For a standard domestic Install, split board with 2x Type AC main switches.
No PV or Car Chargers should this be a C3 or C2?
Thanks in advance
For a standard domestic Install, split board with 2x Type AC main switches.
No PV or Car Chargers should this be a C3 or C2?
Thanks in advance
Yesterday's announcement from the Government: https://www.gov.uk/government/news/government-to-go-further-and-faster-in-becoming-energy-secure
If plug-in PV is being pushed as a way forward, and these are to have a UK standard plug (although BS 1363-1:2023 Clause 5 states that the UK plug shall not be used for connecting generators) then certainly in rented homes, and in flats (rented or otherwise), for the installation to be considered safe, surely:
1. RCDs (RCCBs and RCBOs) for socket-outlet circuits (and upstream distribution circuits if applicable) would have to be at least Type A (because of the way inverters operate, but also for the existing PV inverter standard BS EN 62109-1, this is stated as a requirement for 'pluggable type A' equipment (i.e.. with a standard plug) to be compatible with Type A RCDs; and
2. RCDs (RCCBs and RCBOs) for socket-outlet circuits (and upstream distribution circuits if applicable) would have to be bidirectional (Regulation 530.3.201 introduced in Amendment 3); and
3. RCDs (RCCBs and RCBOs) for socket-outlet circuits would have to disconnect all live conductors (see Regulation 551.7.1)?
The average consumer will have no idea what sort of RCDs they have.
Agreed
They know even less about BS7671 or BS1363
They will be happy until something does happen, it's put forward that the RCD didn't operate and that might have saved a life ... and then all hell will break loose; and it will, of course, be our fault !
Agreed
Therefore Product specification and/or requirement need to deal with it for the UK. Very rare that a consumer will consult BS7671 or BS1363 while to shop on Amazon (other retailers are available)
Therefore Product specification and/or requirement need to deal with it for the UK.
Not sure how the product standard could sort out some of the issues (e.g. incorrect type of RCD/RCBO, unidirectional RCD/RCBO, and single-pole RCBO)?
product standard for balcony solar could mandate an RCD plug for example.
product standard for balcony solar could mandate an RCD plug for example.
Agreed
product standard for balcony solar could mandate an RCD plug for example.
I think that's missed the point ... the RCD protecting other socket-outlets could be:
1. Blinded if it's Type AC
2. Permanently damaged by the presence of a source of energy on its load terminals if unidirectional.
THe danger is then a fault on other appliances connected in the same circuit. In the case of item 2 above, this will persist even after the plug-in generator is unplugged ... so I'm not sure how this could be addressed by the product or its instructions for use?
The average consumer will have no idea what sort of RCDs they have.
Neither will yer average politician.
They will be happy until something does happen, it's put forward that the RCD didn't operate and that might have saved a life ... and then all hell will break loose; and it will, of course, be our fault !
Given that in-service RCDs have a general failure rate something in the order of 7% ... aren't we in that situation anyway?
Likewise when the householder admits they haven't pressed the T button in the last 6 months...
- Andy.
Given that in-service RCDs have a general failure rate something in the order of 7% ...
Are we sure this statistic still current? Yes, I'm aware that, what is now quite a long time ago, there was a study that indicated that statistic ... but there have been a number of developments in product standards for RCDs over the past 25-30 years.
In fact, this site proposes 97 % reliable, with an improvement if the devices are tested regularly: https://www.electricalsafetyfirst.org.uk/guidance/safety-around-the-home/rcds-explained/
Compare that with certain unidirectional devices that are known to fail 100 % of the time if they are operated (including by pressing the test button) with a 230 V source connected to the load terminals ...
aren't we in that situation anyway?
So, no I don't think we are.
In fact, this site proposes 97 % reliable, with an improvement if the devices are tested
I really struggle with that. I suppose that it means that if RCDs are tested and are found to fail, they are replaced, which apparently improves the reliability overall.
3% failure rate. What would you accept for the brakes on your car, for example?
In fact, this site proposes 97 % reliable, with an improvement if the devices are tested
I really struggle with that. I suppose that it means that if RCDs are tested and are found to fail, they are replaced, which apparently improves the reliability overall.
3% failure rate. What would you accept for the brakes on your car, for example?
What would you accept for the brakes on your car, for example?
Surely there are far more [orders of magnitude more] injuries and deaths due to RTAs than electricity-related incidents?
Need I say more?
Surely there are far more [orders of magnitude more] injuries and deaths due to RTAs than electricity-related incidents?
OK, bad analogy.
How about seatbelts? In the vast majority of journeys, they provide no restraint because none is required.
Is there any evidence that RCDs have saved lives over the past 40 - 50 years? Even if electrical fatalities have reduced, it could be for other reasons, so difficult to prove.
Is there any evidence that RCDs have saved lives over the past 40 - 50 years?
It has certainly been stated in expert evidence that RCD could have saved a life if one had been fitted.
And anecdotally if not saved , certainly less badly burnt.
I for example have been disconnected by 30mA RCD, just once ,and was very grateful for it, but still painfully shaken. I have also been saved by the prompt action of a colleague, on something that had no RCDs, but that left my hands with lovely entry and exit wounds that took weeks to heal. Both were very close calls, and once (twice?) in a lifetime events that required many things to have gone wrong so unlikely, and that is for one who gets stuck in more than the average member of the public.
Equally there must be millions of RCDs that are never called upon to trip in anger during their whole operational life (and of those that are, as above a small % wont..)
If we assume my life is worth £1Million (!) then that justifies the cost of fitting about 50K RCDs at say £20 each on new circuits to save me once.
To call someone out to do a replacement, and certainly if that involves a new CU, is probably ten times more expensive, now unless someone gets saved once per 5000 RCDs installed, it is a net loss. We have less than 100 electrocutions per year (*), which is a chance of somewhere between one and two per million, per year, per person.
As such the argument for the additional cost vs benefit on new circuits is reasonably in favour, but the argument for "must retrofit" to existing is probably rather weak.
Mike
** Actually a lot of those electrocutions are touching overhead lines with vehicles and poles, and there is no number of additional domestic RCDs that would help with that so maybe more like less than 1 per million. But there is an additional reduction in fires and so on to offset that a bit.
If we assume my life is worth £1Million (!) then that justifies the cost of fitting about 50K RCDs at say £20 each on new circuits to save me once.
It isn't quite that simple. You really need to do a number needed to treat analysis. The difficulty is that electrocution is (mercifully) rare.
Let us suppose that the death rate from electricity is 1 in a million = 10-6 = 10 x 10-7. We have a new gizmo, which reduces the mortality by half, so 5 x 10-7. Absolute risk reduction is (10 x 10-7) - (5 x 10-7) = 5 x 10-7. NNT = 1/ARR = 2 x 106.
So 2 million new gizmos have to be fitted to save one life.
It has certainly been stated in expert evidence that RCD could have saved a life if one had been fitted.
As I stated earlier.
Considering the time it take to write/publish a BS like BS7671 the lifecycle should start to consider the recommendation of of type B as a minimum for BS7671 Ammendment 5 or 19th edition. Ideal for EV chargers, solar PV (inverters). Caveat could be if it a new design or retrofit
Lets not forget the type F as well for inverter driven loads like washing machines and heat pumps.
I am sure that will be an interesting debate for the JPEL Team for UK Domestic Dwellings
As always there is a grey area
What is recommended/mandated for a New Design
What coding is given on an EICR or In Service inspection and testing. This could be 3,5 or even 10 years after initial install depending on usage. If for homeowner usage it could be 10 to 20 years or untill the sell the property. if the property is PRS (Private Rental Sector) then EIC and EICR are needed from day 1 of the rental agreement. In effect theis makes a 2 tear system. Rented dwellings are more upto date (BS7671) than owner/occupied dwellings.
I am sure you family would rather pay £10 per RCBO in the CU and have you still there and very much alive. The £1Million value is just what bank and insurance companies use to quantify a life. Your family would say your life is worth way more than that and may even be priceless.
It has certainly been stated in expert evidence that RCD could have saved a life if one had been fitted.
A very valid point!
Perhaps more difficult to convince a court that a type A instead of type AC would have made a difference?
Perhaps more difficult to convince a court that a type A instead of type AC would have made a difference?
I can see it would be difficult if the burden of proof was 'beyond reasonable doubt' ... where 'balance of probabilities' applies, it would be easier, especially if the evidence showed an RCD didn't operate when (all things being equal) you would have expected it to do so.
There is plenty of information on the internet that a type AC can/may get blinded so a type A or B or F would be a better choice. A judge or a jourer could look it up and ask their prefered AI engine
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