pvc conduit

[padawan]

Hi guys I would just like to seek some clarification on running multiple circuits in conduit.


This is for a domestic installation, installing 2 new circuits, one of which is 6a lighting circuit and the other a 32 a ring main. Both circuits will be run in round pvc conduit which will be surface mounted.


Am i right that due to it being a domestic installation, and both circuits not running constantly at full capacity then there is no need to derate the cables, and that spacing factors are not really required? essentially as long the cables/conductors can all fit inside the conduit then there is no problems?


With regards to running the conduit i have a couple of questions about best working practices.


1. Do you suggest running both circuits in the same conduit system and then dropping down to the relevant sockets or light switches?


2. Is it better practice to run each circuit in there own independent conduit system?


3. What size conduit would i need to run a ring main and lighting circuit in the same conduit? will 20mm or 25mm do the job?


4. Is it ok to run T&E in conduit?

 

[davesparks]

Being domestic is irrelevant to both the swearing factor for grouping and the space factor.
However you are correct that due to none of the cables running at full rated current 24/7 you can reduce or negate the grouping derating factor.

How you run the conduit will depend on the layout of the job and type of cable used.
If it will be a complete conduit system then T&E will be pointless and a complete pita to install compared to singles. However if the conduit is only for part of the run with the rest being the usual clipped direct type methods then T&E would suit.

If it's a complete conduit and singles installation you'd normally install both circuits in one conduit. For one lighting and one rfc you would usually install a main run of 25mm conduit with 20mm conduits tee'd off from it for each switch, light, socket etc.

 

[Farmelectrics]

whats the reason for using pvc conduit why not twin and earth

 

[amlu]

whats the reason for using pvc conduit why not twin and earth

surface mounted twin and earth?

 

[Pete999]

Will this be a completely enclosed PVC conduit installation? if so use single cables, or are you talking about socket and switch drops chased in the wall?
You haven't answered Farmelectrics question, as to the reason you have opted for PVC Conduit, it will help us help you, if you explained your reasons.

 

[7029 dave]

How about using trunking and conduit for all drops and lighting points, I would use singles, without seeing the set up might not be practical, but just an suggestion.