Help - New Extension 2nd consumer Unit

[TiSwAs]

Hi, i know i'm going to need a qualified sparky for this one but i just want to get a 1st opinion before i get someone in.

We are having a side extension built and the current consumer unit is full and located in our porch. I personally think that the 2nd consumer unit should be located in the new extension.
The extension will be hard to wire due to it's location if a 2nd unit was located next to the exsisting.

See idea

This is my incoming and basically the consumer unit is located about 70cm above the meter inside the porch.

Questions -
i) how would the incoming be split to feed the exsisting and the 2nd units?

ii) is it ok to located the 2nd consumer unit in the loft space?

iii) when the incoming has been split can I run 25mm armored cabling partially underground then feed up through the cavity and then along the truss line to the new unit located in the loft space? (see green line on plans)?

If i'm barking up the wrong tree can someone explain the best thing to do?

Cheers
Dave

 

[bernardgreen]

Consumer unit in the loft space will mean climbing the loft ladder to reset a tripped MCB. Is that a good idea if it is the lights that have tripped out ?

Best advice is replace the existing CU with a larger one.

What are the white PVC and the low voltage cables going through the meter box ?

 

[ricicle]

Is it not feasable to replace the existing CU for a larger one?

 

[TiSwAs]

Consumer unit in the loft space will mean climbing the loft ladder to reset a tripped MCB. Is that a good idea if it is the lights that have tripped out ?

Best advice is replace the existing CU with a larger one.

What are the white PVC and the low voltage cables going through the meter box ?

Not bothered about climbing into the loft space - a 2nd consumer unit in the new extension showing would look unsightly

The cable running though the meter box is the power supply for the garage, the cable is sheilded by a scaffolding pole running under my garden!

Is it not feasable to replace the existing CU for a larger one?

From what i can tell, probably not, can't see how socket and lighting cables can be fed into the new part of the extension without lots of replastering.... unless i'm missing summat.

 

[Adam_151]

1) What is the proposed load in the new extension, what will the room be used for?

2) I don't like the Idea of a CU in the loft

3) I don't like the look/sound of that garage submain....

 

[securespark]

I wish I had a camera with me a few months ago.

I was doing a safety inspection on a house in Staffordshire. I asked the lady where the CU was.

"In the downstairs loo"

So in I went, and came out again. "Where?"

"Oh, you need a ladder..."

So I poked my head round the door and looked up. Nothing.

I found it eventually.

You have to climb a ladder, which you can't erect properly because the pan does not allow it.

You then have to lift a loft hatch, and the consumer unit is there, mounted in the horizontal plane just underneath the trap for the bath.

It was a conservative 9m away from the cutout, wired in tails (too long!)

The position of the unit meant that any heat generated by the RCD could not escape, meaning it was at risk of failing to trip.

It was at risk of being leaked on by the trap.

It was too inaccessible in an emergency.

Just to confirm my suspicions, I rang the area manager who agreed wholeheartedly that it was just about the most "AT RISK" CU installation he had ever known of.

DON'T PUT IT IN THE LOFT!!!!

Put it in the extension, sure, but make it accessible.

Even better, replace the existing one with a bigger board that complies, then you won't need anything in the extension.

Bernard - I think the SELV cable feeds the water meter unit or similar in the cabinet???

 

[TiSwAs]

1) What is the proposed load in the new extension, what will the room be used for?

Proposed load is home cinema equipment in one half - Plasma/projector/vcr/dvd etc - 2 x media servers and 2 PC's + lighting
2nd half of the extension will be a new ring main for the kitchen inc elec cooker and lighting

2) I don't like the Idea of a CU in the loft

Why not - whats wrong with that?

3) I don't like the look/sound of that garage submain....

Why whats wrong with that?

Can you expand and suggest rather than say that u don't like it....

Cheers

 

[securespark]

Why not - whats wrong with that?

See my above post!

It is an unprofessional and frankly dangerous design.

Not bothered about climbing into the loft space - a 2nd consumer unit in the new extension showing would look unsightly.

So are switches and sockets: are you going to put them in the loft?

No. Because it is inconvenient to access them and could be dangerous if an emergency arose.

As for your garage install, I can't comment fully as I don't know the full details, but unless the T & E is fully protected along its entire length underground (and with scaffold pole that is unlikely), it is not ideal.

Is the garage RCD protected?

 

[TiSwAs]

I wish I had a camera with me a few months ago.

I was doing a safety inspection on a house in Staffordshire. I asked the lady where the CU was.

"In the downstairs loo"

So in I went, and came out again. "Where?"

"Oh, you need a ladder..."

So I poked my head round the door and looked up. Nothing.

I found it eventually.

You have to climb a ladder, which you can't erect properly because the pan does not allow it.

You then have to lift a loft hatch, and the consumer unit is there, mounted in the horizontal plane just underneath the trap for the bath.

It was a conservative 9m away from the cutout, wired in tails (too long!)

The position of the unit meant that any heat generated by the RCD could not escape, meaning it was at risk of failing to trip.

It was at risk of being leaked on by the trap.

It was too inaccessible in an emergency.

Just to confirm my suspicions, I rang the area manager who agreed wholeheartedly that it was just about the most "AT RISK" CU installation he had ever known of.

DON'T PUT IT IN THE LOFT!!!!

Put it in the extension, sure, but make it accessible.

Even better, replace the existing one with a bigger board that complies, then you won't need anything in the extension.

Bernard - I think the SELV cable feeds the water meter unit or similar in the cabinet???

I can understand what you are saying about inaccessability problem and the heat problem for the loft space etc... it''s just that i can't see how the new cables would be fed to the extension without a shed load of distruption in other rooms that have just been decorated etc....

correct about the low voltage cable is for the water meter.

 

[TiSwAs]

Why not - whats wrong with that?

See my above post!

It is an unprofessional and frankly dangerous design.

As for your garage install, I can't comment fully as I don't know the full details, but unless the T & E is fully protected along its entire length underground (and with scaffold pole that is unlikely), it is not ideal.

Is the garage RCD protected?

The cable is fully protected by a scaffold pole for it's entire length under ground and protected by an RCD- yes not ideal but i will be ripping up the front lawn when the building work commences so i will run armored around the garden - unforutnatly i have a father who thinks he knows what he was doing and he did it for me as a favor when we first moved in 9 years ago.

 

[securespark]

How were you going to run the submain?

Run the extension circuit cables in the same route.

 

[TiSwAs]

How were you going to run the submain?

Run the extension circuit cables in the same route.

I'm not a sparky and i don't know much about electrics or regulations or what items are on sale to do this but the idea was that i thought of tapping off the main incoming with a Y connector out of the meter with 1 x 25mm to the exsisting CU and 1 x 25mm to the new one in the extension).
i thought of running the cable out of the mains box and into the ground and up though the cavity into the loft space and then mount the CU next to the loft access hole in the ceiling.
I thought 1 25mm armored cable would be much easier to run than say 5 others or what ever cables it takes to run for my project.

Cheers

 

[RF Lighting]

An accesible consumer unit does not have to be an eyesore. You could build it into a cupboard, or use something like a flush mounted CU.

Also it makes installation and maintanence a real pig, plus if something goes wrong you may need to switch the power off in an emergency, or even if something goes wrong with the CU, such as it catching fire (unlikely I know, but it does happen) you will never know if it is in your loft.

Hager CU

 

[RF Lighting]

How were you going to run the submain?

Run the extension circuit cables in the same route.

I'm not a sparky and i don't know much about electrics or regulations or what items are on sale to do this but the idea was that i thought of tapping off the main incoming with a Y connector out of the meter with 1 x 25mm to the exsisting CU and 1 x 25mm to the new one in the extension).
i thought of running the cable out of the mains box and into the ground and up though the cavity into the loft space and then mount the CU next to the loft access hole in the ceiling.
I thought 1 25mm armored cable would be much easier to run than say 5 others or what ever cables it takes to run for my project.

Cheers

You would need to protect your new submain with a fuse at the supply end. You are not allowed to connect a submain directly to the incommer.

Some DNOs will not allow you to fit your equipment in their meter cabinet.

 

[TiSwAs]

How were you going to run the submain?

Run the extension circuit cables in the same route.

I'm not a sparky and i don't know much about electrics or regulations or what items are on sale to do this but the idea was that i thought of tapping off the main incoming with a Y connector out of the meter with 1 x 25mm to the exsisting CU and 1 x 25mm to the new one in the extension).
i thought of running the cable out of the mains box and into the ground and up though the cavity into the loft space and then mount the CU next to the loft access hole in the ceiling.
I thought 1 25mm armored cable would be much easier to run than say 5 others or what ever cables it takes to run for my project.

Cheers

You would need to protect your new submain with a fuse at the supply end. You are not allowed to connect a submain directly to the incommer.

Some DNOs will not allow you to fit your equipment in their meter cabinet.

Ok thanks,
so ideally then -
Expand exsisitng CU with a bigger one....

QUESTION - Can I by laws/regulations running T&E cables into the ground and run T&E cables inside a cavity walls???