A
andyh
Hi all,
In the middle of a new build and starting to plan the electrics. The outside meter box has already been installed which is a flush unit which protrudes into the cavity wall. The meter has been fitted and connected with an 80A fused switch to allow connection of tails to CU inside. Here is what is proposed:
1. 25mm2 meter tails, from fused switch, run through back of meter box to internal wall. 16mm2 earth cable also run through back of cabinet to internal wall - supply is PME.
2. Meter tails run vertically up internal wall and and across horizontally into kitchen, then dropped vertically again into CU. Earth cable taking same route. Route of tails will be channelled into internal insulated block and then galvanised metal capping on top.
3. Total length of tails from fused switch to CU is 5m.
My query is regarding the small distance from the back of the meter box to the internal wall. From lots of reading it would appear that cables should not be run through a cavity wall. However with an outside meter box and internal CU, you have to run the tails through the cavity, albeit for only a few inches. For this small distance should the tails be in conduit or is it acceptable to run them without? Also should the metal capping be earthed?
As a matter of interest, if cables can no longer be run through cavity walls, how does one supply outside lighting on an exterior wall if you can't route through the cavity?
Thanks for the advice.
Andy
In the middle of a new build and starting to plan the electrics. The outside meter box has already been installed which is a flush unit which protrudes into the cavity wall. The meter has been fitted and connected with an 80A fused switch to allow connection of tails to CU inside. Here is what is proposed:
1. 25mm2 meter tails, from fused switch, run through back of meter box to internal wall. 16mm2 earth cable also run through back of cabinet to internal wall - supply is PME.
2. Meter tails run vertically up internal wall and and across horizontally into kitchen, then dropped vertically again into CU. Earth cable taking same route. Route of tails will be channelled into internal insulated block and then galvanised metal capping on top.
3. Total length of tails from fused switch to CU is 5m.
My query is regarding the small distance from the back of the meter box to the internal wall. From lots of reading it would appear that cables should not be run through a cavity wall. However with an outside meter box and internal CU, you have to run the tails through the cavity, albeit for only a few inches. For this small distance should the tails be in conduit or is it acceptable to run them without? Also should the metal capping be earthed?
As a matter of interest, if cables can no longer be run through cavity walls, how does one supply outside lighting on an exterior wall if you can't route through the cavity?
Thanks for the advice.
Andy
