Dan23584

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Arms
Has anyone else experienced other sparks going nuts for RCD's and thinking they are required for pretty much everything?

I recently did the installation at my local CEF branch and had another spark telling me I should have fitted a dual RCD board! I reminded him that the install was in trunking and conduit ( no less than 50mm issue) and also not in a domestic situation. All sockets were in The office, apart form an outside RCD socket and a couple of sockets in the warehouse that were on an rcbo ( they were near the door to outside).

He still said "well I think it's good practice to fit them in most situations for optimising protection". I just bot my tongue told him to check his regs book and went on about my merry way.
 
Will someone please tell me what far out and away risks were talking about here. these sockets were talking about are in metal conduit containment, so no-ones going to be putting screws or pins through the wiring. Assuming that the ADS is well up to specifications, tell me what risks are we talking about on these IT/computer dedicated outlets....

To be honest I don't think the issue is one of risk, it's more one of arse covering by ensuring that the regs are fully complied with. Common sense and an individual assessment are now banned under the "2012 Follow the book blindly act."

I think the root of some of these dilemmas is the OSG, which whilst handy has dumbed down a lot of the regs and left out some of the "you work it out you're the electrician!" statements. In the OP's case, it's a light industrial/commercial unit. He's taken all reasonable factors into account, done the calcs, made the design, job sorted. Would I have done it in the same way using the same design? Unlikely as everyone works sligtly differently. Neither approach would necessarily be incorrect.

I do think the nuisance tripping spectre is vastly overplayed though. I'm always more interested in the nuisance death issue :)
 
20 years ago I worked as an In Store Technician at Marks & Spenser's and they had a jewllery cabinet that was moved around the store from pillar to post and every time it was moved I had to get involved well one day I said thats it no more moves until I get a RCD safety breaker fitted to this . Well nope one week later manager said move it or I will tell your company to sack you no sorry I said the RCD comes in a couple of days so i was not the flavour of the month so I fitted it not in the unit but at the top of the pole where it plugged in to a lighting track again grief I dont like the look of that box at the top of the pole but hey hoa .

One month later emergency fax came through a 10 year old child was thrown across the shopfloor when he touched the pole it was found that the pole had become live because of it getting moved around the store and strict instructions to disconnect it and fit a RCD to it I faxed back already done this a month ago plus fit the RCD at the top of the pole because if you dont it wont prevent what happened again.

So as I said on the public side of the counter then RCD all the way the funny thing was the manager of my store got a pat on the back for being so proactive but never came up to me to either thank me or apologise for trying to bully me . Funny old world
 
the responsibilities of the electrical designer / installer have become confused with the responsibilties of the building duty holder in this thread.

bs7671 gives multiple options to an electrician to omit rcd's in certain circumstances - no regs are being broken at all if a designer decides to take this route using
a. his engineering judgement
b. a risk assessment on how the installation will be used
c. the clients requirements / wishes.

if rcds are not fitted to computer sockets in agreement with the buildings duty holder then responsibilty for how these sockets are used lie with that person , not with the electrical designer / installer.
therefore if the cleaner plugs faulty vacuum into a socket used for printers and gets a shock then the duty holder has failed to a. supervise & train persons using the installation and b. not have electrical equipment used on the premises inspected or maintained properly - no blame lies with the person who signs the cert.
the OP is perfectly correct not to fit rcd's to circuits that supply IT equipment if the cables are not buried in a wall and will not be used by the general public.
 
the responsibilities of the electrical designer / installer have become confused with the responsibilties of the building duty holder in this thread.

bs7671 gives multiple options to an electrician to omit rcd's in certain circumstances - no regs are being broken at all if a designer decides to take this route using
a. his engineering judgement
b. a risk assessment on how the installation will be used
c. the clients requirements / wishes.

if rcds are not fitted to computer sockets in agreement with the buildings duty holder then responsibilty for how these sockets are used lie with that person , not with the electrical designer installer.
therefore if the cleaner plugs faulty vacuum into a socket used for printers and gets a shock then the duty holder has failed to a. supervise & train persons using the installation and b. not have electrical equipment used on the premises inspected or maintained properly.
the OP is perfectly correct not to fit rcd's to circuits that supply IT equipment if the cables are not buried in a wall and will not be used by the general public.

I make you right I think I had made that clear from outset, the only thing I take issue with Biff is your terminology if I am wrong then correct me, it's for protection of 'Ordinary persons' not the general public, and ordinary person could be an employee and yet not be a member of the public,also even if the cables were buried then RCD protection could be omitted if said wiring was again under the supervision of a skilled or instructed person 522.6.102. on.
ATB
J
 
an employee , whilst in the work place , is not an ordinary person but an instructed person , under the supervision of the duty holder.
but i get your drift JB. ;-)
 
an employee , whilst in the work place , is not an ordinary person but an instructed person , under the supervision of the duty holder.
but i get your drift JB. ;-)

Why Biff ? Under definitions in the regs 'instructed Person' is A person adequately advised or supervised by skilled persons, to enable him/her to avoid dangers which electricity may create.

A 'Skilled' person is someone that has technical knowledge of or sufficient knowledge of electricity to avoid dangers that electricity may create.

How many employees fall in to either category ? Not many I bet ! LOL
J
 
Reading this, Makes me wonder how we have all survived without RCD devices over all these years... We should all be dead or frightened to switch a light or socket on...lol!!

I'm with Dan on this one, far too much reliance on the all singing, all dancing ''Cover All'' RCD devices these day's. They are NOT always required on every circuit and in every situation...

I was thinking the same, I was taught that an RCD (ELCB as they were then) was a secondary protection device and I still consider them as secondary protection seen too many of these things not trip when they should to put total faith in them

Myself yes I would.

Do the items plugged in need PAT? That makes them portable.

What happens when the manager is off work, out of the office etc ? Too many variables in a office to say only one person has to be competant.

Not sure what PAT has got to do with RCD's or are we just trying to cover up for the bad PAT testing that appears to be the norm these days
 
why ?
because the duty holder does not have to be electrically skilled to supervise users of his installation - just to be aware of the potential risks.
because the duty holder is governed by the Electricity at Work Regulations , not bs7671.
 
why ?
because the duty holder does not have to be electrically skilled to supervise users of his installation - just to be aware of the potential risks.
because the duty holder is governed by the Electricity at Work Regulations , not bs7671.

I agree Biff in this case the statutory document takes precedent over the non statutory, not sure it makes them 'Instructed' tho..
but I get your drift ;)
J
 
When I installed the Dado sockets for the our companies office before the staff moved in, I decided to have them on MCB,s and not under RCD protection. There were already existing RCD protected sockets lower down on the wall which I designated dirty sockets, for heaters, fans and the cleaner. All circuits in the kitchen are RCD protected ect.

Obviously we definately have skilled persons looking after the installation, but I'd there weren't, then I would still install in the same way.
 
well i'd expect a "competant" designer to consider any and all regulations that may apply to the use of his planned installation , not just bs7671.
im bowing out of this thread now JB , i cant make my explanations any clearer can i ?
:-)
 
Has anyone else experienced other sparks going nuts for RCD's and thinking they are required for pretty much everything?

I recently did the installation at my local CEF branch and had another spark telling me I should have fitted a dual RCD board! I reminded him that the install was in trunking and conduit ( no less than 50mm issue) and also not in a domestic situation. All sockets were in The office, apart form an outside RCD socket and a couple of sockets in the warehouse that were on an rcbo ( they were near the door to outside).

He still said "well I think it's good practice to fit them in most situations for optimising protection". I just bot my tongue told him to check his regs book and went on about my merry way.
suppose its a `cure all`...1667 n all that lot...lol...
 
Zs value for a 30mA RCD is 1667 .................on any installation


Yep ! Not on any installation only those circuits in an installation that has RCD protection, the 1667 thing is often 'qouted' as a max, if you look at table 41.5 it is clear for any professional to see that this figure relates to a TT system where a satisfactory Zs cannot be achieved, and with the warning that a value> 200 ohms may be unstable,the 1667 should never be used as an excuse to circumvent table 41.3

J
 
Sorry JB not quite get what your saying ...................so if you use a RCD/RCBO on a TN system, you don't use the 1667 value that is clearly stated, but refer back to the values in table 41.3 for MCBs, even though the table since the amendment now refers you to regulation 411.4.9 for the use of RCBOs ( And IMO it should also say RCDs as well to save confusion but the IET like a little confusion) and onto table 41.5 and it's values.

Be it TT, TN the ZS value of a 30mA RCD is 1667
 
Sorry JB not quite get what your saying ...................so if you use a RCD/RCBO on a TN system, you don't use the 1667 value that is clearly stated, but refer back to the values in table 41.3 for MCBs, even though the table since the amendment now refers you to regulation 411.4.9 for the use of RCBOs ( And IMO it should also say RCDs as well to save confusion but the IET like a little confusion) and onto table 41.5 and it's values.

Be it TT, TN the ZS value of a 30mA RCD is 1667

Correct as the wording stands, but my point is, that 411.4.9 clearly states, 'where an RCD is used to satisfy the requirements of max Zs under 411.3.2.2 you MAY apply the values in table 41.5, again my point isn't about terminology, clearly but the fact is you should meet the Zs values in 41.3 and only if you can not you may apply the values in table 41.5
J
 
There appears to be a common misconception, that a skilled person has to be a qualified electrician.
This is not so.
All a skilled person has to have, is knowledge that there is a risk of electrocution or fire when using electrical equipment, and how to avoid those risks.
Such knowledge could be to check for damage and to not use the equipment if any damage is evident.

There are two Statutory documents which relate to workers and dangers in the work place.
One is the HSWA 1974 and the other is EAWR 1989.
Regulation 2(c) of the HSWA requires an employer to ensure: "the provision of such information, instruction, training and supervision as is necessary to ensure, so far as is reasonably practicable, the health and safety at work of his employees;".
Regulation 16 of the EAWR requires: "No person shall be engaged in any work activity where technical knowledge or experience is necessary to prevent danger or, where appropriate, injury, unless he possesses such knowledge or experience, or is under such degree of supervision as may be appropriate having regard to the nature of the work."
These two Statutory requirements make it a legal requirement that any worker or employee meet the requirements to be considered either a 'skilled' or 'instructed' person as defined by BS7671 when carrying out work related duties where electricity may present a danger.
If an employer were to allow an employee who doesn't meet the requirements of BS7671 to be considered a 'skilled' or 'instructed' person, to carry out a work related duty where electricity could present a danger, that employer would be breaking the law.
BS7671 does not provide Regulations or requirements for instances where people would act illegally.
It's considered that if someone is prepared to act illegally, then it is very unlikely that they will at the same time comply with any non-statutory Regulations or requirements.

The requirements for RCD protection apply in the main to domestic installations, because there are no statutory requirements relating to the type of person who would use such an installation.
The first part of the requirement for RCD protection relating to socket-outlets, indicates that the requirement only relates to where the socket-outlets are used by ordinary persons.
The second part indicates that the requirement relates only to those socket-outlets that are intended for general use.
As such the requirement to provide RCD protection for socket-outlets only relates to those socket-outlets that are intended for general use by ordinary persons.
Socket-outlets that are intended for connecting washing machines, fridges, dishwashers, microwaves, cookers, boilers even TVs are not required to be provided with RCD protection.

There are two exceptions to the requirement, and to be honest the exceptions are redundant.
One is for where the use of a socket-outlet by an ordinary person is supervised by a skilled or instructed person.
If the ordinary person is being so supervised, then they are effectivly being instructed and would no longer be considered as an ordinary person.
The other is for where a general use socket-outlet is specifically labeled or otherwise identified as being for use to connect a specific item of equipment.
If a socket-outlet was intended for use only to connect a specific item of equipment, then it would not be considered as being intended for general use, and the exception would not apply.
 
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Nice write up nicely put but I take issue with this..

'Socket-outlets that are intended for connecting washing machines, fridges, dishwashers, microwaves, cokkers, boilers even TVs are not required to be provided with RCD protection.'

Unless the socket is labeled, or suitably identified for a particular item of equipment, to have a socket in a lounge and neglect to RCD it ' because its for the TV' would be very irresponsible, as clearly that socket could also be easily used for another purpose by an 'Ordinary Person', also your above observation would not be valid if the cables were buried ( unless under a skilled..bla..bla )
ATB
J
 
JB, you cannot generally use the skilled/instructed person 'get out' clause in a domestic install, and the socket without RCD protection for use with say a freezer although may be used without an RCD, the supplying cable may still require RCD protection unless it is buried >50mm or ran surface/in conduit, or in an earthed metallic sheath (Ali-tube or armoured etc.).
 
I am reading these posts and the thing that hits me is reality ie electricity via sockets has been here for say 100 years but RCDs have not so ok they can now be mass manufactured at a cost effective price and yes you people who are new to our trade want to RCD everything and so does the Schemies as this raises safety in their eyes so in a domestic situation it is a natural progression the problem as I see it is that we have 2 thoughts 1 is domestic and the other is commercial / Industrial so depending on your background you will want to apply RCD protection to everything or you will want to discriminate between jobs.

For me this is like the "Can I use conduit as an earth" question where someone new says O no seperate earth must apply where poor old 14th edition me would say give me an electrically & mechanically conduit any day
 
I don't see any confusion, he has applied section 411.3.3, and used exceptions a, or b, under this reg, as long as the sockets are under the supervision or a skilled or instructed person ( IMHO this should be noted on the cert ) OR the socket outlets are labelled for use with a particular item of equipment he isn't in contravention of the regs, but I still await the OP's response to my earlier question why he thinks RCD protection only applies to domestic dwellings ?
ATB
J



Good point however isn’t true that whenever we enter into negotiations regarding particulars of an installation & its intended use we as tradesmen have to rely on the word of the client. If the client is adamant that the equipment and installation is going to be used by a certain type of person skilled or unskilled who are we to argue. I guess we can only go by what we are told. To separate circuits accordingly and to suit the requirements is good practise, to use rcds to where they may not be needed is unnecessary.. As most of this stuff is recorded on certs, little notes can be inserted to agree limitations or to highlight an aggreement..

Although rcds are great devices for shock protection originally they were only used in domestic with regard to cables being damaged & additional protection for outdoors via socket-outlets. You be lucky to see them in many commercial and industrial installations. Without disagreeing with anyone I think without the rcd its fine, providing of course your client has informed of the type of personnel that will be using the install.
 
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Nice write up nicely put but I take issue with this..

'Socket-outlets that are intended for connecting washing machines, fridges, dishwashers, microwaves, cokkers, boilers even TVs are not required to be provided with RCD protection.'

Unless the socket is labeled, or suitably identified for a particular item of equipment, to have a socket in a lounge and neglect to RCD it ' because its for the TV' would be very irresponsible, as clearly that socket could also be easily used for another purpose by an 'Ordinary Person', also your above observation would not be valid if the cables were buried ( unless under a skilled..bla..bla )
ATB
J
It may well be considered 'irresponsible' not to provide RCD protection for a socket-outlet intended for use to connect a TV.
However the requirement to provide RCD protection only relates to socket-outlets intended for general use.
There is no requirement to label or otherwise identify any socket-outlet that is not intended for general use.
As such if the socket-outlet is intended for use to connect a TV, there is no requirement to label, otherwise identify or provide RCD protection for that socket-outlet.

Providing RCD protection for the socket-outlet would not necessarily provide RCD protection for cables concealed in walls.
I have not posted in relation to cables concealed in walls, as there are other methods of providing additonal protection for such cables, and there is an exception to the requirement, for when the installation is under the control of a skilled or instructed person.
The exception would not be applicable, if all the workers meet the requirements to be considered as skilled or instructed.
 

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Dan23584

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Nuts for RCDs!
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