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Use of RCD protection in industrial and commercial installations

Hello All

We all know the benefits of RCD protection and how the regulations are changing regarding domestics. I am constantly being asked if RCDs are required for normal switched socket circuits in industrial installations apart from the obvious use of RCDs for areas likely to cause a reduction in resistance (sockets that could conceivably be used out side). So are RCDs required for general office circuits, for dedicated IT equipment (computers etc), work areas such as clean dry packing areas and so on.

Given RCDs require testing regularly and the results recorded which causes disruption to production equipment, IT equipment, Data centers etc are RCDs really required especially if they are installed within steel conduit or steel trunking on walls or under floors?

Any advice welcome

Andy

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0 tattyinengland over 4 years ago

Hi Andy H.

I see your post related to more IT systems but still, I have, after much head bashing and trying desperately to find ways not to fit RCDs when adding to existing commercial systems - come to the conclusion that there is no way to avoid fitting RCDs other than with the use of a Risk Assessment to say that it is not required to be fitted. Which no one is willing or able to take responsibility for and do. So as shown below I - too- dance around the issue on occasion.

Even in a server room when we build one - usually these days smaller than they used to be in offices - a risk assessment is the only way around not fitting an RCD I think. I commonly fit RCBOs that supply a commando socket - that supplies the UPS. This is probably impractical in bigger situations such as yours I'd guess............If there are UPS involved in your situation then that could be taken into account too. (How well would an RCD work down stream of a UPS?)

In your situation I'd get the M&E Consultant to draw up a risk assessment to avoid fitting RCDs - every one knows its sensible, but someone needs to take personal responsibility for this decision, Consultants are usually happy to charge to take on this sort responsibility..... usually with so many caveats that it means its not their responsibility at all if something goes wrong - the client has not followed the caveats, hence its the clients' responsibility. (You may be, said consultant - in which case this is all a lot of waffle.............)

Small example of my issues: commercial offices and underfloor bus bars supplying electrac floor boxes - Its common practice to RCD protect the underfloor bus bars especially in a CAT A fit out, and I come in on the CAT B fitout stage - so arrive to find the underfloor bus bar 30mA Protected and every floor box with just double sockets.........but I hate this practice as a single small fault will knock out multiple desks and - over time - with more staff being crammed onto a floor space, I have seen 30 desks on a single RCD protected underfloor bus bar...........common practice for me - a single bus bar will supply 10 desks at the most if on a single RCD protected Bus bar (So I recommend we fit more bus bars - which is good for me, but often the client is less willing and wants to find another way to utilise the bus bars he/she has now in this beautiful CAT A space......... Either I fit RCD sockets in the floor box or what I do is I get the client to assure me that each desk will be fitted with its own RCD in line to the desk sockets. I don't then need to fit RCD protection to the underfloor bar. BUT......Each floor box has 2 x DSSOs in it that are not RCD protected. This then becomes a problem for now as it does not forfil the letter of the regs with regards to floor box sockets. If I fit RCD sockets it becomes a problem for the future - maintenance and inspections. Often I need to do additions or shuffling around of the desks to accommodate desk moves/staff.....

These floor boxes are - when I do them - always located centrally under the desk and not really easily accessible for general use by other than the desk user. Essentially this IS a risk assessment done by me but I have no control over future use of this installation so I'm not about to formalise this statement in a risk assessment that I'm going to sign...........(This is a good design, I Believe, and the one that I recommend if we cant fit tap off leads such as the electrac IAB Intersock range or Rotasoc for example as long as lots of RCD protected "cleaners sockets" are also scattered around, but someone has to Risk assess this and put it into some kind of formal document, which never ever happens.) I have now resorted to adding this caveat to the EIC Comments section when applicable.

The above scenario is quite common because the client often takes on a floor space populated with existing floor boxes

Something along the lines of: The Client has stated they will ensure that RCD protection is afforded to each desk with the use of an in line RCD between floor box and under desk sockets for example and these floor box desk supply sockets are not for general purpose use. Cleaners sockets that are RCD protected and readily accessible, shall only be used for general purpose use.

I'm not sure how legally exposed this leaves me or the legal implications of this sort advice so Id treat it with caution.
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0 tattyinengland over 4 years ago

Hi Andy H.

I see your post related to more IT systems but still, I have, after much head bashing and trying desperately to find ways not to fit RCDs when adding to existing commercial systems - come to the conclusion that there is no way to avoid fitting RCDs other than with the use of a Risk Assessment to say that it is not required to be fitted. Which no one is willing or able to take responsibility for and do. So as shown below I - too- dance around the issue on occasion.

Even in a server room when we build one - usually these days smaller than they used to be in offices - a risk assessment is the only way around not fitting an RCD I think. I commonly fit RCBOs that supply a commando socket - that supplies the UPS. This is probably impractical in bigger situations such as yours I'd guess............If there are UPS involved in your situation then that could be taken into account too. (How well would an RCD work down stream of a UPS?)

In your situation I'd get the M&E Consultant to draw up a risk assessment to avoid fitting RCDs - every one knows its sensible, but someone needs to take personal responsibility for this decision, Consultants are usually happy to charge to take on this sort responsibility..... usually with so many caveats that it means its not their responsibility at all if something goes wrong - the client has not followed the caveats, hence its the clients' responsibility. (You may be, said consultant - in which case this is all a lot of waffle.............)

Small example of my issues: commercial offices and underfloor bus bars supplying electrac floor boxes - Its common practice to RCD protect the underfloor bus bars especially in a CAT A fit out, and I come in on the CAT B fitout stage - so arrive to find the underfloor bus bar 30mA Protected and every floor box with just double sockets.........but I hate this practice as a single small fault will knock out multiple desks and - over time - with more staff being crammed onto a floor space, I have seen 30 desks on a single RCD protected underfloor bus bar...........common practice for me - a single bus bar will supply 10 desks at the most if on a single RCD protected Bus bar (So I recommend we fit more bus bars - which is good for me, but often the client is less willing and wants to find another way to utilise the bus bars he/she has now in this beautiful CAT A space......... Either I fit RCD sockets in the floor box or what I do is I get the client to assure me that each desk will be fitted with its own RCD in line to the desk sockets. I don't then need to fit RCD protection to the underfloor bar. BUT......Each floor box has 2 x DSSOs in it that are not RCD protected. This then becomes a problem for now as it does not forfil the letter of the regs with regards to floor box sockets. If I fit RCD sockets it becomes a problem for the future - maintenance and inspections. Often I need to do additions or shuffling around of the desks to accommodate desk moves/staff.....

These floor boxes are - when I do them - always located centrally under the desk and not really easily accessible for general use by other than the desk user. Essentially this IS a risk assessment done by me but I have no control over future use of this installation so I'm not about to formalise this statement in a risk assessment that I'm going to sign...........(This is a good design, I Believe, and the one that I recommend if we cant fit tap off leads such as the electrac IAB Intersock range or Rotasoc for example as long as lots of RCD protected "cleaners sockets" are also scattered around, but someone has to Risk assess this and put it into some kind of formal document, which never ever happens.) I have now resorted to adding this caveat to the EIC Comments section when applicable.

The above scenario is quite common because the client often takes on a floor space populated with existing floor boxes

Something along the lines of: The Client has stated they will ensure that RCD protection is afforded to each desk with the use of an in line RCD between floor box and under desk sockets for example and these floor box desk supply sockets are not for general purpose use. Cleaners sockets that are RCD protected and readily accessible, shall only be used for general purpose use.

I'm not sure how legally exposed this leaves me or the legal implications of this sort advice so Id treat it with caution.
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Use of RCD protection in industrial and commercial installations

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