multimeter

[andywtks]

hi

posted this earlier - it disappeared for some reason

watched an electrician working in my house yesterday - when he used his multimeter to test some new sockets, it read 240v between live and neutral and 240v between live and earth, but 0v between neutral and earth

didn't get a chance to ask him at the time ... but i'm just curious what those readings mean

can anyone explain?

 

[kevplumb]

cos the neutral is earthed at the sub station

and thats a thick plumber

 

[andy]

hi

posted this earlier - it disappeared for some reason

watched an electrician working in my house yesterday - when he used his multimeter to test some new sockets, it read 240v between live and neutral and 240v between live and earth, but 0v between neutral and earth

didn't get a chance to ask him at the time ... but i'm just curious what those readings mean

can anyone explain?

there are 2 wires that carry the power. live and neutral. the neutral is earthed at the substation and at points along its journey, since earth is neutral, there is no voltage between them

 

[breezer]

The neutral is only earthed at the "star point"

if it was earthed at "points along the way" it would be a PME supply

 

[andy]

The neutral is only earthed at the "star point"

if it was earthed at "points along the way" it would be a PME supply

by points along the way i was meaning PME.

 

[securespark]

he says, quickly.

 

[plugwash]

PME/TN-C-S seems the recs preffered method nowadays

i personally belive its a corner cutting sham

i also think its hugely hypocritical that they allow CNE cores in supply systems but not within an install.

 

[Big_Spark]

PME/TN-C-S seems the recs preffered method nowadays

i personally belive its a corner cutting sham

i also think its hugely hypocritical that they allow CNE cores in supply systems but not within an install.

Plug, are you having a "Blond Moment"?

Corner cutting sham? How on Earth do you work that out, it costs more to install a TNC-S system from scratch than any other. The cheapest used to IT (Banned for a long time now) then it is TT.

Further, the reason for allowing Concentric cables in supplies and NOT installations is purely a matter of safety. In the ground it is expected that the cable will be a Concentric of some desription, but this is certainly NOT the case inside an installation, and the dangers of (no disrespect to all here) DIYer's pi55ing about with concentric cables are huge. I have personal experience of a DIYer who used some concentric cable he had "obtained" to connect up the granny pad he built at the bottom of his garden, Killed his Mother, a dog, and badly burnt himself and will have brain damage for life, not to mention the horrendous scars, mentally and physically.

 

[plugwash]

PME/TN-C-S seems the recs preffered method nowadays

i personally belive its a corner cutting sham

i also think its hugely hypocritical that they allow CNE cores in supply systems but not within an install.

Plug, are you having a "Blond Moment"?

Corner cutting sham? How on Earth do you work that out, it costs more to install a TNC-S system from scratch than any other. The cheapest used to IT (Banned for a long time now) then it is TT.

I was comparing to TN-S (which seemed to be the preffered system at least for underground supplies before TN-C-S became popular)

if PME/TN-C-S isn't cheaper than TN-S then why do the recs use it?

Further, the reason for allowing Concentric cables in supplies and NOT installations is purely a matter of safety. In the ground it is expected that the cable will be a Concentric of some desription, but this is certainly NOT the case inside an installation, and the dangers of (no disrespect to all here) DIYer's pi55ing about with concentric cables are huge. I have personal experience of a DIYer who used some concentric cable he had "obtained" to connect up the granny pad he built at the bottom of his garden, Killed his Mother, a dog, and badly burnt himself and will have brain damage for life, not to mention the horrendous scars, mentally and physically.

nasty.

how exactly did he **** it up?

i have heared of some pretty nasty incidents caused by faults with rec TN-C-S wiring

trouble with TN-C-S is that if the neutral fails the operating current flows down bonding conductors and the objects they bond too

i heared a story from one of the guys on ATT about a rec pole with a lost neutral and a group of flats

both flats were pme

the only connection between thierr earthing systems was some suplementry bonding

one flat lost its neutral

this totally fried a lighting cuircuit cable that was in the path to the suplementry bonding.