Don't Make This Mistake When Installing an EV Charger - RCD & RCBO selection.
The UK wiring regulations are very specific when it comes to choosing RCD protection for electric vehicle charge points. Most electricians know about the need to avoid type AC RCDs. However, hidden within the regulations is the need for RCDs which isolate all live conductors. This is easy when selecting a regular RCD but causes some challenges when choosing to protect a circuit with an RCBO. An RCBO is a combination of RCD and MCB circuit protection. Most RCBOs only disconnect the line conductor. In this video, we explain the RCD requirements of BS7671 and the difference between single, double and single pole and switched neutral RCBOs.
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00:00 Do you need to fit double pole RCD's for EV chargers?
00:36 What do the UK wiring regulations say?
01:00 What is a live conductor?
01:50 easier with split local RCD boards
2:15 RCBO identification using diagrams
3:44 Double Pole RCB with switched neutral
4:30 Double pole or switch neutral what is the difference?
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I’ve made this comment before on other videos… an RCD or RCCB protecting a group of circuits is NOT suitable for an EV charge point installation as part as regulation 722.531.3.101 says that it must be INDIVIDUALLY protected unless using the protective measure of electrical separation. The operative word being “individually”.
As always Joe really clear and concise. Brilliant video
Thanks 🙏
Very, very important topic. Thank you. 👍👍👍
Years back we installed 2pole brakers when we upgraded all our ped op charges and double decker charge leads at current work place as the way there used
In Pakistan I'm pretty far from installing those EVC, however it's good to know such details.
I was told by Rolec technical that because their unit had a DP RCBO in it the circuit supplying it could be fed from an MCB in the board, obviously so long as the cable didnt require additional protection ie SWA clipped direct.
Yes 👍
Same applies if a MATTE’ box is fitted.
The RCBO type disconnecting all "active conductors" is the standard to use for us here. We don't call them live conductors, we call them "active conductors", definition is the same as the one you use in the UK. So the lines and the neutral are active, a PEN is not active! That's the reason you can't retrofit RCBOs or RCDs on some old installations here, because they're TN-C in the final circuit and don't have a separate CPC, and it's not permitted (and neither a good idea) to isolate the PEN. And one thing when doing this on three-phase circuits: There's always a special N terminal, there you'll have to connect the N to, and not something else! When you isolate the neutral in a three-phase circuit the N must be isolated last after the lines, and reconnected first before the lines in such isolators/RCBOs/RCDs!!
Good expression that, "active conductors" I like it. 😊
Yet again, irrelevant and unnecessary use of terminology that causes ambiguity! Why "active" why "all conductors"? BOTH cause ambiguity. Just keep it to simple, plain English. Just say "... AL Live and Neutral conductors" (preferably capitalised to indicate the named contacts)! No confusion, no ambiguity about whether or not the PEN is involved or not. The rule just needs to say "all Live and Neutral connductors" and because of the earlier reference to RCDs it is OBVIOUS & CLEAR that this rule applies to RCDs!!?? 🤔😲🙄
@@boblewis5558 The lines and the neutral, both are considered as "live conductors" in the UK, and here in Germany we call them "active conductors" instead. And it's not permitted to isolate a PEN, because then the protection of the circuit would be gone too. The PEN is a combination of neutral and protective conductor, so it carries operational currents and also in addition fault currents. RCBO contains RCD- and MCB-functionality in a single housing. Doesn't change that the British regs state that on some occasions all live conductors (line and neutral) must be isolated. And here in Germany we do it always.
Howdy. Very informative. One advantage in breaking the Neutral too is that the breaknig is faster. The arcing will be quenched faster thus minimizing the risk for contact welding shut or arcing explosion. Also. There is always a residual potential between Neutral and Earth which can be unpleasant to experience when getting into the car only to fetch something. Regards.
Point
I always wondered why some MCB's have the (bump and square) symbole, but others like the double-pole one @ 4:34 don't? After all they all have thermal and magnetic protection built-in.
Since Neutral is connected to Earth at the supply transformer the function of a RCD is to prevent Live potentials flowing into Earth. The only reason I can think of for disconnecting the Neutral would be that an electric car also has a supply source and an electrical charge fault could possibly result in currents flowing between Neutral and Earth. It would be good to know what fault protection switching the Neutral provdes even if it is a mind bender.
Really interesting content. Thanks. 👍
Our pleasure, thanks for watching and commenting. 😊
Joe seemed to suggest that the RCCB in a split load board can be used for the EVC cct, providing it's not a type AC. However, in domestic settings, for example, section 6.12.3 of the EVC CoP (4th ed) says that every charging point shall be individually protected by an RCD... so seems clear that the RCCB protecting a number of ccts cannot be used. The section also makes it clear that the neutral should be disconnected.
That depends on how you read it, "every charging point shall be individually protected by an RCD". Could mean you can have other loads on the same RCD but not two chargers
EV Charger Manufacturer advised that no double pole rcbo is required as the EV Charger Equipment has got one built in and disconnect both live conductors. Only for the supply cable need protection and you can protect it with mcb if swa or a type rcbo (switched or non switched neutral). Could you shed some light on that?
The only correct term is Simgle pole + neutral. In the Netherlands that translates to: 1P+N. When you call something 'double pole' I (and a lot of other people) expect a true 2P that monitors and protects both poles.
? how about be N, + swPh . The comma after the N would define the switching ability to only the Ph, Line, or Live (your choice of terminology - think it's often called the hot in USA).
Scary, surely if an installer doesn’t know the difference between single and double pole they shouldn’t be installing it in the first place?
You'd be surprised...
It's very annoying when you can't get double pole rcbos for certain boards .
The bizarre thing is that many "value" brands have double pole RCBOs, while many more premium brands do not!! Hager doesn't, yet Lewden, Fusebox and Verso all do....
Good stuff
Thank you! 😊
Very good video guys. That board behind you has the SPD at the end of the board shouldn't be after the main switch??
Think it depends on the manufacturer really, the SPD doesn't even need to be in the board.😊
@@efixx yeah I understood it to be closest to the origin as possible so either separate to the board or closest circuit to the main switch. But maybe down to manufacture I'm not saying its wrong on your board just seeing what you think as I've not seen at the end before.🤷♂️ This channel best channel on KZhead by far keep up the great work guys👍
Excellent Thankyou
Our pleasure!
(I'm not an electrician) - it's important to note the difference between 'live conductor' and 'line conductor' Many people call the brown the 'live' and are unaware it's now the 'line' conductor. The neutral and line conductor are both together now 'live'
Absolutely it is. 😊👍
Competence is the important thing to note…
How about TT systems in general? they too require double pole rcbo’s to break all line conductors. I know manufacturers have to pack a lot of shit into these devices!! But double pole rcbos are difficult to get hold of with certain manufacturers! Which can be frustrating. Great video chaps, keep them coming👍
For a TT system you'd typically use a time delay upstream of the RCBOs - and this would normally double as the main switch and therefore be chosen as a double pole device. There's a debate as to if 30mA RCD's [which RCBOs contain] should be used for fault protection that is open to how you interpret the standard. Personally I'd only use 30mA RCD's for additional protection. A TT should never have a fault impedance of over 500 ohms and so can always accomodate a 100mA time delay RCD.
@@keirstitt8277 ? What is the argument for Not using RCBOs as 30 mA as additional protection ?
Great video, but how can the RCD selectivity problem now be solved without driving up the cost considerably. My NAPIT inspector made me remove upstream RCD protection for this reason
If there's no RCD protection built into the charge point which is the way most manufacturers seem to be going now then there is no selectivity issue. If it is built in to the charge point feed it with a cable like SWA or install the cable so no RCD protection is required to protect it. 👍
Sticking a single brand of charger also helps so you have half a chance of following what they have going on inside.
can i fit type A rcbo if the charging point doesn’t have one? and if the charger has got rcd dd and i run 6mm cable embedded in plaster would i need to protect the cable with rcd a?
Just spoken to a guy on NICEIC tech line and he said to be wary of single module 1P and switched N RCBO devices for this application - in that although the N may be switched only the Line will be disconnected (isolated) by the standard 3mm contact gap. Whereas double module RCBOs and RCCBs will disconnect both live conductors by 3mm. I guess you'd have to inquire of individual manufacturers - even the product data sheets and the schematics don't necessarily answer this.
Reg 722.531.3.101 says a charger needs to be protected 'individually' by an RCD. Does that mean a split load RCD shouldn't be used if its also supplying other circuits?
That’s caught a few people out I bet still good info
Learning is king! 👑
What about the new type charger points that have double pole contactor, pen fault detection and RCD built in ? The manufacturers say no RCD requirement if wired in SWA up to the unit.
Then the RCD in the charge point should disconnect all live conductors. 😊 Interesting that that seems to be the way things are going to you, we've noticed a trend for manufacturers to remove the RCD protection and rely on the installer to provide it. 🤔
Like the zappi he’s showing !!
@@efixx many thanks for a reply. Always love watching and often learning new things. ICS intelligent charger has the onboard protection that I have installed ( my inspector thought I should install a double pole 61009 also as he wasn’t convinced about the inner workings of the charger being double pole) but as for trend on what manufacturers are trending towards I don’t install enough to say .
I’ve been looking for a video like this for a while! I’ve a Lewden consumer unit and wonder if the EV charger comes with an RCD built in like the Zappi, can I still use this double pole RCBO? Or would an MCB be better? As in is it OK to have Two RCBO?
If the charge point has the RCD protection built in there's no need for an RCD at the supply end for the charge point. However depending on how the cable from the consumer unit to the chargepoint is installed it may need RCD protection. Might be best to install the cable so it doesn't need RCD protection in that case. Or pick a chargepoint with no RCD protection and provide your own double pole device to protect cable and chargepoint. Hope that made sense? 😊
@@efixx Does the RCBO you demonstrated in the video provide DC protection if the EV charger has no RCD protection?
I was always under the assumption a car charger needs its own independent double pole isolation. If So a shared RCD wouldn't suffice.
Moving back to the monitored neutral would the overload and over current not work with polarity reversed ?
Great question, I suppose theoretically it would still work but it wouldn't comply with the regs. Also it could cause issues with the electronics in the RCBO. 🤔
The project EV unit that we are due to install says it has a type A BS61009 + 6mA RDC-DD internally then in brackets (type B equivalent). BEAMA says that a type A should not be upstream of a type B RCD, would I be correct in assuming that the internal RCD of the EV is type A so the two RCD devices in series would be the way to go? I ask this because our supply cable needs additional protection due to the installation method. The upstream would RCBO would also need to be double pole. Whats everyones thoughts on this?
the zappi has built in RCD protecting the output, so providing the cable is armoured and not buried it wouldn;t need RCD upstream from the charger, or am i missing something
That is accurate in this case, most ev charge points now don't have RCD protection built in and so would require the double pole protection. 👍
Is a switched neutral truly double pole? Only reason i ask is why dont the manufacturers call it double pole. Thanks Joe
I think to be truly double pole it would need to have overcurrent monitoring on the neutral conductor as well. It's a fine point really.
SPSN. Single pole switched neutral
Is that a nice hole between the CU and trunking I see there Joe Not good 👍 ?
Nope, it's a closed grommet so the underside of the board maintains its IP2X or IPXXB rating. 👍
@@efixx I’ll let you off then 🤣 Great video Joe , not all RCDs/RCBOs have the circuit diagram on them . But that another reason tobe carful.
Please teach us step by step EV installation and open circuit fault detection device
See eFIXX.co.Uk - know how section
That's confused me tbh... The Live part definition clearly states "neutral BUT NOT A PEN Conductor" As TN-CS is a PEN conductor then that is excluded is it not. What am I missing here please?
That Zappi has built in RCD, does it still need another RCD?
Depends on how the cable supplying it is installed. 👍
Any idea what the rationale is for this ? All EVSEs will disconnect both poles of their output on loss of power, so what additional protection does an upstream DP RCD provide when a single pole one will acheive the same result at the output terminals?
Not entirely sure on that one Mike, we'll look into it. 👍
I wonder if the thinking is relating to the wiring to the charging point, rather than the charging point itself. If the consumer unit was wired reverse polarity (rare but not unknown) then the `neutral` at the charging point would still be live even when the circuit had either tripped or had been isolated.
Think it’s for PEN faults/reverse polarity but, as you say, many new devices have these systems inside… but not all!
I would imagine it's to allow for broken PEN conductor faults mainly given that the charger device and EV are likely to be outside the equipotential zone, so touch potential could be a hazard.
There is some mention of the output to the car needing Residual protection with manual reset, whether provided by the charge point or consumer unit. The ICS W7C for example has in-built 30mA/6mA protection and can be set to non-auto reset upon a fault condition. If the cable install doesn't require Residual protection for the circuit then the charge point could be set from 'Auto' to 'non-auto' reset. I don't have my book to hand but maybe someone can clarify this point?
👍👍👍
Why dont do like we on the continent?ALWAYS switch the neutral..In a breaker and in a RCD!
Most of the time it isn't necessary, but you're right it would avoid confusion. 😊
If the charger has a type A rcd built in like the project EV chargers is it ok to just feed the charger off a standard 40a breaker?
Yes but will depend upon the cable route / type of cable.
@@efixx The more i look at all of the info, the more it hurts my head. We’ve recently bought an EV charger (easee one) with type b RCD and pen protection. Can it go in to a BG CUMB40 breaker on an RCD protected board as the charger should handle any DC feedback or overcurrent? The wiring is all along the same wall internal garage wall and clipped?
3m30sec Can't find an MCB in the regs?
Madness, half the petrographic standard I grew up with but lacking. dear me you sure make your sparkies get paid. Still running loops chasing brownouts. Bad enough they don't make us replace all the aluminum in our walls, chasing a new fault monthly.
I've just spoken to an NICEIC tech guy & he said that if a EV charge point has an internal type A RCD & the circuit supplying that charger is buried in the fabric of the building then the RCD/RCBO supplying that circuit MUST be a type B & not type A....Is this correct? In other words, if you have an A in your charge point you must have a B upstream.
I personally haven't heard that, did he give a reg number or an explanation at all? 🤔
@@efixx No, I didn't push him on it but I think I will call back tomorrow & do so. Better still, I have my annual assessment on Friday so will take it up with my assessor
Yeah, I'd be really interested in the answer to that if you can keep us in mind. Cheers! 😊
@@efixx will do. thanks for the good work
Any electrician who does not know that the neutral is a "live" conductor does not deserve to be an electrician.
Shhhaaauppp
Having been, raised, and living in the USA, as well, my father was an electrician growing up: I am deeply fascinated by electrical distribution schema & systems from around the world. Thank you for the videos your channel makes. They provide a plethora of Ideas & Tools for my wishlist.
Happy to help sir! 😊
Hi Joe, so if we had an old split board could we replace the ac rcd for a type a and then fit the charger on an mcb would that be sufficient?? Thank you
yes
@@Neil1699 thanks Neil because our ev needs a double pole but that's covered by the split rcd , cheers mate appreciate it
Neutral is carrying current this has already been discussed
If you used a single pole and a second one straped together would that be the same but just waist of money.
Hm, not sure how that would work as the RCBO would need the neutral, you'd have to run the neutral through the RCBO and the second breaker. Probably would work in theory but I don't think I'd do it that way.
Try buying hagers dp rcbo. £110 if you can find one?
Use Lewden instead! 😊
Lewden: sub £20 from a quick search.
Do I need a DP Rcbo to protect the ev cable,even if the charge point has a Type B Rcbo built in?
What you say is logical but the regulation is badly written in my opinion. Good rules and regs should be plainly written and easily understood otherwise they give way to confusion.
Hm, I think it's written OK, it's the common misunderstanding of what live conductors means that's a bigger issue really. 🤷
Needlessly complicated. Great way to sell “training modules.”
Don't make the mistake of buying an EV. Problem avoided!
Tricky to avoid from 2030
@@efixx not if they fall flat on their face .....
Anti-electric sentiment on a sparkie channel. Interesting.
Yes. Just keep burning stuff. 😕 War mongers who became wealthy selling their oil to idiots will thank you for loving them more than the environment we have to share with them.
@@ciaransherry6021 LOL. 85% of the electricity to power your fancy toy is produced by fossil fuels. What are you going to charge it with if you get rid of them? Eh?