New Build Specs????

[mags1972]

Hi all,

Not done any New Build work for a while now, am I right in saying the spec should be:

• Minimum Socket Outlets as per Table 8B 17th Ed On Site guide
• 33% all light fittings to be low energy pendants or equivalent
• Extractor Fans in all Bathrooms and w/c's, if no opening window then they must incorporate a timed overrun and then a triple pole isolator.
• Seperate Lighting Circuit for each floor
• Seperate Ring Final Circuit for Each Floor and Kitchen
• Smoke Alarms for each floor and Heat Alarm for Kitchen
• Consumer Units to be mounted between 450mm and 1200mm

If I've missed anything or got anything wrong please feel free to correct me!
Thanks in advance guys!

 

[Spudnik]

Looks spot on to me.

Outside lights must be PIR operated or with photocell.

Also, be careful of cable sizes as EVERYTHING that is a void, is stuffed full of insulation.

 

[mags1972]

Looks spot on to me.

Outside lights must be PIR operated or with photocell.

Also, be careful of cable sizes as EVERYTHING that is a void, is stuffed full of insulation.

Thanks Jason, in ref to the ever growing insulation within houses for 3 storey houses would you consider a second consumer unit run in 16mm T&E fed from a B63A MCB in the main CU for the 3rd storey circuits?
Just a thought, wondered what your opinion was!

 

[Spudnik]

No need to run sub mains.

Just spec a CU big enough for all the circuits.

You could always run a 4mm radial for the top floor sockets if its just a couple of bedrooms etc, and 1.5 should be fine for the lighting.

Dont forget that zones permit cables to be run unprotected within 150mm of two adjoining walls, so your feeds can go straight up.

 

[mags1972]

No need to run sub mains.

Just spec a CU big enough for all the circuits.

You could always run a 4mm radial for the top floor sockets if its just a couple of bedrooms etc, and 1.5 should be fine for the lighting.

Dont forget that zones permit cables to be run unprotected within 150mm of two adjoining walls, so your feeds can go straight up.

Thanks for that Jason, a pleasure!!

 

[fog]

hi
didnt know the 450-1200 applied to cu
also the lights is 25% but check with building control, as last new build i did the architect said all lighting as deemed by the local building control yeap you can guess what they said all lights to be low energy only and pir outside with a max of 150w
i regularily use aico wireless interconnect smoke heat alerms, saves putting in another bit of 3 core also handy on 3 storey builds, and no rcd for the smoke circuit.
hope of some help

 

[mags1972]

hi
didnt know the 450-1200 applied to cu
also the lights is 25% but check with building control, as last new build i did the architect said all lighting as deemed by the local building control yeap you can guess what they said all lights to be low energy only and pir outside with a max of 150w
i regularily use aico wireless interconnect smoke heat alerms, saves putting in another bit of 3 core also handy on 3 storey builds, and no rcd for the smoke circuit.
hope of some help

Why no RCD for the smokes, as long as it goes on its own RCBO I don't see a problem, never heard of this one before!

 

[spoton elec]

all circuits buried less than 50mm requires rcd protection unless surface mounted this includes smoke detectors they need there own individual rcbo

 

[steamboatwilly]

25% for LE lighting I think?

Also, be careful of cable sizes in insulation (there's loads of this in new build walls/floors).

Height of CU is debatable....depends on circumstances.

Consider a permanent ventilation system (eg, Vent Axia multivent 250/350) instead of individual timed bathroom/utility fans?

 

[fog]

my apologies for the no rcd on smoke
no smoke on multiple rcd protected circuits, dedicated rcbo is perfect

 

[Spudnik]

Height of CU is debatable....depends on circumstances.

Height of Cu isnt debatable in new builds.

Its 450-1200mm from ffl.

 

[flukey]

Height of Cu isnt debatable in new builds.

Its 450-1200mm from ffl.

consumer units should not be installed where young children might interfere with them worth bearing in mind when you consider the 450-1200 rule

 

[Spudnik]

That could be in ANY house, so they would all be too high for part M

The reg still stands

 

[flukey]

That could be in ANY house, so they would all be too high for part M

The reg still stands

just quoting the statement out of electricians guide to the building regs mate

 

[Spudnik]

No i know

Must admit, although its a good book, some of it is questionable.