10mm T&E for Consumer unit supply

[Sav]

Morning everyone,

Hope your all well.

Just a a quick question. We have been asked to quote for a HMO conversion, in a domestic property. So basically, the developer buys these houses and makes rooms out if them.
Leach room is basic, small ensuite shower ( not electric ), lights and a few sockets. There is a communal kitchen and each room is supplied by its own consumer unit.
There are 2 circuits, lights and sockets.
What I'm asking is, the consumer units are fed via 10mm T&E that go down to 60A isolators, which in turn go into a big Henley block.
There are about 5 rooms, so five isolators.
I would have thought that the consumer units for each room , from the isolators had have 16mm earth ?
Obviously things like communal smokes and fire alarm system etc are fed from landlord board.
The supply is a TN-S single phase

regards,
sav

 

[Zebra Stripe]

None hopefully, but they still occur now and again. IMO the best way is Switch fuse (Rating to suit), SWA sub to small CU with RCBOs.

 

[D Skelton]

None hopefully, but they still occur now and again. IMO the best way is Switch fuse (Rating to suit), SWA sub to small CU with RCBOs.

Cost allowing I agree, but we're talking HMOs here, they want it all for nothing. Therefore front end MCBs make the job a lot cheaper but still comply.

Answer me this; when you're taking a feed for a garage DB, do you HRC that or do you take it from the existing DB?

 

[Zebra Stripe]

I couldnt agree more, cost is important and would be the difference winning or loosing the job, but to be honest I've got no idea what HMOs are...her majestics office? Her majesties orders??? Himmlers marching orders??
I suppose HRC fuse carriers in a metal clad main board would be cheaper than a number of switched fuses.

 

[Andy78]

I couldnt agree more, cost is important and would be the difference winning or loosing the job, but to be honest I've got no idea what HMOs are...her majestics office? Her majesties orders??? Himmlers marching orders??
I suppose HRC fuse carriers in a metal clad main board would be cheaper than a number of switched fuses.

House of multiple occupancy. Separately rented bedrooms with shared bathrooms and kitchens.
I.e. student house setup.

 

[Zebra Stripe]

How embarrising I thought they were somethng to do with the military or crown....HMO = house in multiple occupation.....oh dear I really must start paying attention

 

[GLENNSPARK]

cost is important but compliance always comes first...as does good design/practice...

 

[guest119]

There may be access issues also re tripped devices, ones which require landlord only access.

Boydy

 

[D Skelton]

I couldnt agree more, cost is important and would be the difference winning or loosing the job, but to be honest I've got no idea what HMOs are...her majestics office? Her majesties orders??? Himmlers marching orders??
I suppose HRC fuse carriers in a metal clad main board would be cheaper than a number of switched fuses.

House of Multiple Occupancy.

You're right, I'd love to know where to find somewhere to purchase new wylex rewireable fuse boxes though!

 

[Zebra Stripe]

Just re-use an old one and repair any damage to the original enclosure. Im sure most are still good for another 20 or so years service.



Only kidding!!

 

[Guest55]

i like how everyone automatically throws in the demand for swa just because the word "submain" is used.

really ? for internal wiring in a domestic dwelling ??
and of course we're all going to chase in this oversized cable with additional labour costs of --- pounds...........

this job is so simple its beyond back of smoke packet design.........

dno cut out >>>> tails to 6 way 100A CU >>>>> 5 ways for bedsits , 1 for landlord >>>>>>>> 40A mcb >>>>> 6mm T&E >>>>>> 4 way CU in bedsits >>>>>> 20A skts + 6A lts.

and as the upstream device is double the rating of the highest downstream , you've even got decent chance of discrimination.

 

[D Skelton]

Just re-use an old one and repair any damage to the original enclosure. Im sure most are still good for another 20 or so years service.

I don't tend to keep old gear that I rip out, let alone sell it lol.

I stand by what I say. MCB's up front. Without that you're looking at 5 x switchfuses, 5 x 45A HRCs, 6mm SWA cable and a lot of bother.

The fact remains, the installation of MCBs up front is perfectly compliant and gives more than adequate discrimination for overload purposes. In the unlikely even of a short circuit on a brand new installation, then the main DB would just have to remain accessible wouldn't it.

Spec switchfuses, lose the work, it's really that simple.

 

[Zebra Stripe]

Ok. The set up his current electrician has is as follows

single phase TNS 100A BS1361. Tails into single meter.
From there into Henley blocks using 25mm tails.
From Henley blocks, 25mm tails into Mk60A isolator.
From isolator 10mm T&E ( presume buried in wall & under floor etc into consumer unit.
Consumer unit has 30ma RCD main switch and 2 circuits. Lights and sockets.
I also would have though swa from isolator into consumer unit.
But I would use 16mm ??
bonding as far as I could see is main gas and water in 10mm. I couldn't see an earth from the metal isolators to the MET though. Also couldn't see any supplementary bonding in the rooms. That's why the alarm bells rang in the head.
But I don't think 10mm T&E is the way to go ?
Sav

Well, you have to go by what was asked surely, in this case he was saying presume burried in a wall

 

[Zebra Stripe]

I don't tend to keep old gear that I rip out, let alone sell it lol.

I stand by what I say. MCB's up front. Without that you're looking at 5 x switchfuses, 5 x 45A HRCs, 6mm SWA cable and a lot of bother.

The fact remains, the installation of MCBs up front is perfectly compliant and gives more than adequate discrimination for overload purposes. In the unlikely even of a short circuit on a brand new installation, then the main DB would just have to remain accessible wouldn't it.

Spec switchfuses, lose the work, it's really that simple.

Hey I like the selective quote...makes me look a bit rogue'ish...so tell me why suddenly on the attact? its all opinion if compliant to BS7671 or some other suitable Regulation

 

[D Skelton]

Hey I like the selective quote...makes me look a bit rogue'ish...so tell me why suddenly on the attact? its all opinion if compliant to BS7671 or some other suitable Regulation

It was meant in jest my friend

I know it is all opinion, that's why I value discussions such as these

 

[Zebra Stripe]

Oops:lipsrsealed2:

Hey thats why Im banned from texting especially when trying to get into some women's ........

So just out of interest, and I am by no means fluent in this aspect, but, Im led to believe that discrimination or even partial discrimination is not possible between MCB and MCB.