I think that's simple enough, given what it 'actually says'. 531.3.6 lists (just) three types of RCD devices that may be used to provide 'additional protection', and also goes a long way to explaining what they mean (in the context of this reg) by 'additional protection' by citing ...So what's your interpretation of 531.3.6?
...AND...411.3.3 Additional requirements for socket-outlets and for the supply of mobile equipment
for use outdoors
In AC systems, additional protection by means of an RCD with a rated residual operating current not exceeding
30 mA shall be provided for:
(i) socket-outlets with a rated current not exceeding 32A, and
(ii) mobile equipment with a rated current not exceeding 32A for use outdoors.
In other words, as written, it seems that it is fairly clearly stating that only one of the three types of RCDs listed are acceptable for the (required) 'additional protection' of sockets, or even for the more general ('recognised', not required) 'additional protection' in case of failure of basic protection or 'carelessness by users'415.1 Additional protection:RCDs
415.1.1 The use of RCDs with a rated residual operating current not exceeding 30 mA is recognized in
AC systems as additional protection in the event of failure of the provision for basic protection and/or the provision
for fault protection or carelessness by users.
You have clearly ignored this explicit statement: "SRCDs are intended for use in circuits where the fault protection and additional protection are already assured upstream of the SRCD." This clearly suggests that I am correct that they are not certified to provide additional protection, making their use redundant in BS7671 terms.I'm not totally clear as to where the quote came from, but what on earth is meant by "....such as phase to neutral"?
That is clearly obvious - NO residual current device can provide any upstream protection. Perhaps it was someone misunderstanding a statement like this that resulted in things getting twisted to create the hearsay which Risteard's heard?
Kind Regards, John
I think you are making the same mistake of interpretation as I recently mentioned, given that it is obvious that NO RCD (whether an SRCD or anything else) can protect anything upstream of it.You have clearly ignored this explicit statement: "SRCDs are intended for use in circuits where the fault protection and additional protection are already assured upstream of the SRCD." This clearly suggests that I am correct that they are not certified to provide additional protection, making their use redundant in BS7671 terms.
Are you talking in terms of BS7671 or in terms of the quote (from wherever) that JohnD posted and about which I just replied to Risteard?So your interpretation is that RCD sockets are not suitable for the additional protection of sockets by RCD?
It's not what is meant. The Standard is explicit that additional protection is not provided by the devices and must be provided separately.I think you are making the same mistake of interpretation as I recently mentioned, given that it is obvious that NO RCD (whether an SRCD or anything else) can protect anything upstream of it.
In other words, I think that the meaning of that sentence is along the lines of
"SRCDs are intended for use in circuits where the fault protection and additional protection of parts of the circuit upstream of the SRCD (if/when required) are already assured by some other device upstream of the SRCD"
Kind Regards, John
As I think we are agreed, I think it's very badly written.I mean in terms of BS7671. BS 7288 is mentioned in the OSG, section 11.4. It seems awfully strange RCD sockets comply with the requirements for additional protection of sockets yet they're apparently not allowed
Indeed it isn't.It may well be that what JohnW2 has put is what the standards writers wanted to convey, but its not what they wrote.
I am one of those others, and have yet to receive any response (which is not unusual). We may have to wait for the DPC of Amd1 (which I imagine must be in preparation).....I believe others have submitted a request to them to consider issueing a clarification on this, but have not had any response.
Nothing's impossible, but it would seem a bit odd that the BSI would (in BS 7671) be party to "trying to eliminate RCD accessories" at the same time that they were publishing a new Standard relating to RCD accessories!The other alterative is that they are trying to elininate RCD accessories, I think they are a UK only thing, I suppose its not beyond possibility that they are being made pointless in order to allow further harmonisation of standards
The other alterative is that they are trying to elininate RCD accessories, I think they are a UK only thing, I suppose its not beyond possibility that they are being made pointless in order to allow further harmonisation of standards
It's factual "hearsay" whether you like it or not.
I don't have a copy as I can't afford one.
It's not what is meant. The Standard is explicit that additional protection is not provided by the devices and must be provided separately.
??... To be fair, he was a Buffoon, which I'm sure doesn't apply here.
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