EV Zappi Charger Install

[griffta]

Hi all,

I wonder if someone in the know could provide me some electrical advice. Today I've had a company install a Zappi 2 charger for my electric car at my home address. I wanted the supply to come off the main CU board as there was a spare way. The CU is a cheapy split load BG board (apologies to the Hager gang).

The install went well to begin with, around 13m of EV Ultra 4mm2 SWA was ran through my basement and out to the Zappi. The SWA was connected through to a 40A MCB (and in turn through one of the RCDs).

When the installer powered up the system, he said that both RCDs in the CU instantly tripped. This happened every time power was applied to the zappi circuit.... I left him to it to figure it out.

Some time later, I caught up with him as he was putting the cover back on the CU. He said that he had spoken to Zappi who has advised him to connect the Zappi supply in to the feed side of one of the CU's RCDs rather than via the MCB and load side of the RCD.

I was becoming concerned about what overcurrent protection would be in place to protect the SWA cable, but as I was unsure of my concern, I didn't raise this with him.

After he left, I phoned Zappi to ask if this method of connection would be permissible. As I feared, they confirmed that the Zappi and supply cable must be protected by an MCB of correct type and rating (as a minimum, with an RCD also being required if the cable is being buried or otherwise not visible).

I didn't feel confident in calling the installer out at the time, call me a coward.... he was meant to be the qualified electrician not me.

I've arranged for an independent electrician to come and have a look and advise. I've also emailed the company for their response, so I wont name them until they've had a chance to rectify.

What are your thoughts? Am I making a mountain out of a mole hill here?


Many thanks,

Matt.
(p.s. I've got a keen interest in electronics, but have an overriding respect for those who are qualified!)

 

[conny]

If the installer appears to have done something incorrectly, (as it appears to have been confirmed by the manufacturer/supplier), then you have done the right thing in getting someone independent to look at it. Once you have his report you should contact the installer and get him to correctly rectify his mistake and possibly pay the charge of the independent guy. (Though don't hold your breath).

 

[bernardgreen]

he said that both RCDs in the CU instantly tripped.

That suggests the "installer" had connected the Neutral for the Zappi to the wrong Neutral bar in the CU.

RCDs operate and trip when the current on their Live is not the same as the current on their Neutral.

In your case the current from Live to the Zappi was flowing through RCD 1 on its Live and the current returning to the Neutral was flowing through RCD 2 on its Neutral.

 

[griffta]

Thanks, the logic certainly makes sense that the Neutral was connected to the wrong bus bar, it's worrying though how this wouldn't have been identified in basic troubleshooting as a qualifies electrician.... hmmm...

 

[RF Lighting]

I wonder if EV charger installers go to the same training school as solar PV installers?

 

[AndyPRK]

I’d swa cable was used (eg black round) rcd isn’t required at cu.

But yes an Mcb should be used

 

[flameport]

The SWA was connected through to a 40A MCB (and in turn through one of the RCDs).

Not permitted, as the RCD in that BG board won't be the correct type for supplying EV.

Should be an MCB of suitable rating only, no RCD. That's the reason for using SWA - no RCD required (unless on a TT supply).

When the installer powered up the system, he said that both RCDs in the CU instantly tripped.

Incorrect connection within the CU - a very basic error that should not be made.

 

[Adam_151]

I wonder if EV charger installers go to the same training school as solar PV installers?

They did, but that school has now rebranded again, its now the private rented EICR training school, but only for a limited time only (Until the next band wagon comes by)

 

[ericmark]

Do BG make a type F or type B RCD? Maybe they do, but it would not likely be fitted in a standard consumer unit, seems more likely either a 6 mA DC cut out needs to be used or a type B RCD inside the Zappi unit. It seems wrong that any electric car charging unit should be supplied by the same RCD as rest of the house. But I have not done the course.

 

[Risteard]

Not permitted, as the RCD in that BG board won't be the correct type for supplying EV.

And also because it is a requirement that each and every EVSE is supplied through a dedicated RCD.

 

[ericmark]

And also because it is a requirement that each and every EVSE is supplied through a dedicated RCD.

Are you sure? I read this on the fitting of a 16 amp pod point solo and it seems to suggest since is has

RCD protection: From January 2019 new Pod-Point’s will include 6mA DC vehicle fault protection and only Type A RCD/RCBO’s are required at source, if the Pod-Point was built earlier than this Type B RCD protection should be fitted at source, the symbols printed on the RCD in figure 1 can be used to identify the type of RCD protection.

it seems some are now designed to connect to a type A RCD/RCBO

rather than the type B

however looking at most the the BG consumer units, they seem to be fitted as standard with type AC

which is not suitable for an electric car charging point.

Integral Earth Leakage Protection Integral 30mA Type A RCD (EN 61008) + 6mA DC protection (EN 62955)

Rated Current 32A max

Circuit Breaker 32A Curve B
Earthing Arrangement TN: can be connected to the PME supply. Complies with BS 7671:2018-amd1:2020

So it would seem a 32A type B MCB with a high integrity consumer unit using SWA cable would be the way to go. But the specs do seem to call for a 32A type B.

 

[AndyPRK]

Zappi have the RCD built into their unit,
and if using SWA, no RCD required up front.

 

[ericmark]

Zappi have the RCD built into their unit,
and if using SWA, no RCD required up front.

Yes but does need a MCB type B up front.

 

[securespark]

Isn't a 40A MCB too big for 4milli SWA clipped direct?

 

[ericmark]

Isn't a 40A MCB too big for 4milli SWA clipped direct?

No seems Multicore armoured 90 °C thermosetting insulated cable 4 mm² rated 49 amp. However it does seem Zappi call for a 32A type B so still too big.