Consumer unit replacement

[Mikey10695]

Hi, we have been asked to relocate a consumer unit however the meter cupboard will be on an outside wall 7m away from the consumer unit, the main switch is under 80amp, im just wanting some opinions on the way to overcome this, am I right in thinking I could run 16mm swa from the consumer unit, cleated to an outside wall, running to an adaptable weatherproof box situated next to the meter cupboard, then using Henley connector blocks, i could connect the swa to the tails coming from the meter box.

 

[Mikey10695]

The meter boxes have knockouts in the bottom that can be reinstated later on..
I would come out of the bottom in trunking and then go bottom entry into an enclosure with the isolator inside.
We’re supposed to use designated entry points in the meter boxes

Ok thankyou for your help! Ill will get all the info needed tomorrow to be more certain and will post updates, i appreciate it

 

[Mikey10695]

Ok thankyou for your help! Ill will get all the info needed tomorrow to be more certain and will post updates, i appreciate it

Hi I know it isnt

Ok thankyou for your help! Ill will get all the info needed tomorrow to be more certain and will post updates, i appreciate it

the dno will be coming tomorrow but im not sure if they will use a 100amp with 25mm tails or an 80amp, its more likely going to be a 100amp switch but as the job is temporary and the house load will not even exceed 80 amps let alone 100amps do you think it would be fine to connect a 16mm cable from the meter to the vonsumer unit even if the dno use 25mm tails or shall I use a 25mm cable too

 

[Mikey10695]

Obviously once the job gets going in a few months i will upgrade the tails to 25mm once we move the consumer unit closer to the meter

 

[richy3333]

Jesus wept, I really dont think you should be doing this job

 

[davesparks]

That would make sense yes! Am I right in saying by using 16mm swa cable the fused isolator will be an 80amp fused switch?

No you are approaching this incorrectly, you don't pick a cable size then work backwards to the fuse size. You need to establish the design load and then work through the calculations to establish the correct fuse size then the cable size.

 

[davesparks]

as the job is temporary and the house load will not even exceed 80 amps let alone 100amps do you think it would be fine to connect a 16mm cable from the meter to the vonsumer unit even if the dno use 25mm tails or shall I use a 25mm cable too

Whether it is temporary or not it needs to be carried out in accordance with bs7671 including initial verification.
It won't be fine to connect a cable directly from the meter to the CU, if the length is 7 metres, regardless of what size it is.

 

[Deleted member 26818]

No you are approaching this incorrectly, you don't pick a cable size then work backwards to the fuse size. You need to establish the design load and then work through the calculations to establish the correct fuse size then the cable size.

I wish that still were the case.
Now we have to use 25mm2 tails irrespective of the load, just because there may be a 100A DNO fuse.
We also (since the 18th) will have to use 100A mains switches and RCDs if the manufacturers’ instructions tell us to.

 

[GeorgeCooke]

No. Manufacturers instructions are guidance only and don't have to be followed, especially if they are wrong (which is not uncommon).

 

[Deleted member 26818]

No. Manufacturers instructions are guidance only and don't have to be followed, especially if they are wrong (which is not uncommon).

Unfortunately where it comes to DBs, the 18th now requires us to comply with MIs.

 

[Dustydazzler]

If the MIs starts to place all mcbs upside down would we simply follow like sheep ?

 

[Charlie_]

Unfortunately where it comes to DBs, the 18th now requires us to comply with MIs.

Another reason not to use sy and only basec approved cables

 

[Deleted member 26818]

Another reason not to use sy and only basec approved cables

New testing and certification scheme launched for YY, SY, CY control… | BASEC

In response to direct demands from the marketplace, BASEC has launched a certification scheme to encourage standardised and consistent levels of quality for…

www.basec.org.uk

 

[Charlie_]

For those that have never read any