Flat supply wiring and fuse protection.

[rattlehead85]

The earthing system is a TN-S. It is a copper brace strap tagged to the carcass of the ryefield from the head cable sheath.

 

[MDJ]

Oh Okay, readings are good then?

 

[rattlehead85]

Oh Okay, readings are good then?

Yes 0.26 Ze on each phase at the ryefield bars. Psc of 0.9ka and PFC 1.25Ka / 2.5Ka P-P.

 

[MDJ]

sounds good, fair enough then.

 

[rattlehead85]

Thanks for all the advice much appreciated.

 

[SirKit Breaker]

This is where I get my balls busted on this forum, I think the 6mm2 earth wire in the 16mm2 T&E is not adequate regardless of the adiabatic equation, thats if it does actually pass which I doubt,There is a thing as good practice in my view and rollocks to the regs, seriously rollocks to it, I always run a 10mm2 earth wire with a 16mm2 Twin and Earth for the main supply to a flat and usually connect it via a KMF switch via an 80 amp max fuse, a 60 even better if there is minimal load, you get slated on here for suggesting running earths with sub-mains haha, but I have always done it this way and always will.

I dont understand why you should get slated for running additional earth conductors with your submains. nothing wrong with going over the top, belt and braces as we say in yorkshire.
In almost all cases of industrial electrical cabinets i have worked in, have had a nice big juicy separate earthing conductor run into them, so why not flats and houses?

Cheers..........Howard

 

[robsparky1975]

How are the sub mains cables,insulation readings good?,if it were me id do the same as you so a 3,the install is existing and as mentioned by some of the more seasoned sparks "retrospective" so our own preferences to one side,3036 is still recognised obviously as a safe means of circuit protection,i did an old PIR for a firm i used to work for and the boss said dont test anything with a 3036,this was a factory and he couldnt even give a correct explanation as to why!

 

[Guest55]

the only problems with 3036 fuses are that
a. they de-rate the cable capacity by a factor of 0.725
b. they arent great for short circuit protection
c. its difficult to determine the rating of the wire link above 30a.