RCD or Not

[simonspark]

Evening All,
Could one of you fine tradesmen, there's got to be one out there, help me out a bit here. I have been asked to install a ring circuit that is going to supply 17 computers in a school. I know that its going to be an IT install (separate earth terminals and all that) but what about the RCD situation? The regs state that the sockets should be protected by an RCD. But the natural leakage could well trip an RCD. I could split the circuit into two or more rings, but the logistics of doing such a thing are staggering. Trust me! Can I just put labels on each socket stating that they are for IT equipment only? And all wiring is going to be surface (nice!)
I am going to have to thankyou in advance, because the last time I tried such an action I failed.
Thanks

 

[simonspark]

If it is acceptable to mark up a non RCD protected socket with a label stating fridge/freezer only (taking into account of no flush wiring) why is it not the same for IT equipment.

 

[IQ Electrical]

The first thing you need to do is check with the Local Authority (assuming the installation is under their control) to see if there is a published specification covering this issue.

The last school installation that we did had a 'mini spec' stipulating RCD protection, high integrity earthing and a maximum of 6 'terminals' per ring final circuit.

 

[ezzzekiel]

. And no, I'm not competent

So is this theory or are you actually planning on doing the work after making the above statement?

 

[simonspark]

It's a private adult education school for language

 

[simonspark]

The statement was taking the p'''

 

[plugsandsparks]

Listen to IQ. Even if this establishment is not directly under authroity control this establishment may be using other internal guidelines which i would jump on the back off. End of the day, it costs what it costs. RCDs are here to stay so may as well get used to them.

 

[mogga]

Sounds like you NEED to get someone who knows what they are doing to plan and execute the job as you yourself admit not being competant nor qualified 94.4% means NOT Qualified doesnt it ?

 

[electromonkey]

Surface mounted install you say?

Unless it's on a TT then an RCD isn't necessary, would that be right folks?

 

[D80]

For socket outlets not in use by skilled or supervised persons RCD protection is needed.

 

[electromonkey]

I'm assuming metal conduit here as the OP says it's surface mounted?

What say you Steve?

 

[simonspark]

Sounds like you NEED to get someone who knows what they are doing to plan and execute the job as you yourself admit not being competant nor qualified 94.4% means NOT Qualified doesnt it ?

99.4%. Did I put .6?

 

[simonspark]

All surface mounted via trunking. No concealed wiring. And despite some of the slurs, I do know what I am talking about. And I think RCD's are fantastic. But...... I am sure that if equipment that can be sensitive to the protection that an RCD provides, as long as it is clearly labelled to state this fact,and it is not supplied via a TT sysyem, then it does not contravene the regs.

 

[simonspark]

Oh yeah. And also that there is provision elsewhere for RCD protected outlets.
I will have a chat with the NIC tomorrow. See what they say. If it's ok with them, then it's ok with me

 

[Welchyboy]

All surface mounted via trunking. No concealed wiring. And despite some of the slurs, I do know what I am talking about. And I think RCD's are fantastic. But...... I am sure that if equipment that can be sensitive to the protection that an RCD provides, as long as it is clearly labelled to state this fact,and it is not supplied via a TT sysyem, then it does not contravene the regs.

if your goin to omit RCD protection you will need it in writing from the client saying they are adequately supervised, to cover ur ---, or if any thing happens it will be ur word against theirs and you will likely cop it
think about these sort of things before you think about the cost of the job

also why are people even talking about ring circuits and 4mm cables???? WTF!!

surely earth leakage is your limiting factor in this equation so why not 16a/2.5mm RCBO radials with a 4 mm earth run back on each circuit to provide your high integrity earthing, supplying no more than 4 PC units per circuit, job done!

i seriously wouldnt chance loading an rcd up with any more likely load than 15mA as most i have ramp tested in the past will trip at around 20-25mA

 

[simonspark]

Final word. Mogga, you have made me smile. Calm down young man!!