5x 1.5mm - 25mm conduit

[LewisM]

Hi can you get 5 *1.5mm lsf twin and earth cables through a straight piece of 25mm with a bush and coupler?

 

[MJPD29]

Yes you can

It wants me to type more letters so yet again

Yes you can

 

[LewisM]

Yes you can

It wants me to type more letters so yet again

Yes you can

Thanks wasn't sure if the reduction in CSA because of the bush would cause an issue

 

[Lister1987]

I find myself asking why you're running T&E in conduit when that conductors aren't flexible?

 

[LewisM]

I find myself asking why you're running T&E in conduit when that conductors aren't flexible?

For aesthetics only, cables are running above a plasterboard ceiling then dropping down to accessories in metal conduit, seems to be the fashion now

 

[Vortigern]

You would have to look up the factors table for the conduit. Sounds like too many to me. Usually the factor tables are for singles on the cable factor parts.

 

[LewisM]

I know you design as per regs but will have 150w of lighting load going through it so don't think any heat will be generated and even so it will be negligible.

 

[Lister1987]

For aesthetics only, cables are running above a plasterboard ceiling then dropping down to accessories in metal conduit, seems to be the fashion now

If that is the case why not put an MF connection so that you have flexible conductors for the conduit? I get that OSG allows for flexible or solid conductors but it wouldn't sit right with me, probably just me though.

 

[Lister1987]

For aesthetics only, cables are running above a plasterboard ceiling then dropping down to accessories in metal conduit, seems to be the fashion now

If that is the case why not put an MF connection so that you have flexible conductors for the conduit? I get that OSG allows for flexible or solid conductors but it wouldn't sit right with me, probably just me though.

 

[MJPD29]

If that is the case why not put an MF connection so that you have flexible conductors for the conduit? I get that OSG allows for flexible or solid conductors but it wouldn't sit right with me, probably just me though.

Why does it not sit right with you? I'd be very interested to know why solid conductors are not suitable for conduit, as it would render every single home in northern ireland unsuitable

 

[DPG]

If that is the case why not put an MF connection so that you have flexible conductors for the conduit? I get that OSG allows for flexible or solid conductors but it wouldn't sit right with me, probably just me though.

Unnecessary joints with your method though.

 

[Lister1987]

Unnecessary joints with your method though.

True but you weigh up conductor flexibility Vs the joint, could be wrong here but I would garner that tht T&E manufacturer wouldn't endorse that installation method as tht conductors are the wrong class for the application.

I'm aware OSG has conduit fill details for solid v stranded.

 

[DPG]

True but you weigh up conductor flexibility Vs the joint, could be wrong here but I would garner that tht T&E manufacturer wouldn't endorse that installation method as tht conductors are the wrong class for the application.

I'm aware OSG has conduit fill details for solid v stranded.

A good argument. I've had too many beers tonight but may be back tomorrow.

 

[MJPD29]

True but you weigh up conductor flexibility Vs the joint, could be wrong here but I would garner that tht T&E manufacturer wouldn't endorse that installation method as tht conductors are the wrong class for the application.

I'm aware OSG has conduit fill details for solid v stranded.

Honestly you need a re-think here. I don't doubt you have a lot of knowledge and know your books, but how much real world experience do you actually have? Have you honestly ever came across a situation where putting a twin and earth in a conduit would go against any manufacturers instructions? In almost every house here we use 20mm conduit instead of capping. Capping is more or less non existent here. Are you going to tell every spark that they should be putting a junction box above every single drop and converting the cable to stranded because the twin and earth is unsuitable to be in a conduit? Has the practice been wrong for the last 60+ years? I don't agree with your arguement in the slightest and I am not aware of (not saying it doesn't exist) of any written data that supports it

 

[James]

Honestly you need a re-think here. I don't doubt you have a lot of knowledge and know your books, but how much real world experience do you actually have? Have you honestly ever came across a situation where putting a twin and earth in a conduit would go against any manufacturers instructions? In almost every house here we use 20mm conduit instead of capping. Capping is more or less non existent here. Are you going to tell every spark that they should be putting a junction box above every single drop and converting the cable to stranded because the twin and earth is unsuitable to be in a conduit? Has the practice been wrong for the last 60+ years? I don't agree with your arguement in the slightest and I am not aware of (not saying it doesn't exist) of any written data that supports it

Agreed, twin and earth in conduit (rigid, not flexible) trunking, ducting, etc not a problem for me.

only issue you may have is drawing it through a conduit with multiple bends due to it not flexing well.

 

[7029 dave]

Agreed, twin and earth in conduit (rigid, not flexible) trunking, ducting, etc not a problem for me.

only issue you may have is drawing it through a conduit with multiple bends due to it not flexing well.

Dont think any issue's with straight drops, as intended like oval/capping. IMO multiple bends in conduit should be a full system hence stranded singles. Trunking included

 

[Lister1987]

Unnecessary joints with your method though.

True but you weigh up conductor flexibility Vs the joint, could be wrong here but I would garner that tht T&E manufacturer wouldn't endorse that installation method as tht conductors are the wrong class for the application

Honestly you need a re-think here. I don't doubt you have a lot of knowledge and know your books, but how much real world experience do you actually have? Have you honestly ever came across a situation where putting a twin and earth in a conduit would go against any manufacturers instructions? In almost every house here we use 20mm conduit instead of capping. Capping is more or less non existent here. Are you going to tell every spark that they should be putting a junction box above every single drop and converting the cable to stranded because the twin and earth is unsuitable to be in a conduit? Has the practice been wrong for the last 60+ years? I don't agree with your arguement in the slightest and I am not aware of (not saying it doesn't exist) of any written data that supports it

Hey I'm all for learning and better myself, you're right in that I don't have site experience and no doubt with that application of experience my mindset will change, it just initially doesn't sit right with me.

 

[7029 dave]

True but you weigh up conductor flexibility Vs the joint, could be wrong here but I would garner that tht T&E manufacturer wouldn't endorse that installation method as tht conductors are the wrong class for the application

Hey I'm all for learning and better myself, you're right in that I don't have site experience and no doubt with that application of experience my mindset will change, it just initially doesn't sit right with me.

So do as your told then ?

 

[Lister1987]

So do as your told then ?

SAt on the throne contemplating life and I've figured out what it is that bugs me about it (T&E in conduit); How do you factor in either the entire sheath (as in unstripped going through a conduit) or, where you've stripped the outer insulation, the 2 insulated and 1 sleeved core? Can't imagine the OSG tables factoring in whole T&E sheath?

Probably overthinking it or just being a numtpy but I figure I'm already invested in this, may as well go full numpty and not half-arse it

 

[loz2754]

From the IET:

However, it is important to remember that when determining the capacity of a conduit or trunking installation, it is for “drawing in” purposes only in order to prevent mechanical damage to the cables.

It is important to remember that where the type and size of the conductor are not identified in Table E5 and Table E6, the space factor should not exceed 35% for conduit and 45% of the internal CSA for trunking. Space factor is the ratio of free space to the number of cables installed.

I would personally conclude from this, that just because it may be possible to get 5 1.5 LSF twin and earth cables down a 25mm conduit, doesn't mean that it's okay to do so.