from the permited cable routes section in the OSG 7.3.2 (16th edition) a safe zone is created horizontally from the acessory, is does not have a limit on the length of this safe zone.

does this mean it is accepted that this zone is unlimited in length??

seems a bit stupid to me that it can be unlimited, does this zone include going around corners that are 90 degress (as it appears in the on site guide) such as in a conservertory?

wozzy wrote on Dec 20^th, 2008, 8:20pm:



NO - The zones do not go around corners.

In conservatories in the past I have placed a socket on each wall for this very purpose.

I think the thing with prescribed zones is that if you run cables within 150mm of ceiling / corners, its not often that anything will be fitted to these areas that requires drilling (except kitchen corner units).  With runs to an accessory, people should check which way the cable is running, as regards horizontal runs, you can't run horizontally through every room in the house to an outlet at the very back of the house without offering additional mechanical protection unless there is an outlet in each room to show that there could be a cable running horizontally to it.

I would only use them in exceptional circumstances, and even then only if there really was no other way.

Things fixed in corners?  Coat racks close to the wall, speakers in the corner of a room, corner shelf's for plants, curtain tracks etc.

The NIC did an article on the top 150mm rule.  They had some statistics which commented on plasters fitting coving and using nails to support the coving while the adhesive goes off.  You see this regularly.

only time i use the safe zone at the top is conservatories with a light pendant type fitting

straight up from switch - up angle of roof behind plasterboard - along roof pitch behind pvc

and thats rarely as most go for wall lights or switched lamp sockets

wozzy wrote on Jan 17^th, 2009, 5:35pm:



MICC and Armour dont need rcd protection whether they are surface or buried at what ever depth, but that depends on what circuits they are supplying and in which type of installation (domestic, commercial, industrial), i.e sockets being used by unskilled persons rated less than 16a for general use or for use outside by portable equipment etc... Also for circuits supplying current using equipment in a bath or shower room (probably wouldnt see that so much), a cooker circuit with a socket incorporated within it etc.. and/or if the installation is TT.

Normal T&E cable needs rcd protection if buried less than 50mm, but doesnt if buried more than 50mm or mechanically protected by earthed metallic covering, again thats dependent on what circuit its supplying and if TT.

Split Concentric cables cant be used as they are treated the same as T&E, for what reasons i dont know, i remember lec mentioning it on another post back along.

Armour, MICC or t&e incorporated within an earthed metallic covering would be good for installation outside of prescribed cable zones.

Split Concentric cables CAN NOT be used out of a safe zone - Thats why I say treat it as T+E!

wozzy wrote on Jan 18^th, 2009, 10:54am:



Your link is to a very old edition of the "Connections" magazine, which was written in the times of the 16th edition