circuits in an mcb

[ringpuller]

Hi anyone got a theory on the following,the property is a high storey flat one lighting circuit only.
one mcb three phase conductors in the mcb(not three phase) one neutral and earth for a lighting circuit. The neutral and earth in the lighting circuit go to every point but the live conductors are fed at different stages from the con unit.
How would you code this on a PIR code 2? and how could if any remedy it for an install cert

 

[WayneL]

Why do you want to code it? What's wrong with it?

 

[Des 56]

If I understand the question

Using a what if situation
What if someone splits those lives,then there would be shared neutrals and cpcs.
however, that is not what exists,so the pir must reflect whats found

Why do you believe it needs coding ?

 

[Rikki Barrett]

This is a good one.
So IF there is borrowed neutrals etc, it is acceptable to have more than one circuit put into an MCB? Obviously suitable labelling in place etc.
So what are peoples thoughts on having more than one circuit put into an MCB with NO borrowed anything? Is this acceptable? I mean my first thoughts would be "what about discrimination for one""but it has warning labels" blah blah blah. I have seen alot of this but not too sure about how this would look to other electricians. I dont like it myself.

 

[ringpuller]

To clarify there is one lighting circuit,fed to different points three times from one mcb the circuit has only one neutral and earth to each lighting point.It is wired in steel conduit embedded in the construction of the flat circa 1970.
What i'm asking is would you code it as a code two according to the niceic code two shared or borowed neutrals.Next question how would you overcome the problem without a rful or partial rewire of the lighting circuit

 

[Risteard]

But there isn't a borrowed neutral.

 

[ringpuller]

Would you then say potetially that you ould overload that cable via seperate loads on the three lives as opposed to one neutral and one earth in load or fault condition

 

[Risteard]

Not sure why they've only used one neutral. It would be OK if it had been a three-phase lighting circuit.

As for overloading neutral I suppose you would need to calculate that.

 

[WayneL]

This is a good one.
So IF there is borrowed neutrals etc, it is acceptable to have more than one circuit put into an MCB? Obviously suitable labelling in place etc.
So what are peoples thoughts on having more than one circuit put into an MCB with NO borrowed anything? Is this acceptable? I mean my first thoughts would be "what about discrimination for one""but it has warning labels" blah blah blah. I have seen alot of this but not too sure about how this would look to other electricians. I dont like it myself.

But it's not more than one circuit - it's one lighting circuit

Think of running a feed to a ceiling rose.

Then running your feed to a second ceiling rose.

Does it matter if the feed for the second ceiling rose is run from the start of the first cable-run (the MCB) or the end of it (the first ceiling rose)?

 

[ringpuller]

So the general consensus is you wouldnt code it on a PIR as a code 2, if other work was carried out to warrant a install cert would you make a comment

 

[WayneL]

So the general consensus is you wouldnt code it on a PIR as a code 2, if other work was carried out to warrant a install cert would you make a comment

Don't see why - in my opinion there's nothing wrong with it - it's just a different installation method.

 

[Deleted member 9648]

As Wayne states...it's one circuit,as long as the conductors are appropriate to the rating of the MCB what is the problem.....Perhaps ringpuller you could explain why you feel it warrants a code?

 

[nickblake]

there is not a problem doing this as long and has already been stated is that the current of the protective device and the cabling is of correct current carrying capacity