Sub main advice please

[westward10]

Okay I have removed and tidied up some of the posts. Can we try and be respectful to one another and keep the thread on track. Thank you.

 

[mossep]

Hi

Depending on your installation method you could get away with a 63A MCB in the existing board if it has space, assuming your Zs at the new board is fine. You might get discrimination issues, but it’s hardly a critical installation that will cause life threatening issue if it does happen - you will have to have a think about that and any issues it may cause. Someone else mentioned fitting a fuse carrier rather than an MCB, thats a good idea if you can.

You could put a Henley block in and split the tails like you suggested, but there should be 1 point of isolation for the whole installation, so you might create more work doing it that way. In my experience, the majority of domestic customers want a cheap job rather than a well specced job.

Your 16mm T+E should be fine with regards to earthing, presuming its not being used as a bonding conductor. If it is being used as a bonding conductor then it will need to be sized appropriately. Is there services in the new area that need bonding, or are they supplied by plastic pipework?

 

[bigspark17]

Okay I have removed and tidied up some of the posts. Can we try and be respectful to one another and keep the thread on track. Thank you.

Youve changed your tune haha

 

[Matthew]

Mossepp - thank you for your detailed reply. My preference would be to split mains and add an isolator so will price up both methods! As for bonding - no - the new installation in entirely plastic pipe.

 

[MDJ]

Isolator? you will need an OCPD for the circuit, why 16mm2? did you calculate the load required? I bet that is overkill, also why a joint in a new cable run? have you got test equipment? there are plenty of other answers needed to the questions already asked to be fair.

 

[Octopus]

You could put a Henley block in and split the tails like you suggested, but there should be 1 point of isolation for the whole installation,

Really ............ reg number please?

 

[mossep]

Isolator? you will need an OCPD for the circuit, why 16mm2? did you calculate the load required? I bet that is overkill, also why a joint in a new cable run? have you got test equipment? there are plenty of other answers needed to the questions already asked to be fair.

I would imagine the joint is because it easy to terminate an SWA in an external adaptable box, and then run T+E internally to the fuse board. Not that uncommon really, aesthetically it might even look better on the outside wall as you'll struggle to put a neat bend in a 16mm SWA as it goes through the wall. Assuming its been done right what problems do you see with having a joint?

 

[mossep]

Really ............ reg number please?

462.1.201

 

[Baddegg]

What book is that in mossep?

 

['mr2'gd4u]

Why an isolator? It needs an OCPD not just a switch.

Nah... I was going to suggest a 10a light switch!! Lol

 

[mossep]

This book

 

[mossep]

View attachment 44956

 

['mr2'gd4u]

What book is that in mossep?

Bbb p121

 

[Baddegg]

Bbb p121

Thanks, wasn’t taking the pi$$ I’m still on the byb and couldn’t find it...

 

[mossep]

Its in the BYB too, not sure what page though but probably a similar reg number.

 

[Spoon]

Its in the BYB too, not sure what page though but probably a similar reg number.

537.1.4 A main linked switch or linked circuit-breaker shall be provided as near as practicable to the origin of every installation as a means of switching the supply on load and as a means of isolation.

A main switch intended for operation by ordinary persons, e.g. of a household or similar installation, shall interrupt both live conductors of a single-phase supply.

BYB page 154

 

[MDJ]

Nothing wrong with a Joint if it is done right, and if there is no other way, I don't think the job has been planned properly at all, a 16mm2 armoured and 16mm2 t&e for a very small out building with one ring a heating mat and a couple of lights, plus direct connection to an isolator and no OCPD is of concern, I appreciate the OP is very inexperienced and such should answer questions aimed at him by the other guys on here, I have seen him post since these questions and not answer. Has he concidered RCD protection for example, what type of earthing arrangement, is it notifable work? a lot to take in for a very basic job, hopefully he will start again and let us all into his thoughts so we can try to help properly. By the way that Bob the Builder book isn't great, I have the set, that story is one of the worse ones

 

[mossep]

Its might not be great, but it helped me build my loft extension!

 

[Baddegg]

537.1.4 A main linked switch or linked circuit-breaker shall be provided as near as practicable to the origin of every installation as a means of switching the supply on load and as a means of isolation.

A main switch intended for operation by ordinary persons, e.g. of a household or similar installation, shall interrupt both live conductors of a single-phase supply.

BYB page 154

Thanks spoon I’ll be in there later.

 

[Baddegg]

Its in the BYB too, not sure what page though but probably a similar reg number.

Thanks mossep