Not RCD protected (SWA) versus single pole to EV

[equitum]

If an EV charge point has sufficient RDC-DD integral RCD protection, my understanding is that this can be supplied from a non RCD circuit provided the installation method is deemed appropriate, e.g SWA.

The regulation (722.531.2.101) requiring every charging point to be double pole RCD protected is to me subjective in that it is not clearly stated whether the circuit/wiring supplying the EVCP or the EVCP itself, with integral protection must comply.

Given that an SP RCBO (typeA) provides the same protection as an MCB supplying the EVCP in say SWA with additional protection on the line supply, my view would be that is preferable to just from an MCB (where/if permitted)

Has this been clarified on here or elsewhere before ?

 

[flameport]

They can be supplied from an MCB only if the EVSE contains an RCD which complies with one of the appropriate standards.

Most EVSEs have claims such as 'equivalent protection to... ' which is not the same as complying with the standard, and therefore an RCD to one of those standards is required in most situations, and that must be a multi pole device which disconnects all live conductors.

 

[ebee]

I will ditto what Flameport has just said.

Just to clarify to some reading this topic.
The term "Live" means an Line conductor and any Neutral conductor - in other words any conductor that carries current as part of its intended function.
It is not uncommon for people to refer to Live, Neutral and earth inside, for example, a plug (plugtop) but the correct term is Line.
So with single phase we have Line and Neutral and both are Live and with three phase we have Line 1, Line 2, Line 3 and Neutral and all 4 are Live.
So in a single phase system you would disconnect both Line and N, and in 3 phase then all of the phases (lines) and the N if present.
In short, the N conductor must be disconnected too.

I know that most of us are aware of it but someone visiting the forum may not be aware of it.

 

[equitum]

They can be supplied from an MCB only if the EVSE contains an RCD which complies with one of the appropriate standards.

Most EVSEs have claims such as 'equivalent protection to... ' which is not the same as complying with the standard, and therefore an RCD to one of those standards is required in most situations, and that must be a multi pole device which disconnects all live conductors.

Good point thanks. I often tie myself in knots trying to design an installation that is safe and compliant, is cost effective/pragmatic for the customer and most aesthetic/least disruptive etc. the reality it’s not my problem. In this case I was trying to use a split load garage sub board fed off a split load main board both type AC- which means changing devices to solve upstream/downstream RCD issues and selectivity and providing double pole RCD and SPD bit of a headache The meter tails some way from the main board which make the CT wiring a pain (which is why I specced a Zappi ) but customer went and bought BG crap). Understandably all hard for the customer to grasp these subtleties. But the reality is the solution is a separate EV board either off the tails or from an MCB in main board and a cable across the front of the house or in a trench and if he doesn’t want to go for it he can go elsewhere !

 

[Adam_151]

Its interesting to note that even the zappi falls into the trap of 'equivelent protection to'. This came up in a discussion with the NICEIC assessor, he was telling me he'd been to see another contractor and the point got argued (I think the wording in the zappi MI may have been more vague at the time) but it ended up with a phone call to the myenergi technical dept about what standards approvals the protection has, and it terns out it doesn't, it only has equivelent protection to.

My personal thoughts are, and it wouldn't be a compliant installation, but units like the zappi, if they state they give equivelent protection to an RCD, and they break the neutral on an unexpected* power off (i.e. mcb being flicked off when charging), then I'd view supplying it via an RCBO which doesn't break the neutral as extremly low risk, the standards approved device provides the additional protection, and the neutral to the EV does get disconnected when EVSE looses power as a result.

*This is important, some units use latching relays, and its possible some of them may not return to the same state they are in when idle when they unexpectedly loose power

I did start to go down the rabbit hole of I wonder whether an RCBO which was software driven would be able to be compliant as there might be a bit of reluctance to trust safety to software, then I realised that we are actually already there, because AFDDs definatly are, and I wouldn't be supprised if supprised if some RCDs have MCUs rather than dedicated silicon, and then there are addressable fire alarm systems which definatly do rely on software to provide safety.

 

[equitum]

Good point thanks. I often tie myself in knots trying to design an installation that is safe and compliant, is cost effective/pragmatic for the customer and most aesthetic/least disruptive etc. the reality it’s not my problem. In this case I was trying to use a split load garage sub board fed off a split load main board both type AC- which means changing devices to solve upstream/downstream RCD issues and selectivity and providing double pole RCD and SPD bit of a headache The meter tails some way from the main board which make the CT wiring a pain (which is why I specced a Zappi ) but lcustomer went and bought BG crap). Understandably all hard for the customer to grasp these subtleties. But the reality is the solution is a separate EV board either off the tails or from an MCB in main board and a cable across the front of the house or in a trench and if

They can be supplied from an MCB only if the EVSE contains an RCD which complies with one of the appropriate standards.

Most EVSEs have claims such as 'equivalent protection to... ' which is not the same as complying with the standard, and therefore an RCD to one of those standards is required in most situations, and that must be a multi pole device which disconnects all live conductors.

Actually John I think your first paragraph is incorrect. The wording (regs) is “Except where provided by the EV charging equipment protection against DC fault currents shall be provided by ……compliance references to BS62955 for the RDC-DD, , BSEN 61008-1 etc for RCD

Therefore provided the equipment is compliant with BS EN 62916 it should be deemed that said devices comply with either the EV equipment standard and /or the wiring regs and no additional upstream RCD is required (other than for any other circuit requirement such as concealed cables etc)

 

[Risteard]

Actually John I think your first paragraph is incorrect. The wording (regs) is “Except where provided by the EV charging equipment protection against DC fault currents shall be provided by ……compliance references to BS62955 for the RDC-DD, , BSEN 61008-1 etc for RCD

Therefore provided the equipment is compliant with BS EN 62916 it should be deemed that said devices comply with either the EV equipment standard and /or the wiring regs and no additional upstream RCD is required (other than for any other circuit requirement such as concealed cables etc)

I disagree. Clearly this integrated "RCDs" do not comply with BS EN 61008 or BS EN 61009 for example, and I have long held that this therefore does not meet the requirements of BS 7671. It seems that more in the NICEIC are coming to accept my interpretation of that. I have never installed an EVSE without a dedicated (i.e. not protecting any other circuits or equipment) RCD which breaks all live conductors protecting the circuit supplying the EVSE. The only common RCD I have installed on some of these installations is an S-type RCD upstream of these, perhaps at 100mA or 300mA.

 

[equitum]

I take your point however bs7671 does not define product standards for equipment and equipment does not have to comply with bs7671. In terms of EV equipment there is a BS 62916 which if compliant with then the onus is on the manufacturer not the installer to deem compliance of the components or equivalent BS standards within it . The regs, in this case are giving definitions of standards required where the installer is providing external RCD and RDC devices.

 

[ericmark]

I do see a problem with EV charging, it can be a dedicated unit with all bells and whistles, but it can also be a plug in device, so the same 32 amp commando socket can supply the welding set, or the EV charger. And as installer we have no idea if the 32 amp socket is going to be used for one of these and it does not need to be 32 amp there are also 10 amp versions, and we actually see 13 amp sockets like these sold as EV charging points, the lead may have RCD and RDC built in, but they seem to lack any loss of PEN protection. Also of course no load shedding if the house use goes up, for a car parked in a garage I suppose there is no real problem, if OK to use a welding set in the garage then also OK to charge the car.

It is only when used outdoors when the problems arise. And the same problem arises using a patio heater which is class I. @flameport has given a good answer, as usual, but at the end of the day, one needs to use some common sense. I have looked for type F and B RCBO's single modular width and they don't seem to be made, we can get double pole as far as the switching goes, but only the line goes through the overload. And we can now get type A rather than the old type AC.

As you say there is BS 62916 however I have a copy of BS 7671 although out of date, but I am unlikely to ever see a copy of BS 62916. I note the pictured lead says

as to if it really detects loss of PEN not so sure? Just glad I have retired and don't need to worry about things like this.