Circuit Metering

[LED Lighting]

Hi All

I have been asked to install a New DB to serve 40 offices, with the facility to meter each office individually.
I was thinking of installing a 18way TP&N DB, running 10mm to each office where a smaller SP CU is installed branching off to 3 circuits. Lights, Sockets and electric heater. A Din Rail Energy Monitor would be installed in this CU.

Whole install is in Dado and plastic trunking on the surface so RCD is in the office CU and not the 3P&N DB.


Any thoughts on this or any other way of doing it.

 

[LED Lighting]

The benefit is that you will actually be able to comply with the regulations concerning discrimination, which you won't be able to do with MCBs.

Can you point me to the regulation about this please. As I have not come across this one yet.

 

[LED Lighting]

would provide better discrimination. you will struggle to achieve discrimination between MCB's. For example a fault on the lighting circuit in the office could just as easily trip the MCB feeding the distribution circuit taking out the computers.

So am I right in saying, 1361 feeding DB, 1361 in DB feeding CU, and MCB/RCBO in CU??

 

[davesparks]

What do you mean about discrimination of over current protective devices?
There will be a 50A MCB in the DB, and in the CU there will be 32A - Sockets, 16A - Heater and 6A Lighting.
They wont even get anywhere near this.

The offices are single occupancy offices so they should not even use 20A day to day.

With respect, are you sure you are qualified to design an electrical installation of you don't understand the principal of discrimination of ocpds?

Look at the manufacturers data including tripping curves and times for the MCBs to see how they will discriminate

 

[Leesparkykent]

So am I right in saying, 1361 feeding DB, 1361 in DB feeding CU, and MCB/RCBO in CU??

yes or bs88.

 

[davesparks]

So am I right in saying, 1361 feeding DB, 1361 in DB feeding CU, and MCB/RCBO in CU??

BS88 fuses or correctly set MCCBs are what you need, bs1361 has been replaced/merged into bs88 now

 

[Simonslimline]

Have a gander at this. Guide to discrimination | edmundson-electrical.co.uk

 

[Leesparkykent]

536.1 page 151 BYB

 

[LED Lighting]

Edit: link didn't work

might be better to use something like these for the distribution circuits.

You suggested this one, but I am struggling to find anything bigger than a 32A.

I have found a 50A Single pole in India Hager Site but nothing on the UK Hager site.

 

[Leesparkykent]

You suggested this one, but I am struggling to find anything bigger than a 32A.

I have found a 50A Single pole in India Hager Site but nothing on the UK Hager site.

I don't think you will find a 1 module carrier over 32A. realistically do you think you need to provide 50A to each office?
you will find it easier with regards to metering with 32A distribution circuits IMO as that's what most 1module din rail mounted KWH meters are rated to. just my opinion...

 

[davesparks]

Try these
http://www.neweysonline.co.uk/mem-d...way-tpn/1050071940/ProductInformation.raction

https://www.sparksdirect.co.uk/24-w...-fuse-units-24-way-tpn-fuseboard#.VoA0ISOnxDs

 

[LED Lighting]

I don't think you will find a 1 module carrier over 32A. realistically do you think you need to provide 50A to each office?
you will find it easier with regards to metering with 32A distribution circuits IMO as that's what most 1module din rail mounted KWH meters are rated to. just my opinion...

Only concern I have is they will be running 5 Double sockets, 1 Heater (1.5KW) and a 40W LED Lamp.
I dont think the load will exceed 32A but it might get close if they have a kettle & heater on at the same time.

 

[Leesparkykent]

If you go down the route of fuse carriers like Davesparks has posted links to, also have a look at lucyelectric.

 

[LED Lighting]

Try these
Buy MEM Distribution Fuseboard, Exel, 63A, 8 Way, TPN - 608XTNC

https://www.sparksdirect.co.uk/24-w...-fuse-units-24-way-tpn-fuseboard#.VoA0ISOnxDs

Thanks but neither will be big enough, theres 40 offices, so needs to be 16 or 18 way TP&N

I was looking at the Hager or Havells 18Way DB, just need to find a suitable fuse carrier.

Does anyone have any concern about a 32A BS88 not being big enough for the demand? The calculations say it should be fine.

 

[Leesparkykent]

Only concern I have is they will be running 5 Double sockets, 1 Heater (1.5KW) and a 40W LED Lamp.
I dont think the load will exceed 32A but it might get close if they have a kettle & heater on at the same time.

how many computers per office?

 

[LED Lighting]

how many computers per office?

Theres 2 types of office.
Office 1: 1 Computer, 1 Heater (1KW) and lights. Total of 5 D Sockets
Size: 3m x 2.5m

Office 2: 2 Computers, 1 Heater (1.5KW) and lights. Total of 8 D Sockets
Size: 3m x 5m