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Requirements for RCD protection ?

Discussion in 'Electrics UK' started by SimonH2, 5 Apr 2016.

  1. SimonH2

    SimonH2

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    Look closely and you'll see the UPS has a 63A breaker which is actually very under-sized as far as the manufacturer is concerned - though more than adequate for our load.

    The cab with big empty holes has no busbar - it's just a DIN rail to mount the contactor on. The DBs do have blanks in place - at least on the few I've seen.
     
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  3. ban-all-sheds

    ban-all-sheds

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    I wouldn't be keen on RCDs in a server room full stop.
     
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  4. SimonH2

    SimonH2

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    Well that was effectively what I was thinking.

    Well we shall see what happens next. As I understand it, there are moves afoot that will involve some wiring changes in our own unit. If they get the same guy back and he talks about replacing the CU and putting in a split board then there will be some "fairly robust discussion".

    And I heard yesterday that they are getting the local guy in to sort out the unit downstairs with the split supplies. He's a decent and practical guy, so I don't think they'll have the same issues with him.
     
  5. ericmark

    ericmark

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    There are server rooms and server rooms and I would not really be worried with no RCD protection with a halon protected room which requires a permit to work and fire equipment isolating before entry the whole room is secure and the key is a tool so whole room is same as a plant room.

    However I have also been where the server room was the IT departments junk room and occupied on a day to day basis, I know I got into trouble because the sign saying "quarantine area no equipment to be removed without written authorisation, entry to authorised electrical staff only" was missing. Fact it was kept locked it seems was not good enough.

    So as to if RCD protection to a server room can be omitted really is down to who is allowed into the room. We also had a problem showing IT staff were trained to a level that would allow them to work on low voltage. Most had started years ago and had moved sidewards because they were good, and slowly moved up the scale, but had no formal electrical qualifications. Insurance was the problem without some bit of paper to say they had some basic training the insurance considered them as ordinary persons. So they all had to complete a college course can't remember which they did to satisfy the insurance company. Now there is an electrical site safety card "ECS" and that would allow IT people to be allowed into areas where ordinary people were not allowed.

    So rather than jump through all the hoops it may be easier to have RCD protection.
     
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  6. ban-all-sheds

    ban-all-sheds

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    I wasn't aware that RCD protection was about protecting skilled people working on electrical installations.
     
  7. Spark123

    Spark123

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    It isn't, nor would any RCD placed upstream of a UPS protect anyone working downstream of it. I can't remember seeing any RCDs in our racks post UPS. For that reason is there much point in protecting it upstream from a supplementary protection against direct contact POV? Is 240v actually required or will 110v do if there is a safety issue?
     
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  8. ban-all-sheds

    ban-all-sheds

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    Most IT equipment these days, at least the stuff small enough to be single-phase, has SMPSUs which would work on 120V. People might need more PDUs, because of the higher currents involved.
     
  9. SimonH2

    SimonH2

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    But is there a safety issue at all ? I don't recall hearing of hoards of IT people dropping dead due to lack of RCD protection in server rooms.
    I assume we are talking about 411.3.3 ? In which case I can't see it being a hard job making someone an "instructed person" for the purposes of 411.3.3.a, or for making a case for the sockets to come under 411.3.3.b.
    Without special measures I can't see dropping to 120V fixing the "problem". It would need to be 110V centre tapped earth to be a reduced low voltage system as per 411.8 - and that would mean significantly different distribution equipment, most of which is either 3 phase in larger installations, or single phase with single pole fusing in smaller installation (or branches of larger installations).

    A bigger problem in "unsupervised" spaces is people who can't read labels like "UPS maintained circuit - IT equipment only" and plug in a fan heater. Funny enough, the customer never apologised for the rant that came our way about how we must have put some s**t equipment is as the UPS was bleating loudly and must be faulty - that was after someone checked the logs and fount the UPS in bypass due to overload :rolleyes:

    But of course, (as pointed out by someone else) in a situation like that - the UPS may be on an RCD (dedicated circuit with 32A socket), but there won't be effective protection downstream of the UPS.
     
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  11. ban-all-sheds

    ban-all-sheds

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    Customers never apologise for things like that.
     
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  12. Spark123

    Spark123

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    Best thing to do is keep the IT equipment and supplies in locked cabinets or locked rooms so normal persons can't get at them. Then it is up to the management to manage it.
     
  13. ban-all-sheds

    ban-all-sheds

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    True, and for all sorts of reasons, not just electrical safety. In fact that comes w a a a a y down the list of reasons why physical access should be controlled.
     
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  14. PBC_1966

    PBC_1966

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    And even on a very small scale it brings problems allowing unrestricted access. In my previous life I had one client with a small 19-inch rack cabinet I installed on an office wall to contain a small server, PBX system, modems, router, UPS, etc. Knowing the people who worked there (and this with only about four people), my idea was to keep the cabinet locked retaining one key for myself and one for the boss to keep safe elsewhere. But it was insisted that a key be left in the office "just in case."

    You can guess the rest: Calls for help because "we just tried such-and-such" and eventually a call that various systems were shutting down which turned out to be overheating because they'd decided the "spare" space in that cabinet was a convenient place to store all manner of junk.
     
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  15. mapj1

    mapj1

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    if you must have a few sockets for general use, a possible way forward if the wiring is all in earthed trunking or conduit, or SWA, is to fit sockets with a built in RCD but NOT to have one at the circuit origin - that way only defective kit goes off, which is after all the idea.
    Equally one can risk asses the RCDs away in many commercial cases by having a regime of inspection/test or user training.
     
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  16. SimonH2

    SimonH2

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    Only last week I got called out to a hotel I put a wireless system in a couple of years ago. Guests had reported being able to see the office computers which when I left was just not possible. I had my thoughts about what had been done, but "no, nothing's been changed" - yeah right, no one has every changed anything :rolleyes:
    Needless to say, when I got on site, stuff had been changed. Because the hotel weren't prepared to buy a new router back when I installed the wireless kit, and couldn't give me any login details for the routers that were there, nor ADSL details to setup a router again if I blew it's config - I'd had to cascade two routers, one connected to the internet and with all the wireless kit attached, and a second one segregating the office network. Well actually, that's the setup they already had for some unfathomable reason and it happened to be convenient.
    When I got there, one router had been replaced as they now have FTTC (VDSL with an OpenReach modem), and everything had just been plugged into the one router - so yes, all the guests had access to the office network, which was (not by us) setup with zero security on file shares. This wasn't just accidental either - the IP subnet had changed as well.
    It got blamed on a previous manager who "knows a bit about IT" but doesn't work there any more. Still, it's a couple of hours of billable time for me :)

    EDIT: And just for good measure, judging from logs in the WiFi management software, it looks like it was done over a year ago, and a guest mentioned it around Christmas but they dismissed it as "can't be, it was all set up securely" and never looked into.
    Well given how few sockets there are (late 80's build, back when they only expected the vacuum cleaner and perhaps an electric typewriter), in our office it would probably be cheaper to swap them all out that replace the DB.
    Sadly, given that some of our users do nothing to dispel the stereotype of the "la la la can't hear you" attitude to safety and care of equipment, I doubt that any regime of user training could risk assess away the issue. We have a vacuum cleaner with a fairly short lead because during PAT inspection it was found to be worn through to the copper in several places - due to having had the cleaner head "parked" on the cable with the brush bar running - and the "fix" was to shorten the cable to remove the damaged bits. But several times, after having pointed out to people why the cable is so short, I still heard the familiar buzzing sound of the brush bar chewing at the flex while someone is using the hose to remove dust bunnies from PCs - completely oblivious to the racket even after I've pointed it out to them :evil:

    And then there was the time I 'had words" with someone who picked up an insulated driver off my desk, said "that'll do the job" and started to walk off with it. "Excuse me chappie, what do you plan to use that for" was a polite translation of what I said - he only wanted to use it to lever up the seat position locking bar in one of the cars where the normal operating cable had broken :eek: Needless to say, he didn't get to use my driver, nor has he borrowed tools again without asking :whistle:
     
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  17. ericmark

    ericmark

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    I think we have all had the daft stuff happen. But down to brass tacks there are four sets of people we need to satisfy.
    1) Our bosses.
    2) Our insurers.
    3) HSE.
    4) Courts.
    With domestic that can also include LABC inspector and scheme provider inspector.
    It really does not matter what the IET says or BSi, but in the main when IET/BSi says something following it makes it easier to satisfy the above.

    Instructed person to me also means some method to show they were instructed. I have had a class room of workers all with the questionnaire in front of them before before I start, I expected them to fill it in as we went through the instructions and I really did not care, all I wanted was the signed bit of paper to say they had under stood what I had said. I also had some one to translate as I don't speak Welsh.

    Why did I do that, because I got caught out, I told some one what to do, he did not do as told, and I was asked by HSE how I knew he understood me, as they had noted he asked the charge hand to translate all he said in Welsh to English for the HSE inspector. Deep in the heart of Wales most people understand English however they have a problem reversing the order of things to reply. In Welsh it's a lorry red not a red lorry.

    I am sure any IT guy knows enough about electric to keep himself safe. However if they do something daft, we all have the blond moments, then you have to show he should have known better. I and every electrician on site knew the dangers of halon and that the system needed turning off before entry. I had got my permit to work, went to the door, saw the halon was still on, and returned to permit office, he apologised and walked with me to lock off the halon system. Once done he posted the permit and opened the door with the words all yours. Only to find half a dozen guys already working. All had their passes revoked which in real terms meant they were sacked. Not just one guy, half a dozen, seems foremen had told them Eric has the permit. Which in the end I did have it but not when they went in it was never posted until halon was turned off.

    I think it was very unlikely the halon would get triggered so unlikely they would have died. And to my mind one guy gets it wrong blame the guy, Half a dozen get it wrong blame the foremen. But that site had tool box talk after took box talk on site safety and we had been told many times how halon snuffs out life.

    For some one with any certificate even a RAE (radio amateurs exam) to show they have training OK. But some where you need written proof. We have all read the Emma Shaw case and I think we would all have trusted a guy to simply plug in a tester and note the reading the way the electricians mate was asked to do. Non of use would have expected him to sit in the site hut with his mates fudging up the results. However that is what happened and the foremen got the blame. I also think on seeing sparks most would turn of electric before the water.

    Watch your back, fit a RCD even if it will never work because of the UPS.
     
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