Electrical Regs nos required

[RoytheRoach]

I recentley did a T&I on a commercial site, I noted that there were 3 lighting circuit cables connected to 1no MCB and there should only be 1 circuit connected to 1 MCB. Also in the office area on the dado trunking there are 2 sockets next to each other but served from different phases potential 400V serving appliances. The installer has said the above is ok but I disagree. Are there any BS7671 reg numbers or any NICEIC info to prove the above are incorrect or am I wrong.

 

[johnboy6083]

the 3 cables in an MCB might be a ring with a spur from the MCB. that is perfectly fine. as for the sockets, i personally would try and stick with a phase per room, maybe a different phase on the lights. cant supply reg no's mate, but someone will be along who can, im sure

 

[RWJ]

Think the socket outlets are fine as long as they have the
View attachment 5289
label as per 514.10.1 reg Nominal voltage exceeding 230v between simultaneously accessible equipment.

 

[Engineer54]

I recentley did a T&I on a commercial site, I noted that there were 3 lighting circuit cables connected to 1no MCB and there should only be 1 circuit connected to 1 MCB. Also in the office area on the dado trunking there are 2 sockets next to each other but served from different phases potential 400V serving appliances. The installer has said the above is ok but I disagree. Are there any BS7671 reg numbers or any NICEIC info to prove the above are incorrect or am I wrong.

Not particually good practice, but nothing electrically wrong with more than one lighting circuit being protected by a single MCB... So long as all the normal parameters are OK.... As stated, the sockets just need to be labelled to conform.

 

[Des 56]

This question of 1 only conductor in an mcb as come up frequently and I have said my opinion on it in the past,but once again

I dont consider it bad practice,in fact as far as lighting circuits go,it can be beneficial,both as far as lower Zs for the branches and sensible cable routing
The example I use,is an installation where the layout requires lighting cable to be feeding a fitting and the second fitting requires the routing to run back via the mains position using that same route to the next fitting

Is it being suggested that to adhere to some folk law tale, that 2 or more conductors shouldn't be in an mcb, that extending circuits, because of that perception, to much greater length than otherwise could have be installed.makes it somehow a more compliant

As far as my opinion goes,the multiple conductors in the one mcb is "no problem at all",and in fact could be an indication of sensible routing

 

[SirKit Breaker]

I think the one issue that throws this up frequently is more in the domestic set up. Splitting circuits up on 17th edition CU's and putting lighting into 2 or 3 breakers to comply with "Segregation of circuits to minimise blah blah"

Cheers...........Howard

 

[IQ Electrical]

I recentley did a T&I on a commercial site, I noted that there were 3 lighting circuit cables connected to 1no MCB and there should only be 1 circuit connected to 1 MCB. Also in the office area on the dado trunking there are 2 sockets next to each other but served from different phases potential 400V serving appliances. The installer has said the above is ok but I disagree. Are there any BS7671 reg numbers or any NICEIC info to prove the above are incorrect or am I wrong.

1 Circuit per MCB yes but check the BS7671:2008 definition of a circuit.

Often self-contained emergency lighting is taken from the primary lighting protective device, through a test switch and on to the luminaires.

As for the sockets, can you imagine the chances (on a risk assessment basis) of circumstances arising that would create this great danger from adjacent outlets on different phases?

I noticed that in the final version of Amendment 1, the wording of 514.10.1 had been changed to 'where the nominal voltage exceeds 230V to earth.'
So there will no longer be a requirement to label in these circumstances although of course you still have the option!

 

[JUD]

This question of 1 only conductor in an mcb as come up frequently and I have said my opinion on it in the past,but once again

I dont consider it bad practice,in fact as far as lighting circuits go,it can be beneficial,both as far as lower Zs for the branches and sensible cable routing
The example I use,is an installation where the layout requires lighting cable to be feeding a fitting and the second fitting requires the routing to run back via the mains position using that same route to the next fitting

Is it being suggested that to adhere to some folk law tale, that 2 or more conductors shouldn't be in an mcb, that extending circuits, because of that perception, to much greater length than otherwise could have be installed.makes it somehow a more compliant

As far as my opinion goes,the multiple conductors in the one mcb is "no problem at all",and in fact could be an indication of sensible routing

I agree with Des. See reg 433.4 (parallel conductors).

As SirKit said you may not comply with "Segregation" unless all 3 conductors are feeding the same circuit.

I think the one issue that throws this up frequently is more in the domestic set up. Splitting circuits up on 17th edition CU's and putting lighting into 2 or 3 breakers to comply with "Segregation of circuits to minimise blah blah"

Cheers...........Howard

 

[malcolmsanford]

This anomoly is a throw back to the days when an installation would be supplied by a 4 way BS 3036 board where you had 1 lighting circuit, 1 ring final circuit an immersion and perhaps a cooker circuit.

As installations grew it was not like today, a DIY'er and even some sparks, instead of upgrading the board would "double up" on a fuse carrier and so you could have all sorts of scenarios.

Yes I'm afraid I'm still in the don't like more than one cable coming out of a way, it still to me looks odd, but as Des as said as long as it is of the same circuit, IE downstairs lights, then there is nothing in the regulations to prohibit it.