Bathroom RCD protection

[pc1966]

No, there was a thread about it a bit ago, but then there are conflicting threads to say that it wont.

One of the IET Q&A had an answer, in a rather convoluted way, saying:

"RCDs to BS 7288 are not recognised for use as an RCD by BS 7671:2018. See Regulation Group 531.3.4.

Clause 1 of BS 7288:2016 states “SRCDs are intended for use in circuits where the fault protection and additional protection are already assured upstream of the SRCD.”

Further, Clause 0 of BS 7288:2018 states the devices are only suitable for additional protection against direct contact, and therefore cannot provide fault protection (e.g. where disconnection times cannot be met in a circuit), nor would they be recognised for additional protection against fire due to short circuits in appliances or flexible cables connected to the socket-outlet or connection unit.

However, there is nothing to stop accessories containing SRCDs to BS 7288 being fitted in electrical installations complying with BS 7671, as they comply with the relevant standards, although as stated the RCDs within them cannot be recognised for the functions of fault protection or additional protection for the purses of BS 7671."

Not having a copy of BS 7288 to look at, the only thing that I can really see from the above is the rather odd statement that they cannot provide 'fault protection', only shock protection. But why that is has not been elaborated anywhere I have seen.

I don't know if it comes down to breaking capacity, etc, but I would be happier with one for shock protection than not, assuming the circuit is otherwise capable of meeting disconnection on the MCB/Zs results, etc.

 

[Mike Johnson]

I might just add it in biro to my copy.

No No No add it in pencil then you can rub it out and modify it when they change their minds........... again.

 

[loz2754]

One of the IET Q&A had an answer, in a rather convoluted way, saying:

"RCDs to BS 7288 are not recognised for use as an RCD by BS 7671:2018. See Regulation Group 531.3.4.

Clause 1 of BS 7288:2016 states “SRCDs are intended for use in circuits where the fault protection and additional protection are already assured upstream of the SRCD.”

Further, Clause 0 of BS 7288:2018 states the devices are only suitable for additional protection against direct contact, and therefore cannot provide fault protection (e.g. where disconnection times cannot be met in a circuit), nor would they be recognised for additional protection against fire due to short circuits in appliances or flexible cables connected to the socket-outlet or connection unit.

However, there is nothing to stop accessories containing SRCDs to BS 7288 being fitted in electrical installations complying with BS 7671, as they comply with the relevant standards, although as stated the RCDs within them cannot be recognised for the functions of fault protection or additional protection for the purses of BS 7671."

Not having a copy of BS 7288 to look at, the only thing that I can really see from the above is the rather odd statement that they cannot provide 'fault protection', only shock protection. But why that is has not been elaborated anywhere I have seen.

I don't know if it comes down to breaking capacity, etc, but I would be happier with one for shock protection than not, assuming the circuit is otherwise capable of meeting disconnection on the MCB/Zs results, etc.

That statement says they cannot be used for fault protection or additional protection. Yet they contradict themselves by saying that they can be fitted. What would be the point of fitting an RCD that provides neither fault protection nor additional protection.
The Connections magazine stated that this omission from BS7671 was an error and will eventually be corrected.
Total shambles as usual.
Because of the controversy surrounding these BS7288 socket RCDs, I personally will not fit them. Which is a shame because they definitely do have a use in my opinion.

 

[DPG]

That statement says they cannot be used for fault protection or additional protection. Yet they contradict themselves by saying that they can be fitted. What would be the point of fitting an RCD that provides neither fault protection nor additional protection.
The Connections magazine stated that this omission from BS7671 was an error and will eventually be corrected.
Total shambles as usual.
Because of the controversy surrounding these BS7288 socket RCDs, I personally will not fit them. Which is a shame because they definitely do have a use in my opinion.

I knew I'd seen it somewhere. Ta.

 

[pc1966]

That statement says they cannot be used for fault protection or additional protection. Yet they contradict themselves by saying that they can be fitted. What would be the point of fitting an RCD that provides neither fault protection nor additional protection.

Ah, because they can provide supplementary protection.

What does that mean in practice? Well we could ask the IET and probably get some equally convoluted explanation as for the original Q&A.

Why they don't just fix BS7288 to provide what is needed I don't know.

Looking at the "PowerBreaker" (Greenbrook) range's data sheet, and the TimeGuard ones (though might be same manufacturer) they claim 1.5kA breaking capacity, but I suspect the 13A fuse would peak current limit to below that even if you have a very high PFC supply.

For example, the 16A BS88 fuse plot I have (as I don't have the same information for the BS1362 13A fuse) has it limiting the peak current to 1.5kA for all PFC up to around 10kA, so it can break as much as it's fuse would let through. Which sounds like a sensible design.

 

[Jm1980]

This seems a crazy situation that really ought to have been sorted.

It seems we don't really have a consensus across the industry about whether an RCD spur to BS7288 can be used to provide protection to a bathroom.
Technically it appears as though it is fine and a departure on the cert is what a lot are doing and indeed being recommended to do via their scheme provider.
It makes me uneasy to use an RCD spur especially as no supplementary bonding, even though I've seen this dozens of times for the purpose of getting rcd protection of bathroom circuits.

On a side note, i look after a factory full of BS88 fuseboards where socket outlets are to BS7288, is it therefore the case that the 18th has made these circuits non complaint/worthy of a departure note, the next time one of the SRCD's needs replacing?

 

[Ian1981]

Extract from a BS 7288 tech sheet

 

[pc1966]

Extract from a BS 7288 tech sheet

Does anyone have definitions for additional protection and for supplementary protection by any chance?

They are not defined in the opening chapter of the 18th regs.

 

[Ian1981]

Does anyone have definitions for additional protection and for supplementary protection by any chance?

They are not defined in the opening chapter of the 18th regs.

Makes you wonder what the point of an rcd spur/socket is when you require an rcd upfront of it anyway?

 

[pc1966]

Makes you wonder what the point of an rcd spur/socket is when you require an rcd upfront of it anyway?

Exactly, if you already have RCD protection then why would you fit one?

 

[Jm1980]

my thoughts exactly, the BS7288 reference you linked Ian doesn't really make much sense to be honest, basically saying you can use them but its pretty pointless because it wont be doing anything that the devices we demand upstream wont be doing.

 

[DPG]

It really does need clarifying in plain and simple terms. I can't believe we are still in this situation.

 

[Jm1980]

Its annoying as it looks like i will have to RCD at the CU end to include the entire lighting circuit which means I'm risking running into pre existing faults that have to be explained to customer.

Who would be happy to use an RCD spur noted as a departure on the cert given that I'm using the RCD as a means to ommit the need for supplementary bonding?

 

[loz2754]

Its annoying as it looks like i will have to RCD at the CU end to include the entire lighting circuit which means I'm risking running into pre existing faults that have to be explained to customer.

Who would be happy to use an RCD spur noted as a departure on the cert given that I'm using the RCD as a means to ommit the need for supplementary bonding?

You could fit an enclosure with an RCD instead of an RCD FCU.

 

[brianmoooore]

If the existing lighting circuits have such a low IR that they would trip an RCD, then that is a C2 fault.
If there is a shared neutral, that is a C2 fault.
I would explain to your customer that fitting the required RCD protection to the bathroom circuits could potentially show up pre existing potentially dangerous faults, that they will need to pay to have sorted.

 

[Jm1980]

Fitting an enclosure outside the bathroom with an RCD in it did cross my mind but aesthetically this wouldn't look very good and it would be a strange setup to have an RCD enclosure half way along a lighting circuit.

In an ideal world Brianmoooore, the entire circuit i would RCD at source and rectify any faults but the loft above has been converted and a chipboard floor layed so i could really be opening a can of worms messing with the entire lighting. You know what customers are like when your there to fit a bathroom light yet trying to convince them you have good reason to have every bedroom rose down and switches off looking for a fault whilst charging them extra.......

 

[loz2754]

Just do an IR test on the lighting circuit and test for borrowed neutrals (more often than not it's a borrowed line at the 2 gang switch for the stairs).
Then you'll know whether an RCD would trip or not.
That's even if there are 2 or more lighting circuits.

 

[Dodd 1]

Basically the IET made a MASSIVE mistake MASSIVE, by not including bs7233 in reg 531.3.6, this is why when the new amendment that comes out in march 2022 will put it right. So the departure they want us to include on our certs is due to there MASSIVE mistake. Carry on using just include there mistake (we should get a refund for this one)

 

[Aaron b]

Basically the IET made a MASSIVE mistake MASSIVE, by not including bs7233 in reg 531.3.6, this is why when the new amendment that comes out in march 2022 will put it right. So the departure they want us to include on our certs is due to there MASSIVE mistake. Carry on using just include there mistake (we should get a refund for this one)

Sparky ninja posted a blog about this issue. It doesn't sound like a mistake or something that will be changed. If it doesn't provide the correct isolation we shouldn't use them as it doesn't give the same level of safety. Please correct me if I am wrong and they are now proposing this for amendment 2.

 

[Dartlec]

Sparky ninja posted a blog about this issue. It doesn't sound like a mistake or something that will be changed. If it doesn't provide the correct isolation we shouldn't use them as it doesn't give the same level of safety. Please correct me if I am wrong and they are now proposing this for amendment 2.

The biggest problem is that there is no one in a suitable position of authority willing to make a clear unambiguous statement on when and when not they should be used. Instead we get carefully worded statements that are more concerned with covering themselves, while not upsetting the manufacturers who make these products, so that they can't be used against them in a court of law.

Either they can be installed in situations where there is no current RCD protection to provide that protection (in which case they should be listed somewhere in the Regs with a clear definition of when it is safe to do so), or they cannot - in which case there is literally no point whatsoever in a 30ma version existing. (perhaps a 10mA one would have some usage where 30mA is already present for additional protection)

The NICEIC's view (for what its worth) does seem to be that they are perfectly fine to install to cover a new small installation such as the one OP describes, as long as they are noted as a departure from 7671, because in their view they meet a suitable level of protection.

There are clearly situations where they are a very handy method, so it's ridiculous that the standards haven't been designed to ensure that an entirely 'official' solution exists.