rcd regs

[norfolklec]

does anybody know the current regs regarding rcds on socket outlets when computer terminals are connected to the circuit? this installation is industrial and needs a certificate.what,if any ,upgrade is needed?

 

[Spudnik]

All socket outlets should now have RCD protection.

The circuit supplying the PC's should also have high integrity earthing if there are a number of them.

 

[norfolklec]

thanks jason thats what i thought but i suppose its better to check.circuit is fed from a3 phase mem board rcbos will have to be used. any probs with that?

 

[acat]

thanks jason thats what i thought but i suppose its better to check.circuit is fed from a3 phase mem board rcbos will have to be used. any probs with that?

They are better IMO


Chris

 

[norfolklec]

thanks acat thats just what i needed to know

 

[Lizard King]

Just to watch out for - RCDs/RCBOs tend to create 'nuisance' trips if used to supply more than a few workstations on one circuit. A single PC or monitor can be expected to produce up to between 1-2mA earth leakage in normal operation. It's best not to permit any more than 25% of the rated 30mA earth leakage to be present in normal conditions to avoid nuisance trips. Therefore a good rule of thumb is to limit the number of workstations served on a single 32A/30mA RCBO circuit to 8.

Also "All socket outlets should now have RCD protection" is a bit of a 'catch-all' statement and is not strictly accurate. Indeed, you do not need to use RCDs if the socket outlets in question are "for use under the supervision of skilled or instructed persons..." [Reg 411.3.3]

A definition of "instructed persons" is anyone who has been adequately advised by a skilled person to enable him/her to avoid dangers which electricity might pose. In commercial installations all employees should come under the Electricity at Work Regulations, which require a safe system of working thus there should be "skilled" staff in place to ensure all employees are "instructed". Given these requirements, there is no need to provide RCD protection to socket-outlet circuits intended for use solely by the staff or permanent occupants of the area in question.

My own take on this exception is that the new advice on RCDs in the 17th Ed was primarily aimed at the domestic environment and making sure all household circuits are safe. It was never the IEE's intention that a blanket strategy would be applied, with RCDs now used for each and every socket-outlet circuit, regardless of circumstance or environment....!

[I'm sure this has been debated many times on this forum before, but these are my thoughts in any case...]

LK

 

[Sintra]

Unless specifically labelled or suitably identified, all 13A socket outlets must be protected by a 30ma Rcd. 411.3.3

Although your cables must also be installed in a method that does not require RCD protection.

 

[caddy]

Unless specifically labelled or suitably identified, all 13A socket outlets must be protected by a 30ma Rcd. 411.3.3

Although your cables must also be installed in a method that does not require RCD protection.

I agree with Lizard King on this one, some socket circuits in commercial / industrial situations can be "exempt" RCD coverage. This also includes the installation method. Just becuase the cables may be in a wall if the installation is under suprervision of a "skiiled" or "instructed" person then RCD protection of buried cables may not be needed. For instance sockets intended for computers or permantly connected office equipment can be exempt however the socket allowed for the cleaner to use would be rcd protected.

We carry out works at various commercial / industrial sites that are under the supervision of a maintainance person / persons and as such are deemed to be skilled.

 

[pennywise]

They are deemed skilled until it goes ---- up

 

[Notsosmart]

IMHO herein lies the problem with the regs; they are too open to misinterpretation, reg 411.3.3 (i) does state that rcd's must be used for socket outlets under 20A but an exception is allowed if;
(a) sockets are under supervision or
(b) a specific labelled or identified socket outlet is used for a particular item of equipment (i.e. radial to a freezer)
Edit: Or as in your case P.C's ~ One way of ensuring that only computer equipment can be plugged into the ring/radial is to use Tbar sockets and plugs.

So as long as the enterprise has a competent person looking after it then no RCD required otherwise err on the side of caution.

 

[Des 56]

I agree entirely with Lizzard kings post

The Rcd everything on the planet was aimed at Diyers and domestic installs that were and are installed to pathetic standards
They made a mess of the requirements by trying to overcome this and then realised the implications for commerce and industry,thats when the skilled person get out claiuse had to be hastily incorporated into the regs
I think they will admit to the mess shortly and ammendments will likely seperate domestic and comm/ind installation requirements as far as rcds are concerned

 

[Notsosmart]

I agree entirely with Lizzard kings post**

The Rcd everything on the planet was aimed at Diyers and domestic installs that were and are installed to pathetic standards
They made a mess of the requirements by trying to overcome this and then realised the implications for commerce and industry,thats when the skilled person get out claiuse had to be hastily incorporated into the regs
I think they will admit to the mess shortly and ammendments will likely seperate domestic and comm/ind installation requirements as far as rcds are concerned

** As do I, unfortunatly we live in a health and safety/Litigation gone mad society where an individual will always look for someone to blame, so within the commercial/industrial environment it will be down to us as the skilled competent electrician to ensure that supervision exists. (I have considered getting a name from the cutomer to add to the certificate [and I'm not working for myself])

Derrier covering I'm afraid, is now the name of the game.

I also agree with you Des that as usual the regs get hurridly issued with all and sundries contributions muddying the water's until we as the poor saps have to question exactly why and wherefore (Ok I still haven't got over the 15th edition fiasco)

 

[bugsy]

Trading floors we work on will not permitt the installation of RCD / RCBO.s on trading floor terminals or servers, this is not in contravention of the regs