Dado 3 compartment or Maxi trunking - home office - use singles?

[a546345]

I'm turning a 2m x 4m room into a home office, and I want to distribute the following around the room.

1. Normal sockets for computer monitors chargers fed from a 20A RCBO functionally switched by a 20A grid switch. Probably 6 double sockets

2. Second set of sockets for other devices fed from the same 20A RCBO all functionally switched by a 20A grid switch. Probably 4 double sockets

3. Sockets for floor/desk lighting fed from the same 20A RCBO functionally switched by a grid switch

4. Ceiling lights fed from the 6A downstairs lighting RCBO switched by another grid switch

5. Cat5e for network sockets

6. Line Audio/speaker cables

I was planning to use 3 compartment Dado trunking from screwfix, but then spotted that I could use Maxi trunking, any recommendations?

The trunking will be running at skirting level for most of the room, with a tee and riser to just above desk height and the grid switches.

I was thinking of running the various circuits in 2.5mm T&E radials from the CU which is about a 10m run. Then into an accessible plastic Adaptable box to convert to 2.5mm singles probably using Wago lever connectors. The singles then go to the grid switches and then onwards through the trunking to the sockets.

All of the network/audio cables would then go in the other compartment.

Does this sound reasonable? Anything I've missed? How are the single wires normally marked to show which circuit they belong to? Does the earth single need to be 2.5mm?

 

[PrenticeBoyofDerry]

Why do you require to go from t&e to singles?
Why the need for two circuits running from the same RCBO?
Why the need for grid switches and isolation?
How are you going about complying to the notification procedures?

 

[JohnW2]

Why the need for grid switches and isolation?

In all three cases, the OP said that he wanted the grid switches as functional switches, not for 'isolation'.

I agree with your other questions.

Kind Regards, John

 

[flameport]

10 double sockets presumably means you intend to connect at least that many devices - this is likely to cause problems if they are all connected to the same RCBO or RCD.

Does the earth single need to be 2.5mm?

It may need to be larger than that, or have more than one.

 

[a546345]

Hi all, thanks for the replies.

My thought process was that the singles are easier to run in the trunking than T&E and take up less room because they don't have the sheathing. And I've read lots about using singles in trunking. Would T&E be more appropriate?

I want to be able to switch off everything as I leave the room such as monitors, amplifier etc. Sometimes I'll want to leave some items running, eg. battery chargers, but not always.

These are existing circuits - what would need notifying?

All the devices are already plugged in to various 4 ways on the standard "upstairs sockets" ring and are not tripping the RCBO today.

Hi Flameport, looks like I need to read more - could you elaborate, or point me in the right direction please?

Cheers!

 

[JohnW2]

10 double sockets presumably means you intend to connect at least that many devices - this is likely to cause problems if they are all connected to the same RCBO or RCD.

I understand the theoretical concern, but I have to say that I have had a lot more than 10 items of IT equipment etc. (including several PCs, several monitors and printers) protected by the same RCD for very many years and, as I'm pretty sure that that RCD has never operated.

Kind Regards, John

 

[a546345]

oh-just to clarify:-

I was expecting to run 3 singles for each socket circuit, ie. live, neutral, earth. So that would be 3 for socket circuit 1, 3 for socket circuit 2, and 3 for the lighting sockets in the trunking. The ceiling lighting circuit could be T&E because that wouldn't go all the way round the room in the trunking.

 

[flameport]

The RCBO / RCD might not trip, but there is also the issue of the protective conductor current in the circuit:
http://electrical.theiet.org/wiring-matters/26/5437-earthing.cfm?type=pdf

 

[PrenticeBoyofDerry]

Why the need for grid switches and isolation?

In all three cases, the OP said that he wanted the grid switches as functional switches, not for 'isolation'.

Do socket outlets and light switches have provisions for functional switching?

 

[PrenticeBoyofDerry]

oh-just to clarify:-

I was expecting to run 3 singles for each socket circuit, ie. live, neutral, earth. So that would be 3 for socket circuit 1, 3 for socket circuit 2, and 3 for the lighting sockets in the trunking. The ceiling lighting circuit could be T&E because that wouldn't go all the way round the room in the trunking.

But why do you feel this is necessary?

 

[PrenticeBoyofDerry]

oh-just to clarify:-

I was expecting to run 3 singles for each socket circuit, ie. live, neutral, earth. So that would be 3 for socket circuit 1, 3 for socket circuit 2, and 3 for the lighting sockets in the trunking. The ceiling lighting circuit could be T&E because that wouldn't go all the way round the room in the trunking.

But why do you feel this is necessary, there will be no issue in using t&e?

 

[PrenticeBoyofDerry]

These are existing circuits - what would need notifying? "I was thinking of running the various circuits in 2.5mm T&E radials from the CU which is about a 10m run."

Your opening post seemed to suggest that you where running new circuits, ie from the CU?
even if existing you still legally require to prove what you have done is safe.

 

[333rocky333]

Even if you did go from T+E to singles rather than use wagos, change at the relevant accessory instead, less joints the better.

I am a firm beleiver all singles in containment or tube should be of same csa for L+N+E at least when under 6mm

 

[a546345]

Hi Prentice, yes, you are right, I did say that, because I was originally thinking of making "socket circuit 2" a new circuit which would then need notifying. I am aware of the testing requirement for changes to existing circuits.

I'll stick with T&E then if I go ahead.

ref earthing, thanks for the link, there is no industrial equipment, all domestic and portable, so nothing designed with 3.5mA leakage or higher.

 

[JohnW2]

In all three cases, the OP said that he wanted the grid switches as functional switches, not for 'isolation'.

Do socket outlets and light switches have provisions for functional switching?

I'm not really sure that I understand the question, or your point. As I understand it, the OP wishes to have three sets of sockets, each with a 'functional switch' to switch off all the sockets in that set in one go. If the OP wants/needs such functionality of his 'functional switching', I see no problem (I have similar arrangements in some parts of my house - e.g. to have a single switch for a particular group of items, the 'functional switches' usually being FCUs). The fact that he wants to use a grid switch for the ceiling light is presumably a matter of personal choice, maybe to achieve consistency with the other grid switches.

Am I perhaps missing the point of your question?

Kind Regards, John