Alterations to properties with 16th Edition set-ups

[The General]

Evening all. Just getting my fireproof trousers on ready for being shot down in flames......I try not to post too many questions on here as it highlights how little I know, but I'm doing my best to learn from others and my own mistakes and sometimes there's no-one else to ask. So here goes:

I've been out to a house today which is going to be rented out - they wanted an additional socket put in before tenants move in. PME supply with 16mm tails, 10mm earth and a 16th Edition board with BS3781 MCBs and no RCD.

My question is around what are 'Requirements' and what are merely 'nice to do' actions in terms of work.

From conversations I've had with more experienced electricians, I've been led to believe that by making an addition to the circuit (i.e. spur for the extra socket) I would need to ensure that the installation is brought up to current standards.

So, in this case:
Upgrade 16mm to 25mm tails?
Upgrade 10mm to 16mm earth?
Install either an RCD upfront, an RCBO in that particular circuit, replace the whole board or use an RCD socket outlet?
Oh, and the tails were a lot longer than 3m, so a switchfuse at the cut-out too?

Obviously, this is significantly more work than the customer was expecting!!

Am I way off the mark here, or are all these actions necessary before I can put an extra socket in?!?

Thanks for your time (and patience)

 

[telectrix]

EXCEPT PME supplies

quote me the reg. for that.

 

[spark 68]

quote me the reg. for that.

542.3.1 which in turn points to 544.1.1

Now although 5441.1.1 refers to bonding conductors, 542.3.1 also says where PME is concerned the earthing conductor shall also meet csa of MPB in 544.1.1

unless I am misinterpreting that reg

 

[The General]

only thing you got wrong there is the value of t. if it's a 100A BS88-3, t would be 0.2. an 80A fuse would be 0.1 ( fig. 3A1, BGB), so trhat would give you an even smaller csa for the MEC.

Thanks!

 

[The General]

542.3.1 which in turn points to 544.1.1

Now although 5441.1.1 refers to bonding conductors, 542.3.1 also says where PME is concerned the earthing conductor shall also meet csa of MPB in 544.1.1

unless I am misinterpreting that reg

So, by that argument, there was a 16mm neutral, so 10mm main earth is the minimum (which in this case, it was)

 

[telectrix]

542.3.1 which in turn points to 544.1.1

Now although 5441.1.1 refers to bonding conductors, 542.3.1 also says where PME is concerned the earthing conductor shall also meet csa of MPB in 544.1.1

unless I am misinterpreting that reg

right, and i interpret that as being min. 10mm, as is the MBC. the reg. is poorly worded IMO.

 

[spark 68]

So, by that argument, there was a 16mm neutral, so 10mm main earth is the minimum (which in this case, it was)

What I was saying was you cannot always use the Adiabatic for PME, as it is subject to minimum sizes, of course for the larger sizes (subject to the minimum allowed) you can.

The smallest size of MPB in your case is 10mm^ , so I would expect a MEC to be at least that size, even though it may calculate out as being lower. In your case it works out that 10mm^ for the MEC is also greater than S/2 for the tails at 16mm, which is quite nice too.

 

[Eggster71]

Just my 3 pence worth. They had an eicr done and rcd protection was given a code 3.

Does the bathroom supplementary bonding include any electrical supplies in it? If not I'd probably code 2 that one.