Remedial Action Report - electrical survey

[chrisdicko]

Im just going through some actions from when we got an electrical survey done by Connaught, but I'm not 100% on what to do on one of the final ones:

"Circuit doubled up - alternative arrangement advised."

This is a lighting circuit, which supplies a corridoor, 2 plant rooms, toilets, and 2 emergency light circuits.

There are approximately 7 wires going in to one MCB which obviously isn't best practise. These lights were done long before I started. 2 of the wires are for emergency light circuits, and I think the other 5 wires are for a circuit of lights in 5 rooms. (I think)
The easy solution would be to put each light circuit (if I'm correct above) on 5 separate MCBs, but what would the solution be for the emergency lights? As the emergency lights would need to come on if 1 (or any/all) of the 5 MCBs tripped/lost power.

Or being just an advisory can I legally leave it as is?

Here is said issue:

 

[sparkwright]

Before you started what?

The simple answer is the lighting should be arranged so;
If one area of lighting fails, then emergency lights in that same area should activate.

 

[EFLImpudence]

It is also on a 16A breaker.

There are a couple of unused breakers.
It could be easily put right.

 

[chrisdicko]

Long before I started working here.

I said above that the best solution would be to put the lights on their own circuit, which id like to, but the emergency lights are all connected (except for one light), which would mean re-wiring all the emergency lights which will be a massive job.

So I'd need for all the emergency lights to activate, if one MCB trips.

 

[Taylortwocities]

I can't tell from the pic what the CSA of all those wires in teh B16 breaker are but I'll bet they are only 1.00 or 1.5mm. So a 16amp breaker is too big for those cables. You woukld expect a 6amp or 10amp depending on conductor size.

You should split those circuits up onto several B6 breakers.

For the emergency lights it depends on what type you have. If they are non-maintained luminaires they must be activated by failure of supply
to the normal lighting. They must therefore be connected to the same lighting supply MCB as the local normal lighting final circuit.

 

[ricicle]

Your replies are unclear - are the local emergency lights connected to the relevant local lighting circuits ?

Or do you mean the em. lights are all connected to one circuit cable ?

If the latter then you may be able to change the lights to maintained ones which is a possible solution.

 

[chrisdicko]

Yeah, the MCB is too big and will get changed that's another advisory to do.

Apologise if I'm not explaining it too well. Yes the emergency lights appear to be on a circuit of their own, like a lighting circuit.

I've drawn a quick pic to try to illustrate it. I'm on my phone so hope u can see it ok.

 

[chrisdicko]

All the emergency lights are none maintained by the way

 

[chrisdicko]

There some form of emergency light relay you can buy? With various inputs, and if one fails, it switches to activate the e/m lights?

 

[ericmark]

Looking at picture I was assume the 16A MCB is feeding the lights. With florescent lighting maybe not a problem but if ceiling roses are used then likely there will be an overload with the ceiling roses which are normally rated at just 5A although no problem using a 6A MCB.

However splitting circuits can also be a problem with two way switching as in years gone by it was common to take just two core and earth between switches and borrow the live from another switch on same plate. Spiting the supplies can in this case cause a borrowed neutral which is dangerous.

Emergency lights should be supplied from same MCB as the main lighting for that area.

As a commercial electrician I was brought up with the idea of one terminal for each wire but with domestic that is not it seems the normal way with nearly every ring circuit having two wires to one MCB. The commercial boards I used would have DIN rail with linked terminal block and if the only problem is having so many wires into one MCB then that is an easy way out. I have also used it to fault find where a large fuse or MCB has been tripping I have fitted DIN rail flip out fuse carriers each with a small fuse. So there are many ways around the problem.

But "Circuit doubled up - alternative arrangement advised." is rather vague. It tells one nothing. My house has 9 ceiling roses which are daisy chained normal method however it could also be wired with 9 cables all returning to the consumer unit and of course the load would be the same. So the fact that there are 7 wires means nothing. What we need to know is what is the load and what type of equipment is feed from those 7 wires. So in short what you need is "an electrical survey" ups seems some one has not been doing their job? If I had been doing the same job in old days it would be marked "Further investigation required" as it does ring alarm bells. Likely I would have pointed it out during the survey and asked if you wanted me to do the further investigation. The fact that that code as been removed from the new forms does not really alter the fact that further investigation is required.

 

[ricicle]

I see no problem with leaving rooms 2-5 on their own circuit with the relevant em. lighting circuit.
Then maybe put rm 1 on it's own circuit with it's em. light.

There are no rules to say how many cables can leave an mcb. Bit poor if starting from a new job but if it's existing then where's the problem.

 

[ericmark]

Just seen your plan if they are florescent lamps which will have their own fuse inside the fitting then nothing really wrong with what you have. A better method of joining the cables is really all that is required.
I would consider the idea of a key switch for emergency lights which could also be used as a junction box reducing number of cables into one MCB.

 

[AndyPRK]

All Room 1 on a 6A
Other rooms on a 10A

 

[sparkwright]

All Room 1 on a 6A
Other rooms on a 10A

This is what I would consider doing too.

 

[Adam_151]

Also consider how the cable is installed, the rating of 1.5mm² twin and earth clipped direct away from other circuits and insulation is higher than you might imagine.