Is there any reason a circuit fed in t&e, protected by an RCBO, can not be clipped to a accessible surface feeding a socket
In general, no, nothing prohibits surface clipped twin with earth to a socket outlet or for some other purpose.
There might be a prohibition under certain circumstances, for example if the cable exposed to undue risk of damage.
There might also be a CONTRACTUAL prohibition, if for example the client or the consultant or architect says “no surface wiring” or even “no twin with earth” then this instruction must be respected.
clipped to a accessible surface would mean mechanical damage protection required to some degree whether by touch or impact but apart from that then usually it1s aesthetics which might be your next consideration.
There is no blanket ban so far as the regs is concerned but company policy or staff hierarchy might be involved here
AJJewsbury:
Conventional plastic clips probably wouldn't be acceptable these days - the regs require all cable supports to be fire resisting.
- Andy.
Do they ? I thought that the new requirement was to “prevent premature collapse in case of fire” A short vertical run up or down the wall to a socket outlet would seem to be self supporting if the plastic clips melted. A horizontal run along the wall likewise, it would remain close to the wall after failure of the fixings.
If the cable ran overhead which sounds unlikely, then yes sufficient of the fixings need to be fire resistant so as to prevent premature collapse.
broadgage:
AJJewsbury:
Conventional plastic clips probably wouldn't be acceptable these days - the regs require all cable supports to be fire resisting.
- Andy.
Do they ? I thought that the new requirement was to “prevent premature collapse in case of fire” A short vertical run up or down the wall to a socket outlet would seem to be self supporting if the plastic clips melted. A horizontal run along the wall likewise, it would remain close to the wall after failure of the fixings.
If the cable ran overhead which sounds unlikely, then yes sufficient of the fixings need to be fire resistant so as to prevent premature collapse.
I did say ‘probably’ - if there were something else that would support the cable if the clips failed then yes the requirement could be met in that way. The OP didn't mention the run being short though, and the requirement only applying to overhead or escape routes disappeared some time ago. Even relatively short runs would likely need additional support if it turned an internal corner or changed from vertical to horizontal. Collapsing but still remaining close to the wall, may well keep it out of escape routes, but wouldn't meet the current requirements to my mind.
- Andy.
tonydon:
Is there any reason a circuit fed in t&e, protected by an RCBO, can not be clipped to a accessible surface feeding a socket
T&E cable has been surface mounted on walls for about 75 years covered by an OCPD. RCBOs and RCDs are relatively new.
We often now clip T&E inside garden sheds and if done correctly can look reasonably neat.
Remember, T&E cable doesn't cope too well with axe wielding fruit cases throwing wobblies because somebody's nicked their prize carrots but then very few other cable systems can withstand that level of madness.
So generally not suitable without protection when used for industrial purposes.
Legh
doesn't cope too well with axe wielding fruit cases throwing wobblies
If you do need to design for that situation, consider steel conduit, also OK on a surface,
but for the OP yes it is perfectly OK to have T and E or even flex suitably clipped. As others have said ‘other factors’.
The nice thing about clipped direct is that as the route is not concealed, there is no need to follow lines of least surprise, so you can have cable routes that say ‘hello mother’ in arabic script if you wish.
Mike
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