galvanised trunking segregation

[apprentice123]

just a quick question about galvanised trunking in a commercial setting with regards to an assaignment ive been set by my college.
i have got a run of trunking running from a plant room in a car garage which will carry pvc singles for sockets lighting etc, alongside this i have to get 4 cat 5's and 3 fp200 cables for the fire alarm system. would it be acceptable to run all of the cables through the same trunking using galvanised filleting to segregate the voltage bands and segregate the fire cables? if it is how would i go about bringing the cables over one another when they need to cross over within the trunking?

 

[buzzlightyear]

you need to put in cable separators it depends witch cable you put in first .

 

[benji]

you would be looking at 3 compartment trunking prob. 150x50 and you could use manufactured cross-over tees ect. or you could just drill holes in bottom or sides and use conduit to points

 

[Deleted member 26818]

Why do you need to run fire cables in a separate compartment?

 

[Ian1981]

Jobs that I’m on in commercial settings almost 100% of the time the spec insists on fire alarm cables being kept away from other building cables using appropriate segregation, and I’m not 100% sure but does bs 5839 -1 not recommend this?

 

[benji]

Just re-read question so could be in trunking or could be clipped direct to building fabric or on separate basket or tray its a bit open-ended

 

[apprentice123]

sorry there is drawing that go along with this that show that the trunking will be fixed directly to a block wall along the length of its run, all cables will leave the trunking in galv conduit out of the bottom of the trunking meaning that i would need to cross cables across each other at different points along the length of the trunking. meaning i would need a way of crossing said cables without mixing band 1 and band 2 cables.

 

[Toneyz]

If you can post a copy of the drawing and exact question you may get a more precise answer.

 

[elsparko]

why not just have a seperate containment for the cat 5/singles/FP

you could then make brackets to hold trunking, any conduit drops you could make offsets to reach the wall and drop as normal

that way you avoid crossing cables at drops

 

[Rocboni]

You can notch the internal seperator to allow for a piece of 20mm plastic conduit, this allows the cat 5 to pass through the 230v compartment and vice versa, then you just bush onto the the trunking as normal.

 

[benji]

If you went down the 3 comp.truking route you could drill drill say 20mm hole in the bottom of trunking then continue drilling in the same line through to the next compartment ect. sending conduits through to the respective compartments,but it would compromise trunking capacity.What about bending radius of cables?

 

[Simonslimline]

Why would they need to cross each other?

The trunking will have a divider in it which separates the two voltage bands. Drill out the bottom of the trunking where you need the cables to exit and tube from there on to final position. Or am I missing something ?

 

[elsparko]

Why would they need to cross each other?

The trunking will have a divider in it which separates the two voltage bands. Drill out the bottom of the trunking where you need the cables to exit and tube from there on to final position. Or am I missing something ?

would it not be bad practice to do so though? ive never seen data cables in the same containment as 230v

usually kept very very seperate

 

[Simonslimline]

would it not be bad practice to do so though? ive never seen data cables in the same containment as 230v

usually kept very very seperate

On all the jobs i work on the data has its own basket so not something i have had to think about personally.

528.1 (iii)?

 

[elsparko]

On all the jobs i work on the data has its own basket so not something i have had to think about personally.

528.1 (iii)?

dado trunking must have the sort of set up with dividers so must be allowable, just seems "wrong" to have data cable in the same trunking as 230v

usually on bigger jobs the data/fire protection is subbied out so never had to worry about it either really lol

 

[Simonslimline]

dado trunking must have the sort of set up with dividers so must be allowable, just seems "wrong" to have data cable in the same trunking as 230v

usually on bigger jobs the data/fire protection is subbied out so never had to worry about it either really lol

Metallic trunking is available with divider also.


Same here, except we install all the containment for the data, fire and bms also.

 

[elsparko]

Same here, except we install all the containment for the data, fire and bms also.

the data guys installed their own tray on the roof beams at both factories i rewired, our traywork was on the floor and they basically mirrored our routes on the ceiling, there were places the cat5/230v met in the same containment with data sockets next to 230v sockets for servers/computers

as long as every possible effort it made to avoid interference it seems "good practice" but possibly not enforceable by regulations

the existing data cables were wrapped around 3 phase and their routes were as the crow flies across the loft floor

was glad to get to the end of that job, shame the factory insisted on keeping all the scrap

 

[Deleted member 26818]

It’s very common for data and 230V to be used in dado trunking.
Not so common for data and 230V to be used in the same metal trunking, ‘T’ pieces are quite convoluted.
Have seen data and 230V on both basket and tray, both with and without dividers.
Never quite understood why 230V alarm cables are kept away from 230V power and lighting cables.
Not aware of any requirement in BS7671 for them to be segregated.

 

[Rocboni]

Cables can be in the same containment as long as they are insulated to the highest voltage present.

Compartment trunking saves installing two lots of containment, we used it in a warehouse which had lots of offices, data cables were in the top compartment, and where they dropped to computers and lengths of dado trunking, 20mm conduit was used to bridge the 230v section.

 

[Deleted member 26818]

Never worried about data bridging 230V.

 

[Rocboni]

Where they cross it should be a 90degrees preferably

 

[Spunkywads26]

It may have been an old wives tale, but I seem to recall that as long as they cross at 90 degrees and do not run along side each other for more than a metre they should be fine.

*Tin hat firmly secured*