Hi there.
PME and/or TNS install; 16mm tails; 16mm main earth(s); BS1361 Type IIb 100A main fuse.
On a recent EICR i came across this:
Issue Number 1:
There's a mains incomer in the basement that has a 16mm earth run from the PME block on the mains head. There is also a 16mm connected to the mains incomer sheath. The Ze is 0.51ohms at the first consumer unit by the mains head. The Zdb on the top floor is 0.67ohms. PME and/or TNS? I''ve read about distributors leaving sheath connections on when they install PME. Obviously the figure is too high for a PME installation. Should I contact Western Power to get a definite on the means of earthing? That's one issue!
Issue Number 2:
There's a 16mm 6242Y split from the mains tails running up to the top floor of this very large house. The top floor is for 'the kids only' but looks like it used to be a separate dwelling for lodgers. It has its own consumer unit which is fed by the 16mm running up to it from the basement. The only main earth up at the top floor is the 6mm in the 6242Y. I realise from table 54 that PME requires 16mm main earth + 10mm MEBonding, so would I would put this as a Code 2 on the EICR. But doing the adiabatic equation ..... BS1361 main fuse, Zdb of 0.67ohms, measures PSCC of 1.45kA, t=0.2secs ...... I'm getting an S/mm value of 4.53mm. So should it be a Code 3?
Many thanks for any advice.
Hope you all have a good couple of weeks of eating and drinking!
PME and/or TNS install; 16mm tails; 16mm main earth(s); BS1361 Type IIb 100A main fuse.
On a recent EICR i came across this:
Issue Number 1:
There's a mains incomer in the basement that has a 16mm earth run from the PME block on the mains head. There is also a 16mm connected to the mains incomer sheath. The Ze is 0.51ohms at the first consumer unit by the mains head. The Zdb on the top floor is 0.67ohms. PME and/or TNS? I''ve read about distributors leaving sheath connections on when they install PME. Obviously the figure is too high for a PME installation. Should I contact Western Power to get a definite on the means of earthing? That's one issue!
Issue Number 2:
There's a 16mm 6242Y split from the mains tails running up to the top floor of this very large house. The top floor is for 'the kids only' but looks like it used to be a separate dwelling for lodgers. It has its own consumer unit which is fed by the 16mm running up to it from the basement. The only main earth up at the top floor is the 6mm in the 6242Y. I realise from table 54 that PME requires 16mm main earth + 10mm MEBonding, so would I would put this as a Code 2 on the EICR. But doing the adiabatic equation ..... BS1361 main fuse, Zdb of 0.67ohms, measures PSCC of 1.45kA, t=0.2secs ...... I'm getting an S/mm value of 4.53mm. So should it be a Code 3?
Many thanks for any advice.
Hope you all have a good couple of weeks of eating and drinking!