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Fin170
Sorry bud didn't mean you personally, in relation to earlier discussion in the thread :wink5:
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Sorry bud didn't mean you personally, in relation to earlier discussion in the thread :wink5:
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SYKRAPS
No poblemo
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MarkieSparkie
Read my post #102 mate, the doom mongers are always predicting it's imminent demise, purely conjecture rather than evidence based fact.
The last hiatus over it's demise, it was speculated that the UK representatives on CENELEC were prepared to trade the RFC for agreement on harmonised cable colours, in reality nothing was traded and the UK proposal for cable colours was adopted by all member countries without a whimper. Later it emerged from the minutes of the UK proposal strategy meeting that they had a number of other items which they might have traded if pushed, but the RFC was definitely not part of that UK agenda.
It seems that the other member countries of CENELEC are not really interested or that bothered about the UKs RFC or the BS1363 fused plug. Therefore as long as UK doesn't try to coerce them into adopting the RFC and/or the fused plug, it's not in anyone's interest to rock the CENELEC boat, because it turns out that most of them also have country specific exceptions which they wish to preserve.
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Engineer54
Funny how it always seems, that it's the lectures and tutors that are the doom mongers on ring circuits... Perhaps it's because they aren't up to the job of explaining the structure and make-up, or the process of fault finding on ring circuits??
Going by some of the daft and also incorrect statements that have been given to students by their lecturers and tutors, ...and then conveyed here on the forum, i'm beginning to think that may not be too far from the truth these day's....
Going by some of the daft and also incorrect statements that have been given to students by their lecturers and tutors, ...and then conveyed here on the forum, i'm beginning to think that may not be too far from the truth these day's....
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MDJ
Thats the worse statment I have ever read, anyone who knows about electrical Installation practice would know that several power circuits is more practicable than a single ring, I'm not against rings by the way, I would always have at least 3 in a house, however, for starters you could have several 20 amp 30 MA RCBOs protecting several circuits and the nusience tripping would be a hell of a lot less than on a ring, and also 2-3 sockets max on a radial would illiminate overloading due to the lack of outlets on the circuit, I would suggest 4mm2 radials on 20 amp circuits myself and radials for fridges and freezers seperate again, a ring with a heavy load isn't balanced, it can be overloaded and due to collective earth faults very annoying for the house holder due to nusience tripping, but with several circuits if RCBOs are used the chances of collective earth faults very unlikey and nusience tripping the same.
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Fin170
Several 20a RCBOs using 4mm?
Don't suppose you could share some of your millionaire customers with me could you? :lol:
Don't suppose you could share some of your millionaire customers with me could you? :lol:
imago
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Again the will/stupidy/lack of knowledge of the end user is overlooked. You can't limit the load on a circuit by limiting the number of outlets on it. Anywhere it's deemed necessary will have a double adapter with a couple of six point extension leads plugged into it. Or one long extension lead to an arc welder, or some similar nonsense.
The arguement for several circuits with RCBOs applies equally to a well designed ring arrangement using RCBOs.
Which brings us back to either ring or radial is acceptable and page one of the thread.
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MDJ
I see your first point but will never agree 1 ring is equal to several radials, just impossible IMO, it just doesn't make sence to me and never will.
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MDJ
ok fair enough.
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Silly Sausage
This linear thread is going round in circles... :joker:
imago
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Adam W
Ah well now you're talking about 'nuisance tripping' in which case I would agree. You didn't mention that in the previous post; I was talking about overloading - a customer could happily draw 30A from upstairs or downstairs continuously from any room, while they couldn't with a 20A circuit unless you have one radial per double socket, which seems like a waste of copper and CU space (not to mention money), and unnecessary considering BS1363 plugs contain a maximum 13A fuse.
Here is a question for you..
For arguments sake... Consider a standard ring circuit (32a Mcb 2.5mm conductor) It has an additional socket spurred off of one point.
Now imagine the extra spurred socket is wired away from the board, so there are 3 conductors in the Mcb, still conforms to the regs.
So therefore the cable that feeds that spurred socket is protected by a 32a Mcb and it is allowed.
Now disconnect the ring cables.
Suddenly that spur doesn't comply anymore...
Does anyone else find that a little strange?
For arguments sake... Consider a standard ring circuit (32a Mcb 2.5mm conductor) It has an additional socket spurred off of one point.
Now imagine the extra spurred socket is wired away from the board, so there are 3 conductors in the Mcb, still conforms to the regs.
So therefore the cable that feeds that spurred socket is protected by a 32a Mcb and it is allowed.
Now disconnect the ring cables.
Suddenly that spur doesn't comply anymore...
Does anyone else find that a little strange?
Or to put another way..
A 2.5 radial feeding 1 socket is fed off a 32a Mcb.
"not protected!"
But if you don't have an appropriate Mcb on the van, it doesn't matter, we'll just run in a couple of new legs to a new socket and bobs your uncle it's all tickety boo now because we've changed it to a spur off of a ring and that's fine!
A 2.5 radial feeding 1 socket is fed off a 32a Mcb.
"not protected!"
But if you don't have an appropriate Mcb on the van, it doesn't matter, we'll just run in a couple of new legs to a new socket and bobs your uncle it's all tickety boo now because we've changed it to a spur off of a ring and that's fine!
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Adam W
The maximum you can draw off it continuously is 26A though.
Use your second example of running in an extra leg and you're effectively increasing the CSA - ie you may as well be replacing it for 4mm.
No in the 2nd example what I meant was:
Putting into the Mcb, 2 more legs which go to another socket. So that you'd have the original socket fed by one 2.5 and the new one fed by two 2.5s
How does putting the new cables and socket in, increase the safety of the original circuit?
Putting into the Mcb, 2 more legs which go to another socket. So that you'd have the original socket fed by one 2.5 and the new one fed by two 2.5s
How does putting the new cables and socket in, increase the safety of the original circuit?
that is a very long winded way to fix a problem that doesn't exist!
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sedgy34
That'd make it a ring then?
Only until it stops lol:wink5: then it's a radial
A 32A MCB is overrated for a radial circuit run in 2.5 but it is not incorrect for one double (or single) socket outlet on 2.5.
Because the nature of the load is such that you cannot have an overload as the socket outlets will use fused plugs that limit the maximum current.
So where there is a situation where there cannot be an overload there is no requirement to provide overload protection, only fault protection and the MCB will provide fault protection.
In your example having a single spur off the MCB for a ring and then removing the ring would be still compliant with the regulations, however you would not be able to add outlets to this (now) radial.
max load is 26A, cable can handle 27A, so theres no problem. it's the same as any spur off the ring
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dpiers1980
are you not doubling your csa with a ring making the load you can draw off it higher hence 32a mcb does this not make the ring better for handling more load being drawn off any socket on it ?
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bigbaddave
Boy i think your right on the "Changing the subject slightly" certainly not on a ring main..
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Guest55
ring or 32a radial to grid box then 2.5 t&e branches to each appliance.
would be one way.
Just bumping some threads in the Electrical Wiring Theories and Regulations forum category here on our Electricians Forums. If this specific topic isn't current, just ignore it, it'll drop off the list in no time. However, if it's something you'd like to contribute to, feel free to reply and bring it back into current discussion.
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