Type AC RCD to Type A RCD for EV charger - require a new consumer unit?

[Milleniumaire]

I've just ordered an EV, which I expect to be delivered in a few months, so I'm now looking into having an EV charger installed.

I've read that a Type A RCD must be used in the consumer unit rather than the older Type AC RCD. Just checked and my consumer unit contains two Hager CD 263U Type AC RCD's, so it looks like these will need to be replaced.

So, is this classed as "work" that will require the current regulations to be applied to my consumer unit? In 2014, exactly 10 years ago no, we had a new plastic Hager consumer unit installed as part of a kitchen refurbishment. I'm aware that a metal consumer unit is now "flavour of the month" and I seem to recall reading that if any work is performed on a consumer unit, it must be upgraded to current regs, which potentially means replacing the plastic CU with a metal CU.

Is this the case or could the EV charger installer (or another electrician I might employ prior to the charger being installed) simply replace the Type AC RCD's with Type A RCD's with no other changes required (assuming everything passes the testing).

I'm also aware that it may be good to have the electrics tested, since it has been 10 years since the last upgrade. Another reason why I may use a local electrician rather than the EV installer.

 

[Adam_151]

I've read that a Type AC RCD must be used in the consumer unit rather than the older Type A RCD. Just checked and my consumer unit contains two Hager CD 263U Type A RCD's, so it looks like these will need to be replaced.

Wrong way around, the requirements generally distill down to
1) there must *Not* be any type AC RCDs in the supply path to the EVSE.

2) The EVSE requires a dedicated RCD which breaks both poles. Nothing actually explicity states it can't be downstream of another RCD of the same rating, however this is a poor arrangement, and a particularly poor one where that RCD is shared with half the house.

3) Depeneding on the EVSE, the RCD at 2 and any upstream devices would normally need to be at least a type A, but there are some out there (probably not many that are still being sold today) that require a type B device.

So, is this classed as "work" that will require the current regulations to be applied to my consumer unit? In 2014, exactly 10 years ago no, we had a new plastic Hager consumer unit installed as part of a kitchen refurbishment. I'm aware that a metal consumer unit is now "flavour of the month" and I seem to recall reading that if any work is performed on a consumer unit, it must be upgraded to current regs, which potentially means replacing the plastic CU with a metal CU.

There is no requirement to upgrade stuff retrospectivly, other than the new work must comply with the current standards, and that includes assessing whether the existing installation is suitable for the addition. You would not be required to replace a plastic consumer unit, just because you are adding one cirucit, but if for example the consumer unit was at the end of a feed to the garage and the supply cable wasnt suitable for the extra load, that would have to be upgraded. If protetcive bonding was not correctly installed that would have to be sorted out etc. Basically as long as the protective requirements for the bit you you are adding are met, and what is there can support the new addition safety, then there is no requirement to upgrade existing equipment as long as you are not making it any worse in terms of compliance than it is already.

Is this the case or could the EV charger installer (or another electrician I might employ prior to the charger being installed) simply replace the Type AC RCD's with Type A RCD's with no other changes required (assuming everything passes the testing).

That would certainly be possibly and likely a sensible upgrade, however its not the ideal way to add an evse cirucit, bearing in mind it'll require its own RCD and sharing an upstream RCD with other cirucits is not good and sharing one with half the house is very much not good.

With Hager you have quite a lot of scope to do things better, most internal components are available to order, so generally you can order an extra neutral bar, mounting clips, tri-rated neutral tail and a section of busbar and create a non-rcd section even if you consumer unit was origninally supplied without one. You can then put an RCBO on that section to supply the EVSE, and hager now do some reduced height RCBOs which break the neutral (ADC9xxR range), although you do have to be very careful which one you are getting as the orignal ones which are still a current product do not break the neutral (ADA3xxG) range

A lot of dedicated EVSE companies have a standard practice of splitting the tails and installing a separate consumer unit for them, sometimes this might be sensible, other times it might not, but they seem to do it as one size fits all...


Have you got a picture of you consumer unit and the surrounding area, then we would be able to suggest what is the most sensible route to expect the installer to go down

 

[Milleniumaire]

Wrong way around, the requirements generally distill down to
1) there must *Not* be any type AC RCDs in the supply path to the EVSE.

Oops, a typo, which I have now corrected. Thanks for pointing this out.

I will take a photo of the CU.

I was just reading about RCBO's and it would be nice to have the additional protection on every circuit, but there will obviously be a cost involved, but maybe it wouldn't be a bad idea to perform an upgrade of the CU now!

 

[Milleniumaire]

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• Milleniumaire
• Thursday at 6:44 PM

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• Milleniumaire
• Thursday at 6:43 PM

 

[Milleniumaire]

Ohme have a "standard" installation, which I "may" get free with the car, or a "non-standard or custom installation", for which they charge.

The standard installation assumes a Type A RCD exists, otherwise it is a custom installation as I assume they would need to change the Type AC RCD(s) to Type A.

There are 3 spare slots. Would it make more sense to use a RCBO for the new EV circuit, rather than another MCB and upgrading the RCD, which as you say would impact on the other MCB's on that RCD.

There are a lot of MCB's on each RCD and replacing the lot with RCBO's (and possibly adding surge protection to the CU), plus a new metal cu is very tempting, if not a very expensive option!

Is there any reason why an RCBO couldn't be used for the new EV circuit?

 

[Milleniumaire]

... just noticed in the details of the Ohme Standard Installation it states:

7. Installation of Mini Circuit Breaker (MCB) or Residual Current Breaker with Over-Current (RCBO), as necessary, to protect the unit and cable run, excluding any Protective Earth and Neutral (PEN) fault protection device (invoiced separately if required).

8. Installation of Type 2 Surge Protection Device (SPD) to protect the charging circuit, unless opted-out by the customer.

So, if they are prepared to install a RCBO, why would there be a requirement for the RCD's to be type A?

 

[Adam_151]

Nice bit of red PVC tape... I seem to remember that the one of these boards that I fitted in my parents house about 12 years ago has had the same thing happen with the door clip, flismy as anything. There is a lot of discussion around here (or was in 2015) about the whole metal consumer units thing, now most of us are of the opinion on it was the wrong solution to a problem. However I cannot deny that I'm glad to see tha back of flimsby plastic board which had been getting cheaper and nastier as time went on. Even Hager's metal board at the time, had more or less the same plastic cover fitted onto a metal box behind.

Anyway I degress, personally if it were me, I'd move everything over to the left a bit and create a non-rcd section between the isolator and the first RCD and use one of the newer RCBOs hager have brought out that break the neutral as well as the Live (a requirement for EVSE circuits. There is a slim change you might already have the extra needed neutral bar in there*, but probably not, but hager make parts like that available to order so not end of the world. I certainly wouldn't advise feeding it from one of your existing RCDs even if you had them upgraded to type A (but it seems thats what one of the companies plan on doing)

*I would not advise you to open and check as that means going near live parts, but can you see the part number on it anyhere? might start VML.....

If they were fitting an RCBO, there would not be a requirement to upgrade the RCDs unless they were planning on putting the RCBO on one of the RCD protected busbars (a poor arrangement and a daft thing to do). But to avoid doing that means you have to plan the job and order the correct hager parts to ensure you can create a non-rcd section on there....

Some of the big EVSE installer companies like to jam small consumer units in the meter cabinet as well, they are not especially re-nowed generally for doing the best installs, they are probably not bad, but they generally like to standardise things, rather than doing the best thing for any particular job, and some of the installers they have may be a little on the untidy side, but there will be some who do take pride in doing things properly, but its generally about standard jobs done quick, like taking your car to kwikfit for tyres

 

[Milleniumaire]

Oh dear, I always take my car to kiwkfit for tyres and for an MOT, just after it has been serviced so I know they can't find anything wrong with it!


Yes, the plastic CU is absolute rubbish and tape has been required to stop it popping open almost since it was installed!

The CU is a Hager VC766H1.

 

[Murdochcat]

All EV circuits must have a dedicated double pole RCD

Plus obviously earthing and bonding must to up to speed too

Don’t take the advice from the EV charger company - it’s the latest version of BS 7671 that the UK works to

 

[ericmark]

excluding any Protective Earth and Neutral (PEN) fault protection device (invoiced separately if required).

That does not sound good, most homes are TN-C-S so unless charging the car in a garage, some form of loss of PEN protection will be required.

However, there seems to be the idea, if one can afford an EV, one can also afford the charge point. The idea that the car may not belong to the homeowner seems to have not been considered. The loss of PEN protection, and the earthing methods with regard to other items within reach of the car, is becoming a major problem. Minium distances from lamp posts etc.

I would say before getting a car, one needs at least a survey to tell you what getting a charge point entails. I can look at my own property and say the car can be parked there, and a TT supply to the car is not a problem, but as to other properties, that's another kettle of fish, I have no idea what underground services you have, and if that will impact where any earth rod can go.

This is not something to work out on a forum, you need someone to do a site visit and decide what you need.

 

[Milleniumaire]

This is not something to work out on a forum, you need someone to do a site visit and decide what you need.

My car won't be delivered for another 5 months so I have plenty of time to sort this out. I have every intention of having a survey done by the EV charger installer, whoever that may be, but I'm also wondering if it's time to upgrade my consumer unit, depending on what may be necessary in order for the EV charger to be installed.

Using this forum is just the first step in trying to become a little more educated and to understand the implications of what needs to be done so when I do have the survey or have an electrician quote me for the work, I understand more about what they are recommending, or what they may be omitting!

I originally assumed (incorrectly) that our setup would be standard as the charger will be installed on the outside of the garage wall and the consumer unit is no more than 5 metres away, inside the garage. However, after a little digging around, I now realise the existing consumer unit is likely to need some work doing to it, so I have to decide if I take this opportunity to upgrade it to current regs and make use of the newer technology like RCBO's and surge protection, or if I have the bare minimum done to allow the install.

 

[ericmark]

The RCD question is minor, to fit a RCBO is reasonably easy, the same goes for 6 mA detection, and loss of PEN detection, but the major question is what is included inside the wall mounted unit? All three can be part of the unit, or integral to the supply, using steel wire armoured (SWA) cable there is no requirement for a RCD to be fitted as the origin of the supply. It can be either end of the cable run.

And where the car is parked also matters, within your house and garage we have Equipotential bonding. Electrical connection, maintaining various exposed-conductive-parts and extraneous-conductive-parts at substantially the same potential. (See also Protective equipotential bonding.) but this is not the case outside in the garden, the drive could, although unlikely, be part of the equipotential bonded area, there is nothing stopping one from used re-bar under the drive to bond the drive, but rather unlikely.

The installed can select the charging unit to reduce what he needs to do around the area of your consumer unit, he can also consider the future, and likely installation of solar panels, and home battery, together with an uninterruptible power supply (UPS) for the house, and the requirement for that to have earth rods etc.

There is also the size of the supply, my home only has a 60 amp supply, but today we are seeing new builds with three-phase supplies, and in the past supplies have served more than one home. There are ways around all the problems associated around EV charging, however you could, by jumping the gun, do work which is not required.

I was incorrectly advised when fitting solar panels, I was told I did not require a smart meter, and this caused problems, as the solar installers put items on the DNO board which did not leave enough space for the smart meter, and they needed to return to move them. We are told we don't need a smart meter, which is true, but if we want split tariffs, with the likely demise of the radio 4 long wave transmissions, if we want to pay less for our energy, we would be cutting of nose to spite one's face not to have one. Forget the stupid adverts, we can't turn lights on/off by clapping hands, but we can have between 5 and 8 hours depending on the supplier of electric at a very much reduced rate. I pay 8.95p off-peak and 31.31p on peak, however the standing charge is now twice what I pay for the electric, at 59.14p per day, so comparing the market is not easy, also the export rate changes if you import from the same supplier, further complicating the sums. And one can also gamble on what the rate will be day to day, in fact hour to hour.

As to how much watching the price really helps not so sure, at £1.34 (£1.93 with standing charge) for 26th June, is it really worth worrying about? However, I know you can use your EV's battery for the home, so if you're not using the full capacity of your car's battery for driving, you can use it to save on the home's electric bill.

However, we started changing our lifestyle to match our solar panels, not sure if that was really a good thing, but we know when to use the three large power users, the washing machine, dishwasher, and tumble drier, basic not after 2 to 6 pm depending on time of year until midnight or 1 am, depending on time being used UTC or BST. With a larger battery, we only have 3.2 kWh this would change, but batteries do have a limited life, so not really worth getting a second one.

This is what you need to work out, can you use your EV's battery to save you money, and how will this affect what type of EV charging point is installed? I had my solar installed in September 2023, and I still have not got the tariffs sorted out fully, we are promised payment from British Gas, but they are dragging their feet.