Disagree. Electricians should already know or at least have a suspicion that using an RCD on current coming through from the load connection of an RCD back through the RCD is something that needs to be explored further. Additionally, if using solar panels or batteries, the electrician should be keeping themselves up to date by undergoing specialist training courses in these areas. They are available. It is your responsibility as an electrician to recognise when you are working in new territory on something that is outside of your sphere of knowledge, something that was not part of your original training in your apprenticeship, and it is *_your_* responsibility to address that knowledge gap. The regs are not a substitute for training. The problem is electricians are using the regs as a step by step 1diots guide because they can't think for themselves.
We have been using Inverters on motors for many decades and we are well aware regarding the issues of blindsiding rcds, unfortunately the regulations are written and compiled with profit in mind, the more ambiguous the more they make on guidance notes and books that follow, we have a battle here of honest working people been used as a cash cow for the overseers who claim to be protecting the industry and bringing safety levels up, what we have seen is a dumbing down of education, a dumbing down of electrical courses and a increase in confusion over poorly worded and constructed regulations. I remember when the regs were clear, I remember before RCD's were part of most domestic circuits and I remember when fuse-boards were made of wood, strangely all these new regs be they rcd cover or metal boards etc have not dramatically decreased the fatality rate because regulations do not stop DIYers and bogit and scarper companies from creating the death traps that have always haunted our industry.
@@deang5622whilst I agree with you to an extent. I also don't see why you're absolving the IET from their responsibilities.... Or should we have no wiring regulations at all?
It seems extraordinary that this bi-directional issue of RCDs, MCBs and solar systems is only now being addressed. I remember mentioning a possible issue years ago and was told by those wiser than me that the devices would work either way without trouble. How can the IET not have addressed this when solar first became a common installation? However, as others have pointed out, the grid tie inverters should drop out on loss of grid anyway...hmm.....
Depends on the design but from what I can tell by looking at several datasheets for the ICs that are used in electronic types, the trip current coil is only kept in the high state until the imbalance in the CT is removed, ie the condition is not latched until the circuit itself looses power. Regardless of which side the supply is on, when (if, ie the device is not mechanically faulty) the contacts are opened current through the CT will cease and the trip current reduced to idle (in the case of supply on the wrong side) or completely removed (in the case of supply on the correct side). A similar thing applies for magnetic types but since the trip is powered straight off the CT if the magnetic type does not switch the neutral it has the potential to continue to pass current through the coil if there is abnormal current flow due to a neutral/earth fault. No electronic 'directional' RCD should burn out the trip coil with supply on the wrong side, when it is acting on an actual earth fault. If anyone can point out an electronic RCD or a neutral switching magnetic type that can actually burn out the trip coil or the SCR (or what ever it is in the particular device) in an actual earth fault condition, where the RCD does not have an existing mechanical failure that prevents operation, that'd be really interesting to look into. The rub is the test button. Hold the test button in with supply on the wrong side and you've got a problem as the trip coil current will remain high until you release the button since the imbalance in the CT remains. Bi-dir types not only break line and neutral they also break the test circuit itself.
@@retrozmachine1189 So what is the IET getting it's knickers in a twist about? Is it just down to lobbying by manufactures so we all have to buy new devices?
"Sorry madam, your consumer unit needs to be renewed as you have no RCD protection" Then "sorry madam, yes you have an RCD but its the wrong type as you have LED lights so thats another £100+ please." This industry is becoming a f**ing joke.
No, its not like that. Its because with the more complicated electronic, simple protective devices become insufficent. Its like a load bearing beam. For simple loads it might work well to hold lets say 10 ton. But once you put a concrete vibrating machine that weights 9 ton, the load bearing beam might become insufficent, even if the load rating is fulfilled, just because the vibration adds additional dynamic loads that could "exceed" its rating, even if it not does it on paper. Same with for example resonance. And in a similiar way does electricity works. When you get more "complicated" loads, the protective devices we used for years does no longer "work", and needs to be upgraded.
They Dont know their arse from their elbo and we have to tell the clients it's more money Just like No DC isolators one for each string now and batteries in lofts even if manufacturer is happy with them being in loft and securely mounted 😂😂😂
In practice an RCBO or RCD getting powered from "the wrong side" by the solar or battery system should only do so until the inverter realises it's lost the grid (as the trip coil will have done its job). Once it detects loss of supply it should shut down to prevent backfeeding (within 500mS from what I've read so far) which will kill power to the coil. Question is, should a trip coil be able to handle half a second's worth of power?
Quick question from a viewer. Storage heater Consumer Units. When upgrading from cartridge fuse to breaker type boxes, should a customer be asking for MCB's or RCBO's? TIA
EV chargers may be exempt from the latest cyber regulations, but they are already required to meet The Electric Vehicles (Smart Charge Points) Regulations 2021 which has it's own cyber security requirements and is in law.
I watched this a week or so ago and been thinking about it since. The issue is the trip coil staying energised and burning out. As 99% of solar devices are grid tied ( even with battery storage) then As soon as the Rcd trips then the solar inverter will shutdown ( due to the loss os the power grid) therefor there won’t be any power on the load side of the Rcd. Not saying it’s not necessary to fit bidirectional units but there will be loads of sparks giving these a C2 on inspections. Have I misunderstood this 🤷♂️🤷♂️
When is ratified can you do a correct design video. As a home owner i can then check what I've got and know what an electrician should install. I ask this as my install is now ten years old and hence likely to be not up to standard. Thanks for the videos keep up the good work
I have seen some inverters add a DC component to their grid feed. Not sure how to prevent that. AC and DC rcds will not trip, as the DC is in a perfect loop back to the substation.
2:15 - No its incorrect. I readed up on the law. It will be illegal to SELL (eg, retail) things that aren't compliant. This includes installing, IF you are selling the item with the install. HOWEVER, you may install a consumer supplied item, even if the compliance end date is expired or is non-compliant according to the cybersecurity law. So its not the installation itself that is illegal, but the sale of the item. A consumer may install vulnerable products in their own home aswell (for example, smart plug-in sockets that you connect between socket and plug). (compliance end date is a specific date set by the manufacturer, where the item may no longer be sold. Selling items past the "sell before" date is a criminal offense, as a item is considered non-compliant after that date, like expired meat food) They even have a exception for "Used or second hand products", meaning, anything that the installer did not buy, is not in scope for the legalisation. As soon as the customer opens the packaging on the product, the product becomes "used or second hand" in legaliese, meaning, a electrician can install a heat pump, solar inverter, smart switch that the consumer bought and unpacked.
It should be fairly obvious that in a bidirectional situation, care should be taken to refer to the manufacturer's specification as to whether the device is suitable.
The regs are important but have become a massive money making scheme against the industry, they are purposely ambiguous so further guidance and literature can be profited on, I am sick and tired or badly worded regulations leaving so many to tumble into non compliance. Also it about time we were able to purchase amendments in the form of additional pages for the current edition of the regulations instead of been forced to scrap you previous copy and buy another full regulations book with yet more ambiguous additions they can then push out guidance books on. There is a clear focus on profit margins, if they renewed and structured the regulations with common sense and foresaw these clearly obvious issues thus worded and compiled the regulations to be less ambiguous and give better clarity then the Electrical industry wouldn't be forking out all the extra costs, unfortunately short sightedness and additional literature makes millions in turn over so I cannot see this been resolved any time soon, the truth is if I am wrong then you have some very incompetent authors of the regulations who's jobs should be questioned.
@@efixx Well I will definitely be shocked to see that, these 'oversights' have occurred numerous times over the many yrs and guess who's pocket it hits normally.
Strongly think that if manufacturers provide advise which lead a designer or installer to protect a energy generation device on a uni directional protection device without highlighting consequences then they should be liable for misinformation and not making the distinction between bi-directional and uni-directional devices. See that solar and battery decides have been around for decades. This should have been addressed in Amendment 2 or sooner
Does this mean that my 12 year old solar panel installation may be dangerous? I had a new main consumer board installed at the same time by a registered contractor. We have had a couple of 'trips' due to fault in our oven but otherwise all seems OK. Should I have this problem checked out?
It's hard to say without looking, it's recommended that periodic inspection and testing of electrical installations take place regularly anyway, so it might be worth getting it checked out. 😃
Regarding the unidirectional RCDs with solar PV installations, doesn't the G98/G99 "loss of mains" protection mitigate this issue? It doesn't help that not all manufacturers produce bi-directional RCBOs. (E.g. Fusebox) I'd also say that I don't particularly like the solution of adding a third pole to the contactor - I'd rather the coil could be powered continuously without burning out as this is meant to be a safety device and therefore should be robust, but a trip coil with a poor duty cycle doesn't fill me with confidence.
Trip coils are designed for fast operation to clear the fault quick enough, but in doing so, it makes the coil short term rated. If you design the coil for continuous operation, then it slows down, and the fault persists for longer, giving danger to the person / equipment you are trying to protect.
@@three-phase562 The physics limitations are a fair point, but there are other ways they could make it more robust as a unit. For example, you could go down the pinball flipper route where the current to the coil is reduced after the initial actuation. (This could be PWM rather than an actual current limit) Another option is to only output a pulse to the coil so that it doesn't try to hold it. You could also implement a temperature limit for the coil, either an actual thermistor or a bi-metallic limit switch. An argument against this may be for cost or complexity, but I feel that given we now have AFDDs this is no longer an issue.
Use neutral switching RCDs (really you should be using them anyway in my opinion) and also switch the test button circuit. That way there's no additional complexity to the electronic ones (PWM as you proposed later), and it would be a complete solution for magnetic types too.
I did an EICR the other day, beautiful property excellent wiring. The Solar PV install on the face of things was good but the M2 Brand enclosure for the AC side was using a type A RCD which failed to trip under test conditions or with the test button. Instant C2 - not to mention the T&E the installers used was gland in under the bus bar but instead of taking the 2 minutes to dress the cable in they'd twisted it going past the bus bar causing it to wear through the outer sheath and expose the inner cores. Completely support this amendment. They should ideally be installed in such a way to never need the RCD protection or manufacturers need to properly provide a purpose built off the shelf solution.
@@persona250 An M2 Brand 40Amp Double Pole 30mA Type A unidirectional RCD. And it has failed in exactly the same way. BS7671 Regulation 712.531.3.5.1 (iii) specifies Type B RCDs for use on the out-put of PV systems, unless the manufacturer states that it is safe to use Type A or F RCDs. Evidently it was not safe in this instance to use a Type A RCD that is unidirectional.
@@travoltasbiplane1551 It does not state on the manufacturers literature that it is bidirectional. More so that it has failed in the way a unidirectional RCD would. Taking into account how it has failed and literature the only deduction that can be made is it is not bidirectional and not suitable for the installation. I stated the model because I thought originally (like you appear to) it was a one off failure and no national solar installation company with multiple installs would have made the mistake.
But on the RCD topic, not all manufacturers make bi-directional RCDs/RCBOs. Seems like a cop out for them while we now have to go clear up the mess across any installs and charge for it or simply do it under warranty. Bet the new RCBOs will be expensive to buy too. Can't see the cowboys going back !
I'm not sure really, for us it is mandatory to fit a shunt (fireman's switch) in the DC within 1.5 metres of entry to the property, this acts as a fast disconnect, slow reconnect for each string, I get that it could take one second but surely an RCBO coil is rated for that
Nothing against bi-directional RCDs, happy about that, but playing devil's advocate - any grid tied micro generator stops supplying power if the grid is lost, eradicating the need for such an RCD / RCBO anyway, right?
Interested to see how or if marking is applied to devices such that it is possible to identify bi-directional compliance. Having to refer to manufacturers data sheets in conjunction with date codes on the device isn’t really going to cut it. Have the IEC even thought of this or is the IET/BSI leading or lagging the process? P.S. My efixx goodie bag has arrived from my win earlier this year. Many thanks!
I'm my experience. If it's not explicitly stated in the datasheet then there's every chance it won't be so you need to contact the manufacturers. Endless isn't it.
@efixx has Gordon elaborated about the issues he has had with smart meter as mentioned in video. I live rural and we have issues with not being able to take up good tariffs because we do not receive GSM signal. I also use a economy 7 meter which I want to keep.
Does anyone recommend a DIN-rail mounted, POE switch, that can take power directly from the consumer unit; most I have found want power supplied by another product, and not many of them are compat. with bell transformer voltages... Mostly to make the under-stairs cupboard much tidier!
I wouldn't recommend combining your network cabling and 240v consumer electrics together. You need minimum separation distances between mains voltage circuits and ELV and network cabling. Network cables should not even be routed through the same holes in walls/joists as power cables, or near to consumer unit due to the magnetic interference that can be caused... Run a network switch from a socket outlet with type 3 surge protection, which is on its own dedicated 16A radial circuit with RCD protection or a 16A RCBO. This will help reduce network outages if there are other electrical faults and it will also shield from transient over voltages or 'dirty' sine wave AC coming in. Use shielded cat6 cabling to minimise EMI and packet loss. Keep network cabling routes ideally at least 5-10cm away from 230v cables.
Hm... So all the manufacturers on JPEL/64 didn't note this? Throw them all out! They should have to replace all the unsatisfactory installs at their expense, because this is just complete incompetence! David CEng.
The cynic in me might suggest that these things have a habit of coming to light only when a suitable product range is imminent. Until then they are quite happy to sell the products: with the ultimate responsibility for its installation (in the correct manner) falling with the designer/installer.
I guess the exception to EV chargers and smart meters means they are all liable to hacking. First thing I intend to do when I buy an EV is figure out how to disconnect it from the matrix. Dumb is always better in the long run. No updates to brick your devices/car as happened with my brother's cords update. Had to take it to dealer to be sorted.
As a non-electrician who is interested in these things (so please be nice if I'm making a stupid comment) I'm wondering why this is an issue? For any G98/G99 compliant grid connected installation wouldnt the tripping of the device (RCBO, etc) cause whatever inverter was between the device that tripped and the solar array/batteries to shut down due to lack of a grid phase signal to syncronise with, so stopping any power being fed to the output of the RCBO that could burn out the solenoid coil? Please could someone explain what I am missing?
@@VinoVeritas_ OK, so literally 0.5 seconds is enough time to damage the coil, I was assuming it would be minutes or even hours....thank you very much for explaining. Glad I have got RCBO's....anyone with RCD's and solar is far more at risk as all the MCB's on the solar side of a high integrity board could be left unprotected as any time any of the circuits trips the RCB would get another 0.5s of charge through the solenoid.
@@VinoVeritas_ They are old Wylex NHXSBS1B16's which I think are only single pole from memory unlike the newer miniature versions which switch live and neutral, so cant imagine they will be any good. All my solar cables are either surface fixed or running through the floor so I dont actually need RCBO protection on the solar circuit, but I had my Consumer unit upgraded after my solar was installed due to nuisance tripping caused by DC leakage from the solar panels added to all the other existing house leakage currents occasionally tripping the single 30ma RCD that served the entire CU at that time. I've submitted a scheme to the DNO for 3No 5000VA Victron Multiplus 2 inverters and 30kWh of LifePO4 batteries and if that gets approved I will be getting the whole house wiring reconfigured anyway
@@bernardcharlesworth9860 Can you demonstrate a single standard that MCS has produced? Which books are mandatory for all MCS accredited solar PV installers to have?
Even if it is hooked up incorrectly installation tests should identify that not all is right. Press and hold the test button for a second and check for incorrect behaviour, including repeated firing of the trip.
Why would they pay you to remove them, they could just not use them for free. I've actually had a huge spike in the number of chargers I've been installing.
Cant work out if this is a blessing in disguise or not, I’m just about to do my BS7671-2, is worth waiting now? 😫 wont help being £90 down for a book though 😂 waam waaam waaaaaam
