Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Locked Locked
  • Replies 36 replies
  • Subscribers 32 subscribers
  • Views 5987 views
  • Users 0 members are here
Options
You may also be interested in
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

RCD protection in an IT run office

Former Community Member
Former Community Member
Jolly good morning all,


I am currently carrying out an EICR for an IT based company in their head offices.

Looking at the 12way  3-phase distribution board, I can see there are multiple ‘Office Sockets’ circuits labelled up on 32amp MCB’s and not a single RCD in sight. 

To my knowledge, the use of RCD’s is perhaps not required in this type of environment, but just wanted to check your opinions.


Many thanks you’s and I hope everyone is having a splendid dayV?
  • 0
    Well they probably were not required at all when it was installed.

    If they are needed to protect the wiring now depends on the wiring type (armoured, conduits or soft skin like T and E) and how it is routed.

    Also if they are needed to protect the users depends what is plugged into the sockets - if it is equipment that is regularly PAT'd and things are well managed so no risk of any random things that employees bring in from home,  then maybe there is a risk assessment that means the sockets do not need RCD cover.

    Some designs have an RCBO per desk in the floorplate. example  These are less of an issue, the only question then is wiring type.

    If not, perhaps ask to see that RA showing how the absence of RCDS is managed.

    If it does not exist, then either it needs creating, or if it honestly cannot, then RCBOs to be fitted in place of the MCBs.


    Can I ask how long have you been doing inspections ? this is a very common situation.


    Mike.

  • Former Community Member
    0 Former Community Member
    Am assuming this is within the Australian (rather than the UK) context. If so, all outlets are required to feature RCD protection at 30mA.


    (And if in the UK - B7671 would also require same)


  • 0
    While BS7671 requires the same level more or less in new works, what you permit to continue in existing is a different matter - we are not rewiring thousands of buildings overnight each time the regs change.

    Hence risk assessments and partial solutions like RCD protected sockets in the floor plate. (RCD sockets not really accepted by current BS7671, only ones back at the consumer unit)

    Cables in earthed armour and so forth do not need RCD protection, except if supply is TT, then not at 30mA. and you may decide 30mA RCD protection is not needed for sockets in a business setting where what is plugged in is controlled, and the risk has in effect been managed another way.

    You may then defer adding RCDs until you rewire in 20 years time or whatever.


    M.
  • 0
    (And if in the UK - B7671 would also require same)

    Not quite - we still have the option of a documented risk assessment as an alternative to additional protection by 30mA RCD - hopefully we'll keep that option as a 30mA RCD feeding a rack full of IT equipment from an industrial 16A or 32A socket isn't going to end well (and no, hard-wiring it isn't a sensible alternative when non-electrical IT bods need to re-configure it at short notice).


       - Andy.
  • 0
    Joe


    If you do not know what the requirements are for RCD protection you should not be carrying out inspection and testing. This is basic basic stuff that you should already know.
  • Former Community Member
    0 Former Community Member
    John Peckham -


    I am fully aware of the use of RCD’s and the regs surrounding, hence why I asked the question and to get peoples thoughts about their use!

    Not a very helpful comment if I’m honest chap!


    My guess is that at the time of this particular installation, the installers may have perhaps thought that the IT equipment on said circuits, may be at risk of nuisance tripping if RCD’s were fitted, and may have risk assessed this at the time. 

    “61008-1, Supplement 1 reiterates this by stating that an IT system is implemented because it has the advantage that when the first fault occurs, there is no interruption of the power supply to any of the connected electrical loads. However, this "first fault" should be eliminated as quickly as possible.



    The proper use of RCDs in IT systems only makes sense if their function can be proven by measurement or calculation. However, because of the complexity and the difficulty in assessing the structure and expansion of an IT system, it cannot be guaranteed that RCDs will function as intended and therefore their use should remain the exception.”




  • 0


    My guess is that at the time of this particular installation, the installers may have perhaps thought that the IT equipment on said circuits, may be at risk of nuisance tripping if RCD’s were fitted, and may have risk assessed this at the time. 

    “61008-1, Supplement 1 reiterates this by stating that an IT system is implemented because it has the advantage that when the first fault occurs, there is no interruption of the power supply to any of the connected electrical loads. However, this "first fault" should be eliminated as quickly as possible.



    The proper use of RCDs in IT systems only makes sense if their function can be proven by measurement or calculation. However, because of the complexity and the difficulty in assessing the structure and expansion of an IT system, it cannot be guaranteed that RCDs will function as intended and therefore their use should remain the exception.”




     


    I'm confused now - are you talking about an office with lots of Information Technology (IT) equipment on a normal (TN or TT) earthing system - or equipment fed by an unearthed or impedance earthed (IT earthing) electrical supply?


       - Andy.


  • 0
    Hi Joe, when you say "I am currently carrying out an EICR for an IT based company in their head offices" do you mean "information technology" or "isolé-terre"? your last post suggests the latter, but there seems to be confusion in it. What is the earthing system?

    Edit; ninja'd by Andy :)

  • 0
    Agree, "IT system" has two meanings which appear to have become confused in this case.


    Information Technology ? quite likely in a modern office.

    Or an electrical supply system that is isolated from earth, or floating with no current carrying conductor connected to earth. The opposite of a standard UK system in which the neutral is earthed.


  • Former Community Member
    0 Former Community Member
    Olympus - Information Tech. There’s about 50 desks all with split screen monitors and 1 main server room.

Community Rules & Guidelines