Running T&E in conduit

[parm]

Hi Guys,

I've been asked to do a surface mounted ring mains in a residential property, is it normal practice to leave the wires loose in the conduit or would you tie wrap them together or use something else? Thanks in advance from a newbee

 

[Amp David]

Keep then loose then if one need pulling back in the future you're OK

 

[Hawk81]

Tie wraps will only make it difficult to get the cables down the conduit. leave them loose.

 

[Sintra]

Agree always leave cables untaped in conduits.

 

[parm]

Thanks to all of the above guys

 

[malcolmsanford]

Are you really running T & E or was that a miss post. Also if you haven't done it before wiring a ring final circuit in conduit takes a bit of thinking through as you need to get your return leg back, I assume through the same outgoing conduit.

A way was pull 1st leg into 1st socket, 2nd leg into 2nd socket, 1st then to 3rd, 2nd to 4th etc using the boxes as pull throughs

 

[Guest123]

As it's a residential property I'm guessing he means mini trunking for the drops???, otherwise it'll be a bit of a job pulling through conduits.

 

[malcolmsanford]

I wouldn't fancy 4 x 2.5mm^ in conduit..............

 

[parm]

unforunately its going to be the entire ring in conduit, customer doesn't want boards up!! not looking forward to it, may see if I can suggest using slightly bigger conduit

 

[malcolmsanford]

boards up??

 

[m4tty]

That's gonna look nice mate conduit running around the living room. Lol

 

[parm]

I know, glad its not my place.....landlord decorated before getting PIR may take a picture and pop it on the site

 

[millwall ken]

Why would you pull T & E cables though Conduit? What about heat dissapation? The BRB states that the capacity of Trunking/Conduit should not exceed 45%.

 

[parm]

OSG and BRB state 45% space occupancy for heat discipation for single core cable which I agree with, however running 2.5mm thorugh conduit (2legs) will give a cable factor of 143 and I was planning to ussing 50x38mm conduit which has a factor of 767. So I suppose as my calculation is not strictly speaking correct, I thought around a 20% space occupancy for T&E would be fine....happy to be corrected

 

[Guest123]

As I suspected......you are referring to square/oblong mini trunking with a base and lid, as opposed to solid round conduit (pipe).

 

[parm]

Yes I am referring to the square trunking with the lid, apologies for not being clear

 

[Guest123]

So to clarify, are you running cables through the floorspace with the vertical drops to socket outlets in surface mini trunking???

If so the usual size that is used for a drop containing 2 x 2.5mm T&E's is known as MT2 which is 25x16mm in size.

 

[parm]

Thank you for clarifying the trunking size Lenny.........being very conservative by having larger conduit for heat discipation. Another newbee question bites the dust, thank you again

 

[martysparky]

do you mean this

Miniature trunkingRapid Electronics - Cables & Connectors > Cables

or this

PVC Conduit Round Light Gauge - 20mm x 3M - White - QVS Electrical Supplies | Electrical Wholesaler

 

[martysparky]

gosh missed that lol

 

[parm]

Cheers again!!

 

[La Poste]

OSG and BRB state 45% space occupancy for heat discipation for single core cable which I agree with

How about if your singles fill more than 45% because the conduit is small.
The singles are for the same circuit.
Would you use correction factors or would you have to dig out the conduit and start again?

 

[parm]

Sorry, I'm not sure I follow. If I use the correct factors that will give me the minimum size of trunking and then i will probably go up a size. Happy to be corrected the idea is that if I use twin and earth in conduit when they redecorate the wire will be in the right zones with enough slack. Albeit it will look horrible until then. Let me know what you think and if theres a better way of doing the job. Cheers

 

[La Poste]

This 45% rule, how many people really stick to it.
The last re-wire I did with my boss we used 20mm oval in the walls from the floor above down to the light switches below.
My boss put three 1.5 Tand E lighting cables in the oval. Also he used 20 mm oval for the drops to the sockets and put two 2.5 T and E in it.
I have worked with other sparks who use capping and put two cables in the capping hence filling the capping right up.
The trunking coming down to the main fuseboard is four by two usually filled to more than 45%.
So is everything I have seen my boss and this other sparks doing wrong so far?
Cheers.

 

[La Poste]

This 45% rule, how many people really stick to it.

Bump bump.

 

[Adam W]

In my experience the number of cables that go in any kind of containment is governed by how many cables you can cram in there.
Of course it's easier if you don't overfill, but the reality is many people guess rather than reach for the book.

 

[Traineenoob]

just hammer the lid on!!

 

[MDJ]

Hi Guys,

I've been asked to do a surface mounted ring mains in a residential property, is it normal practice to leave the wires loose in the conduit or would you tie wrap them together or use something else? Thanks in advance from a newbee

DIY Forum?

 

[MDJ]

is it normal practice to leave the wires loose in the conduit or would you tie wrap them together

T&Es, serious?

 

[MDJ]

I love it when we ressurect these old threads, worth a giggle for sure