Round vs oval conduit

[DJ12345]

Hello guys! Just quick question, whats better to be buried inside the wall? Round or oval conduit for easy cable management and replacement? I have seen people using round conduit inside the wall but i am not sure if they are right as i have heard from other people that are oval conduit. Whats your thoughts?

Thank you!

 

[7029 dave]

Ah..okay. When we wire a domestic house in conduit it's continuous PVC tubing between the back boxes so you can pull new wires between two sockets or switches or luminaires at any time in the future. Sounds like you don't use conduit that way. Are you guys using steel oval conduit drops as protection? I though that's what your cable zone rules were there for..??

In singles no doubt

 

[Marvo]

In singles no doubt

In singles or flat twin+e cable

 

[littlespark]

Oval is really just for drops…. So it’s our twin and earth cables as standard, and then run vertically through the oval conduit to the boxes.

Older houses could still have steel conduit and wired in singles… old imperial sized conduit.

 

[Simon47]

You don’t/ can’t bend oval conduit…

You can, but it's a p.i.t.a. to do.
Tape over one end, fill with sand, apply hot air from gun, and ease it round. The sand stops it just completely flattening, but it still needs patience. I find just heating the outside of the bend, and not doing it in one go (bend, straighten a little, bend, straiten a little, ...) helps as it allows the sand to settle a bit each time - if you are stretching the outside, it means the volume is increasing so need to allow the sand to settle and fill it.
Works bending either way - on the wide or the thin face.
We bother ? In our lounge I had to bend the conduits out of the wall and notch the wall plate - otherwise they'd just but onto the top face of the wall plate. In the hallway I needed a 90° bend from coming out the top of the switch backbox to going outside higher up for the outside light.
I hate not being able to alter the wiring, the amount I had to hack out of the plaster in the lounge was ... annoying.

 

[7029 dave]

You can, but it's a p.i.t.a. to do.
Tape over one end, fill with sand, apply hot air from gun, and ease it round. The sand stops it just completely flattening, but it still needs patience. I find just heating the outside of the bend, and not doing it in one go (bend, straighten a little, bend, straiten a little, ...) helps as it allows the sand to settle a bit each time - if you are stretching the outside, it means the volume is increasing so need to allow the sand to settle and fill it.
Works bending either way - on the wide or the thin face.
We bother ? In our lounge I had to bend the conduits out of the wall and notch the wall plate - otherwise they'd just but onto the top face of the wall plate. In the hallway I needed a 90° bend from coming out the top of the switch backbox to going outside higher up for the outside light.
I hate not being able to alter the wiring, the amount I had to hack out of the plaster in the lounge was ... annoying.

Surely it would have been easier to use 20mm round conduit (pvc) and use a spring

 

[brianmoooore]

I regularly work on houses where 600mm thick internal walls are the norm and 1000mm thick walls not unusual. Door frames tend to be set flush with one side or the other, which leaves the light switches on the non flush side effectively in a short tunnel.
For these situations I use corrugated 20mm round flexible conduit, following the 'safe' zone up from the switch, but from there on , to the ceiling in the room, chased in so far as to be out of the zone.

 

[Simon47]

Surely it would have been easier to use 20mm round conduit (pvc) and use a spring

Not when you are slotting it in between the brick courses to minimise the amount of hard red brick you need to drill.
Or when 20mm conduit would mean chasing the hard brick while oval will fit in the bonding depth.
Or you're using two 32mm ovals to allow for needed capacity. In that case, I ran them side by side up the wall, and carefully shaped them to be one over the other to minimise to hole I had to drill at around 45° through both skins of a brick wall.
Or ...

That's just the most recent ones that come to mind. In general, you are right, just use round conduit and a bending spring. But there are many situations where oval, and being able to bend it, is going to be a whole lot better.