I'm a bit confused ...
Kind Regards, John.
Wouldn't the three RCBOs fit in the 3 spare spaces in the CU?
Kind Regards, John.
Many computers in office. How many circuit breakers?
- Thread starter ashirusnw
- Start date
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Oh poo 
Write out 100 lines
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
Write out 100 lines
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
I must read the responses before I go shouting my big mouth off
We're all guilty of that, one time or another!!Oh poo
When, many moons ago, I devised a method (involving pens and sellotape) to semi-automate the process of writing 100 lines, I ended up with a very sore backside - back in the days when punishment meant punishment
... and if, like you, I'd still only done 43, my backside would probably have been even more sore!Kind Regards, John.
I was just going overboard, John.
He said he needs 30 double sockets - 60 outlets - 21 of which will be computers........39 for god knows what.
Because he used the word 'overload', I've given him 32A per radial - 192A total - he's not overloading that.
As for saving of cable......you are assuming that you know the layout of the room and where the sockets are situated in relation to the CU.
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You've lost me there. In what sense have you "given him 32A per radial - 192A total" when those 6 radials are protected by 3 x 32A RCBOs? He would surely overload those circuits with >96A shared equally across the circuits in exactly the same way as he would with just one radial per RCBO? Also, as I said before, as far as earth leakage is concerned, that will be shared amoungst just 3 RCBOs, even though there are 6 radials, so the 'two radials per RCBO' does not help earth leaakage-wise. All-in-all, I still don't see what's gained by having two radials per RCBO.I was just going overboard, John. He said he needs 30 double sockets - 60 outlets - 21 of which will be computers........39 for god knows what. Because he used the word 'overload', I've given him 32A per radial - 192A total - he's not overloading that.
Indeed. I intended to write 'possibly save cable', but didn'tAs for saving of cable......you are assuming that you know the layout of the room and where the sockets are situated in relation to the CU.
Kind Regards, John.
You know what, John, I haven't even read your post before typing this reply
I've just been down for a coffee and on my way back upstairs it suddenly dawned on me what a ridiculous statement I'd made ha ha.
It's 32+ Amps for each cable - but obviously, he can't pull that - what a knob (me, I mean)
I've just been down for a coffee and on my way back upstairs it suddenly dawned on me what a ridiculous statement I'd made ha ha.
It's 32+ Amps for each cable - but obviously, he can't pull that - what a knob (me, I mean)
No problem - I was just getting a bit worried that maybe I was going a bit madYou know what, John, I haven't even read your post before typing this reply
Cheers, John.
Trying my best to follow this so far, given I'm not a sparky myself.
The consumer unit has a RCD in the last position. I take it from the advice so far that the RCD should be moved so it only protects the circuits that don't run computers (e.g. the air conditions, lighting circuit, kitchen mains sockets) and then have the Circuit Breakers that cover the circuits which computers are typically plugged into "outside" of the RCD or it will trip the whole time.
(And if I do this I have to warn all users that there may be earth leakage or something.)
I don't know what the bit about high integrity earthing means, I'm afraid. Tried to Google but couldn't get what in means in practice when we're running now cabling for these 3 new sockets.
Just to confuse you, it may turn out that I have another 1 or 2 places on the Consumer Unit as some of those CB are covering just a single double socket so I can extend those to an entire circuit.[/i]
The consumer unit has a RCD in the last position. I take it from the advice so far that the RCD should be moved so it only protects the circuits that don't run computers (e.g. the air conditions, lighting circuit, kitchen mains sockets) and then have the Circuit Breakers that cover the circuits which computers are typically plugged into "outside" of the RCD or it will trip the whole time.
(And if I do this I have to warn all users that there may be earth leakage or something.)
I don't know what the bit about high integrity earthing means, I'm afraid. Tried to Google but couldn't get what in means in practice when we're running now cabling for these 3 new sockets.
Just to confuse you, it may turn out that I have another 1 or 2 places on the Consumer Unit as some of those CB are covering just a single double socket so I can extend those to an entire circuit.[/i]
I gave you a link that tells all
You'll need to install ADDITIONAL earth cabling NOW to comply.
Your electrician must know about this, get another if he doesnt.
You'll need to install ADDITIONAL earth cabling NOW to comply.
Your electrician must know about this, get another if he doesnt.
After reading your other posts on this and other forums I have come to the conclusion that you don't have a competant electrician on site, and you are muddling through this yourself.
Please get a competant electrician to do the design and install!
Please get a competant electrician to do the design and install!
sorry but the link is too much electrical jargon - even for a guy with a degree in the engineering like me
do we need addtional earth cabling even if those sockets aren't covered by a RCD?
do we need additional earth circuit that connects all the double sockets or something?
sorry for all the questions - electrician is subcontracted and I have to communicate to him via contractor as he doesn't speak english so have to double check everything. (he may even me competant, but I don't know)
when it's all done, I've got a "proper" electrician to safety test it
In simple terms pc psu's leak, the leak might be 3-4 mA per unit, so the risk is that having a rcd with 30mA set could trip if you have 7 pr so units on the ring(s) under the same rcd.
Alternative could be an rcbo board, say 4mm radials 30 amp 30mA rcbo's with a strict limit of 5 pc's per radial. The issue being how to prevent more than 5 pc's being plugged in per installed radial.
A solution being to have all pc power leads adapted with twisted earth plugs and sockets, thus the restriction is designed in.
Alternative could be an rcbo board, say 4mm radials 30 amp 30mA rcbo's with a strict limit of 5 pc's per radial. The issue being how to prevent more than 5 pc's being plugged in per installed radial.
A solution being to have all pc power leads adapted with twisted earth plugs and sockets, thus the restriction is designed in.
I agree. That diagram is dreadful.
Also it is an old (16th edition) text. Now superceded by BS7671 (2008).
Section 543.7 refers.
An easier guide to all this is in Wiring MAtters
However, for normal folk Section 7.6 in the On Site Guide gives a better description.
ashirusnw - surely you/the electrician has a copy of the OSG?
You need to sort this out or there wil be real issues when a lot of stuff is switched on.
Also it is an old (16th edition) text. Now superceded by BS7671 (2008).
Section 543.7 refers.
An easier guide to all this is in Wiring MAtters
However, for normal folk Section 7.6 in the On Site Guide gives a better description.
ashirusnw - surely you/the electrician has a copy of the OSG?
You need to sort this out or there wil be real issues when a lot of stuff is switched on.
Option 6
It may not comply with regulations but supplying banks of equipment using a centre tapped 230 volt secondary, centre tap to true ground, reduces the un-balance of earth leakage currents created by the filters. It does introduce a potential but managable hazard that the "neutral" is no longer close to earth potential and this may prevent this method being used on systems installed under BS7671 accreditation.
For some high reliability installations, ( such as un-attended hill top radio stations ) the use of an isolation transformer with it's centre tap grounded and connected the CPC of sockets is considered the only option for some equipment.
is the best way to supply equipment that will have large live to earth leakage currents when supplied direct from a mains supply.
It may not comply with regulations but supplying banks of equipment using a centre tapped 230 volt secondary, centre tap to true ground, reduces the un-balance of earth leakage currents created by the filters. It does introduce a potential but managable hazard that the "neutral" is no longer close to earth potential and this may prevent this method being used on systems installed under BS7671 accreditation.
For some high reliability installations, ( such as un-attended hill top radio stations ) the use of an isolation transformer with it's centre tap grounded and connected the CPC of sockets is considered the only option for some equipment.
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