Large house advice

Looked at a large house today total rewire and extras in that customer turning outbuildings well one of them into a flat.

60A income tns system

7 bedrooms

2 kitchens

3 shower rooms

Customer having major refurb, wants around 80 spots around the place for lights plus normal light fittings, 3 shower rooms will have 9.5 kw rated showers plus 2 x 32 amp supplies for cookers. And about 95 double sockets plus spurs off ring switched to run kitchen appliances dishwasher x 2,  fridge etc etc.

Flat supply only small about 80 feet away so was thinking 16mm swa off Henley block fused down then on to its own c/u

Was thinking about 5 ring mains plus splitting the lights into 5 circuits. 

How the he'll do I do max demand on this lot, incomer gotta be uprated can you still get 125A Uprate can I get away with 100A. 

Adevice thoughts please Team.

Definitely get a separate supply installed for the flat.

See if a 3 phase supply is available for the house, that's the only way you are going to come close to getting a properly rated system with three showers. It should be available but the price might be the issue (it would be a BIG job to get 3 phase here)

Or tell them to forget electric showers and get a really decent sized unvented hot water cylinder and have really decent thermal mixer showers.

My initial thoughts...

Dump the idea of ring circuits bar the kitchen/utility.

16A or 20A radials across 1 or 2 rooms.

How many rooms over and above those already listed?

How may floors?

How many people expected?

Can't run a 16mm SWA direct to a henley block as you can't terminate it correctly

I would probably do more than 5 light circuits, say one per 2 or 3 rooms.

Make sure that the spots are LED, and all other lighting where possible is LED.

Use RCBO's.

I am guessing the supply is TN-C-S?

contactors for the showers? or at least 2 of them? 

like SW says radials much better for the  room sockets you may need to use 4mm t&e.

Sorry guys TN-C system  60A bullet

Dont think they would pay for 3 phase could find out. Could cut 2 x showere out,  if they had a bigger combi in as thats there having. 

Sidewinder said:

My initial thoughts...

Dump the idea of ring circuits bar the kitchen/utility.

16A or 20A radials across 1 or 2 rooms.

How many rooms over and above those already listed?

How may floors?

How many people expected?

Can't run a 16mm SWA direct to a henley block as you can't terminate it correctly

I would probably do more than 5 light circuits, say one per 2 or 3 rooms.

Make sure that the spots are LED, and all other lighting where possible is LED.

Use RCBO's.

I am guessing the supply is TN-C-S?

Click to expand...

 Was gonna split tails via Henley block then feed hrc fused double pole isolator then terminate swa into that i.e kmf switch etc fused

You really don't want a combi in a house of that size. 

Cannot remember the last time i wired a ring main ( forget the sneering...it IS a ring main and always was....same as green sleeve and meggering, deal with it!)

also, depending on amount of insulation the cables run through you  may get a bit of a surprise when you see how much derating  is applied!

4mm radial on a 16A MCB............dont think it wont happen

just saying

Ampsyaman said:

 Was gonna split tails via Henley block then feed hrc fused double pole isolator then terminate swa into that i.e kmf switch etc fused

Click to expand...

Just a big house, ground floor, upper floor, loft  dining room plus lounge.

Sharpend said:

You really don't want a combi in a house of that size. 

Click to expand...

Have advised against, they looking into it, but hey how I'm not the plumber who quoted. Lol

kerching said:

Cannot remember the last time i wired a ring main ( forget the sneering...it IS a ring main and always was....same as green sleeve and meggering, deal with it!)

also, depending on amount of insulation the cables run through you  may get a bit of a surprise when you see how much derating  is applied!

4mm radial on a 16A MCB............dont think it wont happen

just saying

Click to expand...

Always wired ring mains suppose it was how it was back in the day, so what's the crack one ring main rest 4mm radials 20A rated can you get 2 lots 4mm in a socket 

Yes 2 lots is fine in most sockets even craptree!

And there was me thinkin that a ring main was a term the DNO's used for their ring circuits.... :tongue in cheek

Radials much better IMO, rings are a pain in the butt.

You should easily get upgraded to a 100 amp supply which will be ample for this place. 

Looked at rough itinerary of power to be consumed taking into account diversity factors on cookers etc and roughly what the customer has listed he must have, Inc 2 showers, 2 x super cookers, plus a multitude of power eating monsters that will have to be rated at 100%  some items gonna need 16mm t&e on his list. 

Boom 308 Amps

Tree phase me tinks. 

Nahh, Dai Varsity the Welsh sparky is your friend!

I would wager that it would run on a 100A 1ph supply.

Yes it  could pop, and, yes a TPN 100A/ph would be better, but...

Lol, put some candles on, run the gas it won't blow lol,  the list just goes on the enterprise would blow a fuse I rekon ha ha ha ha. Having g a massive unvented system in now just been told but having 3 x electric showers. Plus 2 x cookers and 2 x induction hobs plus electric ufh system, plus workshop plus apartments at the side. Oh lord oh lord the meter will be spinning around said kylie

More swearing I'm afraid...

https://www.youtube.com/watch?v=ut5DXxK1dvk

Awsome stuff 

I wired a place like that over 2 years, it's on a 100amp supply, nothing ever blows, people just don't use that much electic all at the same time, and cos they are wealthy, they eat out a lot anyway

binky said:

I wired a place like that over 2 years, it's on a 100amp supply, nothing ever blows, people just don't use that much electic all at the same time, and cos they are wealthy, they eat out a lot anyway

Click to expand...

More than likely correct but on paper with the list I've been given, taking into account diversity it say blow blow blow like divine brown. Going with 2 of my fellow friends to check it out once more and talk to the client, wealthy or not it's gotta be right. Bloody rich, lol

What calculations have you used for diversity?

The OSG?