Small Job in a school ?

[TPES]

I went to a school today to estimate a job.

Its only a small job, Couple of power points and data, Ive checked the CU and previous test certificates, (RFC, C32 MCB, 16 points, 2.5 T&E).

The sockets will be running IT equipment, But still i didnt notice and RCD, it could have been RCBO, either way my addition to this RFC will have to require and RCD to protect, right? as cables burried less than 50mm deep

It did state max ZS for this RFC on previous cert as 1667, So there must be an RCD in place, right?

Once complete i will issue a MWC correct?

I have mainly been working on domestic property, so when it comes to Industrial/commercial i get thrown out abit to what the requirements are... But regs are regs right? where ever the install is

 

[Spudnik]

I.. But regs are regs right? where ever the install is

100% correct so carry on as if domestic in this scenario.

 

[Johno]

you may need more liability insurance to work in a school

 

[stevey1983]

dont forget that IT equipment has earth leakage so you will need to know what this value will be, greater than 10mA will require high integrity protective conductor connections. Take a look in the onsite guide on pages 66, 67 and 68. Also you will need to split the circuit up accordingly or your RCD/RCBO will keep tripping, depending on the make, most of the ones i have tested lately seem to trip about 23mA even though their meant to be 30mA

 

[Sintra]

A 30mA RCD can trip at any current greater than 15mA and less than or equal to 30mA.

 

[cornburn]

Modern IT equipment has tiny earth leakage currents if any at all and two machines couldn't cause enough leakage to trip an RCD. We put 15 modern machines on 2.5 rings (high integrity earthed) all the time, with 2 rings sharing the same RCD, so 30 machines on one RCD. We've never had any problems as the leakage and power was calculated and the modern stuff is so efficient it's not an issue.

Also you could leave the circuit without an RCD if it's under the supervision of a skilled person (caretaker) but if the board will take one then of course you might as well fit an RCBO

 

[controlman]

Johno
You are right re the insurance
I needed 5m Public and CHAS certified to do works in any council building

 

[Mr Mark Sparks]

Modern IT equipment has tiny earth leakage currents if any at all and two machines couldn't cause enough leakage to trip an RCD. We put 15 modern machines on 2.5 rings (high integrity earthed) all the time, with 2 rings sharing the same RCD, so 30 machines on one RCD. We've never had any problems as the leakage and power was calculated and the modern stuff is so efficient it's not an issue.

Also you could leave the circuit without an RCD if it's under the supervision of a skilled person (caretaker) but if the board will take one then of course you might as well fit an RCBO

another grey area i dont class a caretaker as a skilled person(even if like most of them he" used to be a sparks")

 

[cornburn]

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another grey area i dont class a caretaker as a skilled person(even if like most of them he" used to be a sparks")

Yes it varies from site to site, some are muppets and some have had plenty of experience. At the end of the day with the 50mm in walls you're only really checking that no one screws into the cables, so if they have half a brain they should know not to do that! Most of the old schools round here are all in steel conduit too. Obviously get on an RCD if you can but if you need to add a socket for them it's a good get out if putting an RCD in means a new board install.