Cable Fixings

[mcelec]

Morning,

 

I'm out of the office so dont have a copy of the regs with me, I have a site meeting I'm about to go in to and they want to discuss the fixings of cables, as we have flagged up that a sysystem that we are commissioning is non compliant as the cables are fixed every 2 metres.

 

So I need the BS number and reference ideally and the recommended spacings, of the top of my head 300mm horizontal and 400mm vertical

normally we space metal ties out further (around every 900mm) and use plastic between, I can't recall what the standards say about this?

 

Any help greatly appreciated.

 

[mcelec]

BS5839 talks about adequate support, so the question is, in a closed ceiling space with no access is fixings at 500mm intervals with every second fixing being fire rated adequate, personally I think possibly so.

 

BS7671 on site guide table 4A provides spacing, however this talks about cables in accessible positions, so if the cables are not accessible and unlikely to be disturbed then it is arguable that these minimum fixing spacings are not relevant?

 

I'm looking for some input please.

[AdrianMealing]

What about the new requirements for containment of cables in escape routes, does this come into play in your current situation? if it does then whether its accessible or not is irelevant i would think.

[MrHappy]

exit routes need metal fixings, IIRC the spacings ain't stated ?

5839 states spacings but your meant to fit as stated by the manufacture.

Ventcroft say metal fixing-

V 300mm

H 400mm

Tray 1500mm (I take "tray" to be supported inside a Horizontal a tray/ basket not vertical or under / outside)

[AdrianMealing]

exit routes need metal fixings, IIRC the spacings ain't stated ?

5839 states spacings but your meant to fit as stated by the manufacture.

Ventcroft say metal fixing-

V 300mm

H 400mm

Tray 1500mm (I take "tray" to be supported inside a Horizontal a tray/ basket not vertical or under / outside)

I was pretty sure the reg said escape routes and not exit routes. The reasons for this is, i believe, that not all escape routes are marked as an exit, for example a window.

[Rulland]

My NICEIC assessor basically told me'class everywhere as an escape route', reason being firemen etc would need access to every part of a building to retrieve bodies etc, ie, a body could be in the corner of a large room, no doors close, but a safe route would be required in all cases.

[datadiffusion]

I guess you must have seen the Colston fire pics Adrian?

 

Good to see all the cable in wire baskets tbh, but how the hell the fire got out of control like that I can't imagine...

[AdrianMealing]

I guess you must have seen the Colston fire pics Adrian?

 

Good to see all the cable in wire baskets tbh, but how the hell the fire got out of control like that I can't imagine...

I was driving through the centre of town about 40 mins after it started, smoke everywhere

[datadiffusion]

Yeah the pics were incredible - I guess the building was just a preserved facia on a concrete shell because the FB were happy walking around on the 'floor' with half the roof burnt off...

 

Corridors were nothing left and open to the sky, but cables in stainless baskets, mostly cables burnt to nothing by the looks!

[Adi]

Fire resistant cable is not fire resistant unless supported by fire resistant fixings or supported by something fire resistant, ie, caable tray, purlins, brickwork ect...

Clips are as above, every 300mm and this metal saddle on plastic conduit is a load of bollox, it does not hold the cable, ok to stop the cable swiinging aboutt to stop firemen being entangled but not to support the cable to be fire resistant.

As for tthe new rule and containnment on escape routes, this does not apply to fire systems as such, as all fire cable should have been adequatley supported for years now. Nothing new iin the fire alarm world.

...and my keyboard is a cnut, lol