sizing containment for T&E

[atm84]

Does anyone have experience sizing cable tray/ basket and trunking which is used for twin and earth cabling?

The on site guide only provides guidance and factors where single core PVC cables are used.

I am looking for help where twin and earth is used.

 

[shanky887614]

? t+e on basket and in trunking why? thats a new one on me.

yy,fp,flex etc is what you should be using in that containment

 

[atm84]

sizing containment for T&E

Twin and earth is cheaper than yy and flex. Quicker to install than singles.

 

[Pete999]

Does anyone have experience sizing cable tray/ basket and trunking which is used for twin and earth cabling?

The on site guide only provides guidance and factors where single core PVC cables are used.

I am looking for help where twin and earth is used.

What sort of trunking, plastic, metal can't understand why you would want yo run T&E in trunking unless it was for switch drops etc

 

[amlu]

cut a 10cm piece of containment, fill up with pieces of t+e and see how many will fit?

 

[atm84]

Does anyone have experience sizing cable tray/ basket and trunking which is used for twin and earth cabling?

The on site guide only provides guidance and factors where single core PVC cables are used.

I am looking for help where twin and earth is used.

What sort of trunking, plastic, metal can't understand why you would want yo run T&E in trunking unless it was for switch drops etc

I was mainly thinking of basket but wondered how trunking would be sized with T&E. I have come across it on some supermarket installs.

 

[shanky887614]

I was mainly thinking of basket but wondered how trunking would be sized with T&E. I have come across it on some supermarket installs.

only cowboys or house bashers put twin in trunking.

 

[Sintra]

I can understand the use of basket for t&e but certainly not trunking. No point in it whatsoever.

 

[atm84]

I was mainly thinking of basket but wondered how trunking would be sized with T&E. I have come across it on some supermarket installs.

only cowboys or house bashers put twin in trunking.

Why is that then?

 

[Silly Sausage]

I can understand the use of basket for t&e but certainly not trunking. No point in it whatsoever.

Aesthetics :smilielol5::smilielol5::smilielol5::smilielol5:

 

[telectrix]

only cowboys or house bashers put twin in trunking.

so what about T/E in basket or tray above suspended ceiling in offices with the drops in trunking?

 

[Dcf]

only cowboys or house bashers put twin in trunking.

I've just finished a 1.5 storey extension on Monday with a cinema room downstair
ran basket on brackets in the coomb with 1x for power t&e and1x for data hdmi ,speakers etc
reason?
i didn't want it all covered in 4ft of insulation and I wanted to keep the power and data stuff as far apart as possible .
looked very neat and tidy and was easy to install
and I didn't have to clip a shed load of cables to every joist.
so am I a cowboy or house basher then?

 

[atm84]

sizing containment for T&E

I appreciate all the comments but as usual the thread is going off on a tangent. Does anyone know a reasonable method for sizing containment for T & E?

 

[LeeH]

Post #9 gave it to you.

Use a length with a bend on and see how much will comfortably fit in.

 

[Silly Sausage]

Re: sizing containment for T&E

I appreciate all the comments but as usual the thread is going off on a tangent. Does anyone know a reasonable method for sizing containment for T & E?

Look at page 138 of your Green OSG.

 

[telectrix]

basket or tray, just use trhe rating factors e.g. cables touching/separated, etc. for trunking, use common sense. rate cables according to method B and don't overcrowd the trunking.

 

[atm84]

basket or tray, just use trhe rating factors e.g. cables touching/separated, etc. for trunking, use common sense. rate cables according to method B and don't overcrowd the trunking.

I'm not looking to size the cable, I'm trying to ascertain how many cables can fit on the basket/ tray or in the trunking.

 

[Plonker 3]

OP until you provide how many and what size t&e you are referring to you will not get a answer. At the minute your question is equivalent to how long is a piece of string.

 

[atm84]

I appreciate all the comments but as usual the thread is going off on a tangent. Does anyone know a reasonable method for sizing containment for T & E?

Look at page 138 of your Green OSG.

Like I already stated the OSG only provides guidance for single core cables.

 

[atm84]

OP until you provide how many and what size t&e you are referring to you will not get a answer. At the minute your question is equivalent to how long is a piece of string.

Its a generic question. how dies one calculate how many Twin and Earth cables can fit on x size cable tray. Yes I know you can work out the diameter if the cable and multiple, but in reality cables are not butted right up to each other. Is there a factor that is applied.

 

[telectrix]

Like I already stated the OSG only provides guidance for single core cables.

so use the same tables. you won't be far out. as to how many cables, basically there should be approx. 50% cable and 50% airspace in the trunking. or.................. when you can't get the lid on, you know it's too full.

 

[Simonslimline]

Like I already stated the OSG only provides guidance for single core cables.

Maybe re read it perhaps!

 

[atm84]

Like I already stated the OSG only provides guidance for single core cables.

so use the same tables. you won't be far out. as to how many cables, basically there should be approx. 50% cable and 50% airspace in the trunking. or.................. when you can't get the lid on, you know it's too full.

How can you use the same tables when its completely different type of cable.

Come on guys do any of you actually carry out design work or do you just guess and hope for the best.

 

[atm84]

Like I already stated the OSG only provides guidance for single core cables. Get your facts right before patronising me.

Maybe re read it perhaps!

Yep re read it. Still says the same. For single core cables

 

[Plonker 3]

Its a generic question. how dies one calculate how many Twin and Earth cables can fit on x size cable tray. Yes I know you can work out the diameter if the cable and multiple, but in reality cables are not butted right up to each other. Is there a factor that is applied.

Well seeing as neither the BGB or OSG have any info regarding this then no there isnt.

 

[atm84]

sizing containment for T&E

Lets hope the New BYB has. But I doubt it.

 

[telectrix]

like i said. use the tables for singles and assume T/E is poorer at heat dissipation due to it's sheath so derate by a factor that you determine using common sense. BS7671 is not the bible.( even if IET think it is)

 

[Simonslimline]

Yep re read it. Still says the same. For single core cables

What book are you reading? My OSG (Green) talks about other sizes and types of cable. Bottom of page 138.

 

[atm84]

like i said. use the tables for singles and assume T/E is poorer at heat dissipation due to it's sheath so derate by a factor that you determine using common sense. BS7671 is not the bible.( even if IET think it is)

Will you please re read the OP. I am not looking for cable size. I'm looking for tray size.

 

[atm84]

Yep re read it. Still says the same. For single core cables

What book are you reading? My OSG (Green) talks about other sizes and types of cable. Bottom of page 138.

I will ask you a very simple question. Does it tell you how to size cable tray for twin and earth cables?

 

[Plonker 3]

Have you ever tried applying common sense and finding out for yourself what you need to know?

 

[Simonslimline]

I was mainly thinking of basket but wondered how trunking would be sized with T&E. I have come across it on some supermarket installs.

You have asked about trunking though.

This is what i was getting at.

 

[atm84]

Have you ever tried applying common sense and finding out for yourself what you need to know?

Yes I have and it didn't get me anywhere.

 

[atm84]

I was mainly thinking of basket but wondered how trunking would be sized with T&E. I have come across it on some supermarket installs.

You have asked about trunking though.

This is what i was getting at.

It still doesn't say what factor to apply to Twin and Earth in trunking does it.

 

[Anthony S]

Have you got a job that need's doing ?

 

[telectrix]

if the cables hang over the sides, it's too small.

 

[Deleted member 72666]

Look! It's really simple, first decide if you're grouping these cables or are they to be spaced? Then measure said cables with or without spacing, choose tray/ basket and determine size and divide this by size and number of cables. It's not hard is it?

 

[VoltzElectrical]

How many cables? More information needed.

Also, @ the earlier posters that poo-pooed the twin and earth in trunking, I have worked on student accommodation where 4x4 trunking run around the ceiling/ wall joint and drops done in mini -trunking, wired in Twin. Also office space where all runs done in twin from DB up into attic space, along tray, boxed in drops in corners to skirting dado, etc..

Making generalisations just shows lack of real life situations.

 

[tazz]

Find this hard to believe....a construction company will have submitted a cable schedule and the design for containment...The normal schedule will always be for lsf singles in supported galv trunking, db armored on tray size to suit quantity plus future additions. And basket suited for data, and basket for fire/security. For all those who keep harping on about escape route containment, this is why designers have chose this method over the past 5 plus years

 

[Risteard]

The normal schedule will always be for lsf singles in supported galv trunking

Agreed. T&E in containment is an appalling practice really.

In fact generally T&E outside of a domestic premises is pretty poor.