Nuts for RCDs!

[Engineer54]

Who said they were ? The OP was seemingly criticising another sparks interpretation of the need for RCD protection on his installation, as stated its his call, that doesn't make the other guy completely wrong !
J

Eh, ...i'm making a general statement here, nothing more nothing less!!!

 

[Fin170]

Kind of makes you wish 'specialised' sockets were more easily available, like the ones with the T shaped earth pins so you could fit them to computers for dedicated socket circuits and avoid this kind of situation

 

[Jimmy Boy]

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.

Dan I really am just looking for reasonable discussion not an argument,but where would have you pointed him to to look in the regs ? It's the bit about your installation not being 'Domestic' that I can't square the circle with in my head ? 411.3.3 states the reasons and exceptions, and you have decided to apply one or both of the exceptions in that reg, again I have no issue with that, your call, are you saying 'ordinary' persons can't be found in a non- domestic building ? so that's a given ?
J

 

[Jimmy Boy]

Kind of makes you wish 'specialised' sockets were more easily available, like the ones with the T shaped earth pins so you could fit them to computers for dedicated socket circuits and avoid this kind of situation

They are readily available I have used them on many occasions , problem being of course is that all IT comes with their own moulded plugs and most people don't take kindly to having them cut off !
J

 

[Deservices]

As long as regulation 411.3.3 is met then what you have done is perfectly fine.

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Just because it is in a office area and may nuisance trip is no reason to by pass the regs.

At what point have the regs been bypassed?

 

[Plonker 3]

I never directly said that it had.

I would of done the same in a office environment, last thing they would want is all there computers going down just because a bulb goes in a light, or somebody plugs a dodgy item in a socket in warehouse. Looks like you did the best protection for the job in hand.

Makes it sound like there was no other way to carry out the job, therefore the regs could have been ignored?

 

[Deservices]

I never directly said that it had.



Makes it sound like there was no other way to carry out the job, therefore the regs could have been ignored?

He provided addition protection where he had a idea other people may plug things in ie near the rear door and In the warehouse. Adding another rcbo to the office sockets would of made no difference to the cost(parts supplied by CEF) so I'm assuming CEF asked for no rcd so as to get no nuisance tripping, in which case would of also had a competent person to see that the sockets were used what what is intended. Ignoring the fact that everything is surface mount and in conduit.

 

[Plonker 3]

He provided addition protection where he had a idea other people may plug things in ie near the rear door and In the warehouse. Adding another rcbo to the office sockets would of made no difference to the cost(parts supplied by CEF) so I'm assuming CEF asked for no rcd so as to get no nuisance tripping, in which case would of also had a competent person to see that the sockets were used what what is intended. Ignoring the fact that everything is surface mount and in conduit.

Now I am not getting involved in a argument, but it is down to interpretation. IT equipment will leak to earth therefore causing a RCD/RCBO to trip if to much is installed on one circuit. This is what the OP wanted to avoid. Now the sockets wont be used or constantly monitored by a skilled person. As to do that would be bloody expensive to employ effectively retail assistants.

The customer has not stated they dont want the sockets RCD protecting as again the OP has said he has done the design, install and testing.

So the only way I see it possible to do this would be too.

A. Work out earth leakage of each item of equipment
B. Install enough circuits so that none reach the limits of nuisance tripping
C. Install each circuit on a RCBO

 

[Deservices]

So your saying it has to be RCD protected, even though in conduit and no mobile items will be plugged in? Only the office manager has to be deemed competent to know how to take care of the sockets, they don't have to be a electrician to be deemed competent to know what should be plunged in or not( I may be wrong on this point)

 

[Plonker 3]

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.

 

[Deservices]

Now I am not getting involved in a argument, but it is down to interpretation. IT equipment will leak to earth therefore causing a RCD/RCBO to trip if to much is installed on one circuit. This is what the OP wanted to avoid. Now the sockets wont be used or constantly monitored by a skilled person. As to do that would be bloody expensive to employ effectively retail assistants.

The customer has not stated they dont want the sockets RCD protecting as again the OP has said he has done the design, install and testing.

So the only way I see it possible to do this would be too.

A. Work out earth leakage of each item of equipment
B. Install enough circuits so that none reach the limits of nuisance tripping
C. Install each circuit on a RCBO

He would also do the design based on what they wanted. But as he's not stated they didn't want RCD protection, I would also of fitted one if not been requested not to. but of told them possible trips and adjusted needed ie maybe run a few radials.

 

[Jimmy Boy]

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

 

[Deservices]

The term mobile is for a item that is moved while it is plugged in ie floor cleaner lawn mower not commuter monitor.

 

[Jimmy Boy]

TBH I think it is going a little off track, the question is, will those sockets be used or be LIKELY to be used by 'ordinary' persons ?..answer yes, then apply the regs RCD them, answer no, then use the exceptions in the regs, but, and here is the rub, I can foresee very very few office situations, where you can reasonably guarantee that no one other than those skilled or instructed persons will use those sockets, the cleaners come in a ten at night use the sockets, or some maintenance man, too many variables for my liking but as I say it's down to the signatory ! It's his head on the block if it goes pear shaped !
J

 

[Engineer54]

Far too much being read into this, ...exactly what are you expecting to go wrong, if and when the instructed person is out of the room/office?? He has stated the dedicated outlet for the cleaner has been RCD'd??

You simply can't cover every single possibility of usage of a circuit, that is out of any electricians control. As far as i can see there is nothing wrong with the OP's installation. ...And no he won't have his head on the block!!

 

[dagrat]

I agree with Engineer 54,I think that the regulation as it stands refers to installations that come under the control of a competent person, and therefore does not necessarily refers to persons using the computer.
One reason the RCD regulation is relaxed in these situations is because it is assumed (for example) that any drilling in these locations will only be undertaken by a skilled and competent person. So no probs

 

[oldtimer]

Good discussion guys and me thinks we are missing the point as we are all lead to believe that RCDs were introduced because an MPs daughter was sadly killed but me I am more cynical than this I think because RCDs became more economically viable the MPs daughter was used as a vehicle for interested parties ie the Scheme providers to strengthen their position within the industry and at the same time they get to ride on the back of improving safety . Also they thought via Part Pish they thought they could control the domestic environment but stayed well clear of trying to force it on the commercial and industrial sector. Remember the you cannot back date the regs but you put it in such a way that if you make changes then you need to apply them.

Now as for CEF being in the industrial and commercial class well yes but there is one problem their when you walk in they have a lot of lighting displays so in a sense they have to be RCD protected even although the majority of the people on the customer side are electricians they have to be treated as Joe Publics

 

[smu_diddly]

I don't think cef will have enough IT equipment to cause an rcd to trip, you would need like a huge office full of them to produce enough leakage to trip. If all other circuits are in conduit then fine leave the rcds off them but stick an rcbo on the sockets. I wouldn't take the risk.

 

[imago]

exactly what are you expecting to go wrong,

Well they used Proteus gear, so .........

 

[Engineer54]

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....