will you be having an outdoor charging point?

 

[ericmark]

There has been a lot of talk about supplies to cars, caravans and boats from a domestic supply. With a commercial supply it would need making into TT which means using an earth rod. But with commercial the fire regulations require a distance from the house which means there is no problem with using a TT installation. However with domestic there is often not the distance required to be able to have the house on a different earthing system to the car, caravan or boat and so there has been a lot of talk about the correct method.

One method is to use a charger which includes an isolation transformer, which seems to be the favoured way. In which case it does not matter what RCD protection the supply to the charger has as the output is isolated anyway.

The IET has written a code of practice which has informations as to:-

• When to use TT earthing
• Special precautions for connecting to TN-C-S (PME supplies)
• The use of electrical separation, isolating transformers and RCDs
• The need for a separate, dedicated electrical circuit for EV charging.

Since I am not fitting chargers I have not bought the code of practice, if I was going to do the work then I would buy the book. The update to the original manual talks about 10 meters between TN-C-S and TT installation. The milkman up the road has the van just 2 meters from the house and likely not 10 meters from road, and there is public access to the charging area, i.e. no gates. But what we don't know is what the risk assessment stated or if it actually complies.

It is rather a specialised subject.

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