Routing of meter tails

[leep82]

hi all any advice on the following scenario much appreciated. I have taken on a rewire from another electrician whos personal circumstances mean he cant finish the project. Majority of the first fix has been completed including the repositioning of the DB. The original DB was situated inside the kitchen base units adjacent to the meter and cut out. I can see why the DB is being moved as it isnt the most accesible of places and a new utility room is being created which is much more suitable. However it is the routing of the new ‘ tails’ that im not 100% comfortable with.

25mm double insulated tails along with a 16mm CPC have been run at low level behind the new kitchen base units before rising up in a PVC trunking to ceiling height. They then run approximately 8mtrs through the joist before again dropping down in a PVC trunking to what will be the new DB position. At no point are they buried in a wall. Personally i would have used 16mm2
T&E but the ceiling is now boarded and skimmed so the customer and builder is very reluctant to drop the ceiling and allow me to do this. The intention is to provide our own overcorrect protection at the origin so as not to be solely relying on the 100a DNO fuse.

Ive searched varies threads looking for an answer or advice so apologies if this has been done to death. Can anyone point me in the right direction of where to look in the regs or offer any other advice

 

[leep82]

You’ve missed the point, it is not about striking the cpc, it is about making contact with earthed metal first.
Yes there might be slightly more chance of hitting the cpc, but that’s no good if the metal object has gone through the live first and injured or killed the person holding it.

‘More chance’ doesn’t offer any protection at all.

I dont think ive missed the point to be honest i fully get that. But neither the T&E method or insulated/sheathed tails offer any earthed metal work.

 

[DPG]

Exactly, and that is the whole point. Neither offer any more protection.

 

[DaveHsussex]

Problem: Reliant on Overcurrent for protection against damage to tails, damage could present an electric shock risk inside the house if there is damp etc. In fact, a high ohms fault to the tails might not trip the cutout...ever, but it will make a wall or floor live if it's damp and kill someone.

Tails are not recommended to be more than 3m. Once you put an isolator inline, you're solving that.

I'd put a 100ma time delayed isolator/rcbo just after the cutout, you probably won't get perfect discrimination when rcd testing though, although some meters play nice.

And if you had a choice, it should of been XPLE25mm to cover all bases and future proofing to 100a fuse upgrade when they want a car charger putting in the garage for their diet tesla in 5x years.