Tesla Wall Connector - Type B / Type A-EV RCD

[Sirricardo]

Stumbled across 48A/11kW limit on Model 3 LR AC charging - SR has lower maximum, 32A/7.7kW. Not a huge/any difference over the 7.7kW that 32A would give?

Onboard Charger

apologies, but this page refreshes to error page after a few 10's of seconds. But it reiterates other resources that match these rates.

Thanks Vanilla.
Im on the waiting list for a MSM LR 19" tow so I could use the extra charge rate.
However, I have decided to give myself more available charging time by going with EDF (instead of the 5p/hr for 4 hrs OVO??) as their off peak EV rate is from 21:30 till 7:00 @ 8p/Kwhr. The off peak rate applies to the whole house so I might even make a saving. They need to fit a smart meter tho'.
Good luck with your order. I haven't heard a peep sides from the text messages.
I think tow was a bad choice...reserved in 2017.
Cheers. S.

 

[arwooldridge]

Tutorial on RCDs first, conclusions at the end:

One particular case in point is houses or farms with a TT earthing system and a 100mA time-delayed RCD protecting the whole installation against earth faults (that are normally handled by the supplier fuse on other earthing systems). For an installation like that, the Type-EV is more suitable than the Type-B.

Very informative tutorial. One point: with 100mA RCD upstream would this not saturate at a higher level and therefore could a type B RCD (30mA DC?) be used downstream without blocking the upstream one? ie what is the level of DC fault that a standard AC 100mA RCD will operate at. Ditto for 300mA which should even provide discrimination too?

 

[sixela]

Stumbled across 48A/11kW limit on Model 3 LR AC charging - SR has lower maximum, 32A/7.7kW. Not a huge/any difference over the 7.7kW that 32A would give?

Not for European cars. U.S. model 3 SR and SR+ have two on board chargers, with a single phase 32A connection feeding 16A (hopefully 208-240V) to each charger.

In Europe given the ubiquitous 3-phase setups for more power there are three chargers in _all_ model 3, each capable of 16A at 240V.

The manual of the EU wall connector shows it supports up to 32A on all of its inputs, so on a single phase input if you charge a model 3 it will be limited to 3*11.6A@240V yielding 7.7kW, regardless of the model 3.

If you get three phases you can get twice as much into some cars, although only European S and X models will go up to 3*24A@240V (17,3kW; recent US models have 2 24A chargers instead of three, so they charge at the same speed as Model 3 LR), while the EU model 3 is limited to 3*16A@240V (11kW).

The US Wall Connector supports more over a single phase.

 

[sixela]

BTW, I've had someone asking whether you could jury rig a 48A single phase setup going to three 16A on board chargers. Type 2 EVSEs are not just "wiring" and if you don't understand that and you're asking the question you should step away from the circuits immediately!

The US Tesla Wall Connector does support 48A on a single 208-240V phase (it even supports 72A for some Model X and model S), but AFAIK it hasn't been certified for EU usage (in most of continental Europe the wiring gauges and fuses for most household circuits would not support it anyway). The EU Wall Connector has inputs rated at max 32A, so to get more than 7.7kW you need to go to three phase wiring.

The gen2 UMC that you get with the car is also capable of 32A@240V on its single phase input, but the connectors that are delivered with it only support 10A to 13A for household sockets (depending on country) and 16A on a CEE 16A socket. You can get an adapter to a CEE 32A socket, though (which also gives you 7.7kW on a single pĥase, just like the EU Wall Connector wired to a single phase).

That adapter looks like this (currently out of stock -- it is quite popular):

European CEE 32A 6h Type 023 IP44 Blue Commando (Caravan Mains) Adapter for Tesla Model S/X/3 Gen 2 – EVSE Adapters

I really can't find that many EVSEs that would support more than 32A on a single phase in Europe, not even when googling UK sites. All that being said, 7.7kW is fine for overnight charging of even the LR model 3.

 

[Baldrick]

Thanks Vanilla.
Im on the waiting list for a MSM LR 19" tow so I could use the extra charge rate.
However, I have decided to give myself more available charging time by going with EDF (instead of the 5p/hr for 4 hrs OVO??) as their off peak EV rate is from 21:30 till 7:00 @ 8p/Kwhr. The off peak rate applies to the whole house so I might even make a saving. They need to fit a smart meter tho'.
Good luck with your order. I haven't heard a peep sides from the text messages.
I think tow was a bad choice...reserved in 2017.
Cheers. S.

Good choice, I did the numbers and the "crossover" point to move from from Octopus Go to EDF EV tariff is around 5-6 hours of charging a night.
I based mine solely on EV charging and you are right, could have maybe saved a bit more taking other factors into account.
(FYI I went with Octopus Go)

 

[arg]

Very informative tutorial. One point: with 100mA RCD upstream would this not saturate at a higher level and therefore could a type B RCD (30mA DC?) be used downstream without blocking the upstream one? ie what is the level of DC fault that a standard AC 100mA RCD will operate at. Ditto for 300mA which should even provide discrimination too?

Sorry for the late reply - I'm travelling overseas at the moment.

100mA upstream wouldn't necessarily tolerate a higher DC current from a pure physics point of view - the blocking current doesn't itself need to saturate the core to cause trouble, it just requires that the DC bias plus the intended operating current causes saturation. However, from practical considerations 6mA is a smaller percentage of the larger current and so more likely that it is OK just by chance or within tolerance allowances. I don't have the relevant product standards to say what is actually required for conformance - it might still be 6mA even if typical devices are better.

Note also that 100mA/300mA RCDs don't provide full discrimination against 30mA ones unless they are also time-delayed: hard faults (short to earth) will come on at a much higher current than needed to trip either the 100mA or the 30mA, so both are likely to trip. So you need a cascade of delays as well as operating currents to have full discrimination in a large system. That is fine if the higher tier devices are just there for fire protection and/or to ensure disconnection times are met with low fault currents (long wires or TT earthing), but they don't provide protection to save people from direct contact.

For the sort of thing we are talking about here (chargepoints in a domestic context), the two cases likely to occur are:

• RCD at/in the chargepoint, but the cable feeding it also needs to be protected against direct contact (eg. soft-skinned cable buried in wall). Nothing you can do about this, both have to be 30mA instant-acting and won't discriminate.
• Whole-house RCD at 100mA time-delayed because the house has TT earth and faults in/around the consumer unit won't generate enough current to blow the supplier fuse (which is how that problem is protected on PME earthed installs). This will discriminate with a 30mA instant-acting at the chargepoint.

 

[MrBadger]

@arg appreciate your expertise - can I please pick your brain a further time

We have a split consumer unit, with lighting side not RCD protected, but main circuits side on protected RCD side. The consumer unit is in our garage, so circuits for main house disappear up the main cavity for distribution inside the house, but circuits for in the garage are surface.

I have identified a spare MCB, previously used for outside lighting, but now just terminated inside a junction box. This is on the lighting side of things, so no RCD protection, at least not from main fuse box. This all predates us and latest wiring regs but certainly should have been conformant at the time of install as it was all done when new CU was installed by the qualified electrician around 2000.

As we don't have the outside lighting any more, that MCB slot is theoretically up for grabs.

This is me just planning on what to ask a sparky to do. Not a done deal and obviously, what the sparky says goes. But it will form the basis of me getting someone into quote for the job.

Our PV goes into the RCD side of the house. Never felt happy this this as I could imagine that PV could still be producing power for longer than the RCD in that side of the CU takes to trip making the RCD ineffective until PV shits down. I am pretty sure that solar PV is also on its own 16A(?) RCBO but would need to double check. Touch wood, never had a problem with PV tripping.

So my thoughts are to ask the sparky to move the PV to the lighting side, which is non RCD protected (PV would still have its own RCBO) and use the now spare PV slot on the RCD side of the CU for a 32/40A MCB. Then, as per rest of garage, run surface wiring to front of garage where there was a mini CU with a type B/EV RCD. The wall connector can then be run from that.

Short of swapping out the whole CU, does this sound like a plan? I'm just not sure what the ratings are for the internals of these things. We have 100A main fuse.

Thankyou in advance.

 

[pow216]

Can you change the RCD / non RCD split? Often this just means cutting a new bus bar to suit. Personally I’d be slightly happier if the feed to the 2nd was non RCD to avoid having two in series.

 

[MrBadger]

I have no idea, but if that is a recommendation, I could just reuse the space on the non RCD lighting side of things. I was thinking that putting it on the RCD side would protect the cable too.

 

[GM99]

Had a Tesla approved installer come over to provide a quote on putting in a Tesla Wall Connector.
The quote received stated:

‘Tesla charging point installation, including type A rated RCD unit’

I queried this as had heard through this forum that the legislation had changed this year and that RCD Type B was now required.
Response from the installer below:

‘I confirm, by the Uk Regulation 722.531.2.101 BS7671 for the EV chargers RCD Type A is required.’

Bit confusing as this is one of the recommended installers on the Tesla website.

 

[Tony Hoyle]

I'd just go elsewhere.. when you know more than the guy you're paying to do the job that's a bad sign!

 

[MrBadger]

I just found this which may possibly clarify things - personally I think that I would much prefer an all in one solution.

The new wiring regulations BS7671:2018, 18th Edition Section 722.531.2.101 approves two provisions of DC fault protection:

• Use type B RCD, which is suitable for AC and DC fault protection but usually the costs are 10 times the cost of type A RCD.
• Use type A RCD and a DC 6mA sensor to provide a means of disconnection of supply in case of DC fault, which is commercially a much more attractive solution.

The website is trying to sell their alternative solution.

 

[sixela]

That 6mA DC sensor is either in the EVSE itself (not with a HPWC) or (since it measures a DC residual current) something like a type EV RCD.

They are right: you don't require a type B, but if you have an existing type A RCD you need some kind of type EV RCD downstream so that DC residual currents over 6mA cannot reach the type A RCD.

They're also right that the downstream RCD need only detect DC residual losses. But a sensor is not enough, you also need to break the connection when a DC leak is detected. Which is why people call RCDs “devices”: they sense and then they also act. Of course that can be implemented using a sensor that controls another device (e.g. a controlled circuit breaker).

 

[pow216]

I finished my Tesla Wall Charger install this weekend. Total cost £956.82. That include the Doepke Type A EV RCD, putting a 2nd consumer unit in and an Earth Rod. Took me about 2 days all in.

I've had an electrician to quote me on certifying the work, that will be an extra £60.

 

[pow216]

This is worth a watch (Rolecs cheaper DC protection):-

 

[Sirricardo]

I finished my Tesla Wall Charger install this weekend. Total cost £956.82. That include the Doepke Type A EV RCD, putting a 2nd consumer unit in and an Earth Rod. Took me about 2 days all in.

I've had an electrician to quote me on certifying the work, that will be an extra £60.

Would you mind sharing a parts list and some pictures? I have the same setup to install shortly.
Thanks S.

 

[Kaleb]

I have just purchased a Model 3. As I understand it it comes with a "TESLA MOBILE CONNECTOR" with a standard 13A plug but it can also be provided with a 32 amp blue "Commando" plug. I live on a farm and we have a couple of 32a sockets for farm equipment. Both these sockets are protected with RCD's etc. Is the "TESLA MOBILE CONNECTOR" protected against DC fault leakage?

 

[Fullerene]

I have just purchased a Model 3. As I understand it it comes with a "TESLA MOBILE CONNECTOR" with a standard 13A plug but it can also be provided with a 32 amp blue "Commando" plug. I live on a farm and we have a couple of 32a sockets for farm equipment. Both these sockets are protected with RCD's etc. Is the "TESLA MOBILE CONNECTOR" protected against DC fault leakage?

I don’t believe the UMC has DC protection, the TWC doesn’t. You’ll need to get a 32A adapter, I just picked one up from Tesla recently. I don’t have a 32A commando socket yet, I’ve no Intention of installing a dc type ev breaker. It seems pointless, nobody is asking you to install the ludicrously expensive breaker for any regular 13A mains socket.

Take a look at

Here's how to charge with 32A commando in UK

 

[Kaleb]

This is as I suspected. I have read the extremely interesting and erudite comments on the subject of DC fault protection and have come to the conclusion that if DC fault protection is required because of the potential hazard it should be incorporated either in the vehicle (why not?) or within the UMC. To my mind the latest regulations make no sense if they can be circumvented by simply using an external socket and a UMC (13A, 16A or 32A, it's irrelevant; the DC fault current is the only thing of note and this can happen at any AC current level under certain fault conditions and thus saturate any normal protection transformer within the RCDs). I note that builders are installing "EV Wall Pods" in new builds that incorporate a 13A socket but do not have DC fault leakage protection. This, apparently, is perfectly ok as far as the 18th edition is concerned. Have I missed the point? I'm completely new to this business and only started to take an interest when I saw the cost of compliant devices!

 

[Fullerene]

it should be incorporated either in the vehicle (why not?) or within the UMC

The IET having limited scope, I dread to think what would happen if their remit included EVs in the UK. If there was a need for DC protection it only makes sense to put it in the car. Otherwise, as we all take the time to learn, there are numerous ways to legitimately circumvent the DC breaker requirement by the user. I am not aware of any DC incident the type of which the this is meant to protect from. It smells of excess belt and braces without the support of evidence or a need; health and safety gone mad etc.. It also smells of the IET wanting to feel like they're part of something bigger. They could be more useful by perhaps creating an advice for householders leaflet on the subject.

I note that builders are installing "EV Wall Pods" in new builds that incorporate a 13A socket but do not have DC fault leakage protection. This, apparently, is perfectly ok as far as the 18th edition is concerned. Have I missed the point?

Wasn't aware of this, probably an external weatherproof regular socket marketed as somewhere to plug a car into, anyone able to provide further information on this?

It amuses me to see new builds with big roof areas that only have the 1 or 2 token PV panels. I imagine the inverter will be 600W or similar. It's a nod in the right direction, would be much better if it was done properly.