Opinions please.

[Dave OCD]

I have an extension to wire this week which is a garage conversion comprising a study, shower room and small store area. The supply is TT and I'm intending on running a 16mm sub main from the existing mains position under the suspended floor through the hall in the house and installing a new small CU with RCBOs in the new store area. Due to the earthing arrangements I'll fit an S type 100ma RCD and 60a Switch-fuse [possibly 63a MCB] at the supply end, either seperate units linked by tails or integrated in one unit if I can source something suitable. Do you think these items should be Amendment 3 compliant as I don't think I've seen such a beast yet ? Any pointers to similar recently used kit would be welcome. :smilewinkgrin:

 

[Leesparkykent]

For the rcd enclosure you might have to use a two way board and a couple of blanks. Cant seem to find anything compliant.

 

[Dave OCD]

That's what I mean, I've been quoted similar...most wholesalers seem to be trying to rip the arse out if it. These ones are just as good, do exactly the same job and for under £2...cant complain at that.

I actually tried a standard 32mm Wiska plastic gland asan experiment with 16mm tails/10mm earth and found the insert squashes/compresses enough to seal it all up pretty well. [It would certainly meet IP4X]

 

[Dave OCD]

For the rcd enclosure you might have to use a two way board and a couple of blanks. Cant seem to find anything compliant.

That's what I'm thinking Lee, tempting to use a small compliant board with the S type as the main switch and a 63a MCB for the sub main, but compared to a fuse it could cause discrimination issues I think. :smile5:

 

[Leesparkykent]

That's what I'm thinking Lee, tempting to use a small compliant board with the S type as the main switch and a 63a MCB for the sub main, but compared to a fuse it could cause discrimination issues I think. :smile5:

That's the problem as even a 6A mcb will offer none to very little discrimination with the 63A mcb...in an ideal world you would put the distribution circuit on a fuse.

 

[Dave OCD]

That's the problem as even a 6A mcb will offer none to very little discrimination with the 63A mcb...in an ideal world you would put the distribution circuit on a fuse.

Yeah it'll have to be a fuse, I'm glad I priced this one adequately !

 

[Flanders]

Cant you use a type d mcb

 

[Leesparkykent]

Cant you use a type d mcb

Wont make a difference where discrimination is concerned.

 

[Leesparkykent]

http://edmundson-electrical.voltilink.co.uk/articles/guide-discrimination this is a good read.

 

[Flanders]

Thanks for that lee think i been miss guided in the past was thinking about discrimination for overload not short circuit .

 

[Dave OCD]

Cant you use a type d mcb

It did occur to me ,might be ok on overcurrent 'tripping' on one of the final circuits but in the event of a l-n short it would most likely go at the same time ?

 

[Dave OCD]

Beaten to it again !:biggrin:

 

[Amp David]

What brand of RCBOs you using in the new CU.? Always found DP versions tricky to get

 

[Leesparkykent]

What brand of RCBOs you using in the new CU.? Always found DP versions tricky to get

SBS do single pole switched neutral RCBOs.

 

[Deleted member 9648]

Is it an actually requirement that the door is hinged to shut itself? Just think if you had to install a 3phase board within a domestic property if this was the case.

No,it's not a specific requirement....but for me that is not complying with the intention of the regulation which is a fire resistant enclosure over all 'combustible' components as far as is practical. That is why all Am 3 designed enclosures I've seen have a top hinged metal lid. I wouldn't fit that wylex unit. I take your point about the 3 phase board,but that would easily be overcome by fitting 3 separate single phase DB's if you took the view that a side hinged door was not compliant. I would take that view as the door left open would negate any fire resistance of exposed 'combustible' components.

 

[Leesparkykent]

The hinged lid is a good idea but I've already seen a board installed where the wall was out and the lid ever so slightly stayed open. Imo a catch or similar is better. Edit: What switch fuse would you install? As there doesn't appear to be many on the market atm that meet the requirements.