2-way CU meter tails

[AlexCarp]

The idea is to fit one of these 2-way CUs with an RCD. It is to supply all outside circuits, so a separate CU is the sensible way to go. A 16A mcb for a socket and another 6A mcb for outside security lighting. 6mm cable will easily do in supplying the 2-way CU. The idea is to keep it entirely separate from the main house electrics, apart from both coming through the same meter. As the idea is to keep both CUs separate, is inserting connector blocks in the meter tails to the main house CU and connecting 6mm cables from the blocks to the 2-way CU OK? This looks like the optimum solution and easier to do as well. Also the main CU look rather full.

Would others take the 2-way CU from the main house CU? Thanks for any comments. BTW, I will not be doing the work. I want the best way of doing it.

The meter tails will have a Henley junction block like this with the 6mm cable in the junction supplying the 2-way CU.

 

[Spark123]

Henleys in the meter tails, don't know if 6mm will be big enough for fault current. Your electrician should be able to advise.

 

[AndyPRK]

Or you could fit an rcbo in the existing cu if room.

Are you talking one light on a wall or underground cabling?

 

[AlexCarp]

Or you could fit an rcbo in the existing cu if room.

Are you talking one light on a wall or underground cabling?

The existing CU is rather full. Also the idea is to "separate" the outside circuits and the main house circuits. If there is a problem with outside circuits it will not affect the inside circuits. Outside is easily isolated as well. It all makes sense. As I stated the there will be a 6A mcb for outside lights, about 4 of them. There may be extensions in armoured cable in the futures. And a 16A mcb for an outside socket, which will go a short distance underground in armoured cable. The armoured cable will be run right back to the 2-way CU.

The meter tails will have a Henley block like this with 6mm cable in the junction going to the 2-way CU.

 

[AlexCarp]

...

 

[PrenticeBoyofDerry]

Does rather full mean full?
Depending on you board configuration, you could fit a MCB or RCBO to the existing board, take feed from that to a 2 way CU. If done correctly the only effect the Main CU will have on the 2 way CU, would be when the main isolator is opened.

And hope you are fully aware of the legal side of installing new circuits.

 

[AlexCarp]

Full means full. Difficult to get cables in. The issue as I see it, are the 6mm cables from the Henley blocks to the 2-way CU OK. They are clearly way big enough for the maximum load ever drawn on the 2-way CU. A 6A mcb and a 16A mcb will draw well under the 30 odd amps a 6mm cable can cope with.

 

[JohnD]

What made you decide to use 6mm cable? The supply to the Henley, and cables upstream of the MCBs in your CU, will be fused at about 100A.


This is a DIY install isn't it?

 

[PrenticeBoyofDerry]

Full means full.

Indeed it does, but what does rather full mean?

The issue as I see it, are the 6mm cables from the Henley blocks to the 2-way CU OK. They are clearly way big enough for the maximum load ever drawn on the 2-way CU. A 6A mcb and a 16A mcb will draw well under the 30 odd amps a 6mm cable can cope with.

The issue as I see it, is you are unsure what is the correct sizing of the cable to the mini CU, so I would assume this is not a task that you are over familiar with, so may I ask again, in another way? In what way are you going to make this a legal installation?

 

[AlexCarp]

PrenticeBoyofDerry and JohnD, please read the first post. I assume none of you know. Is that the case? If someone does will they please contribute.

 

[EFLImpudence]

And - What did you think when you read the first reply?

 

[JohnD]

I want the best way of doing it.




Last edited by AlexCarp on Sun Dec 15, 2013 4:35 pm, edited 1 time in total

In which case, the best way would be to get a competent electrician to design and install it.

 

[AlexCarp]

In which case, the best way would be to get a competent electrician to design and install it.

Competent electrician? That is not the case here, otherwise one would have said yes 6mm is fine or a min of this size or whatever. In short, you do not know otherwise you would have given the right or wrong way.

The Irish religious bigot need not reply. I find this man's handle offensive.

 

[PrenticeBoyofDerry]

PrenticeBoyofDerry and JohnD, please read the first post. I assume none of you know. Is that the case? If someone does will they please contribute.

Assume away my friend, I read your first post and have re-read it and cannot find any information there, that answered my question to you.

If the person you decide to employ to do this task, is indeed a competent electrician, they will once seeing your installation in it's full glory and the circuits you propose to add to this, be able to offer you informed advice on how this task is best completed.

 

[AlexCarp]

And - What did you think when you read the first reply?

He wrote that he didn't know. It least he was honest.