Mechanical Protection

[fattony]

I been told that where cables are installed below 2.5m mechanical protection is required unless the cable is MICC or SWA, is this true? What requlation is it?

 

[JohnD]

2.5m below ground level in a trench? Or less than 2.5m above ground level on a ceiling? or wall? or hung in the air?

 

[Spark123]

Might be of some use;
//www.diynot.com/forums/viewtopic.php?t=57651

 

[fattony]

2.5m above ground, sorry wasn't very clear. Basically cables clipped direct must have mechanical protection if they are below 2.5m.

 

[sootys68]

ALL CABLES IN CIELING OR WALL MUST BE AT MINMUM OF 50 MM IN DEPTH , OR MUST HAVE AN EARTHED MECHANICAL PROTECTION , I.E EARTHED STEEL CONDUITEVEN CABLES CLIPPED DIRECT SAY IN A LOFT 50 MM FROM THE BOTTOM OF THE CIELING JOIST
________________________________
lynda, moderator

please note forum rule 6

 

[Spark123]

 

[fattony]

Ok, think commercial, offices or store rooms. For Example emergency lighting wired in FP200 clipped direct on celcon block. The cables come down to a test switch (1200mm) are we saying this drop should have mechanical protection? If the cable was clipped around the room on the celcon block at a height of 2m, should it have mechanical protection whereas if I clipped it at 3m no mechanical protection is required.

 

[RF Lighting]

But is FP200 not the same as MICC, in so far as you would have to penetrate the earthed screen, before you could come into contact with the live, thus blowing the fuse?

 

[sparky40]

Are we not using the 'zones' allowed then ? Why make such a hard job of things why we have them ( zones I mean ) ? 50 mm ? Do you chase for your capping too ?

 

[sparky40]

Mis-read the post . Stella again ! Once again , sorry.

 

[Pensdown]

I been told that where cables are installed below 2.5m mechanical protection is required unless the cable is MICC or SWA, is this true? What requlation is it?

The outer sheath on T&E provides MP, all be it limited. The outer sheath on FP200 provides MP, a bit more than T&E. The armour and sheath on SWA provides MP, and steel conduit provides very good MP. It's up to you as the designer to selected the correct cable for it's environment.

 

[ban-all-sheds]

ALL CABLES IN CIELING OR WALL MUST BE AT MINMUM OF 50 MM IN DEPTH , OR MUST HAVE AN EARTHED MECHANICAL PROTECTION

1) That's not accurate.

2) What does it have to do with the original question?

 

[plugwash]

getting back to the original question i don't belive there are any general rules requiring protection of cables clipped to a wall but there is the general catchall that equipment must be suitable for its environment.

i don't think most sparkies would be happy seeing unprotected T&E in accessible places in a workshop or similar environment. there is just too much risk of damage if tools slip etc.

note that while high impact pvc conduit will not stop determined use of a drill its very good protection for surface wiring in rough environments.

 

[RMS]

The only regs that i think has relevance to the original post is 522- selection and erection in relation to external influences.

 

[Job_n_knock]

If you ever feel the inclination, try and hammer a nail into a wall where you know there is steel conduit, it goes in surprisingly easily.
Referring to the original question, surely common sense would prevail. No spark worth his salt would install anything that potentially could be damaged. If I was working in a workshop Id use trunking at high level and drop down with tube for example. Id never use T&E.
As for Fire alarms and Emergency lighting I do use FP200 or Firetuff but only because its specified these days. As an old hand I used to get a great deal of satisfaction from using PYRO. A few years ago (lot more actually) who remembers the site in London that went up in smoke, all the container site huts stacked on top of each other were burned to the ground and the fire alarm was still ringing although it was a mangled mess. I should stop now before I digress too far.