PME help please

[panicoll]

Hi just looked through bs7671 543.4 PEN is this the same as pme?

 

[Ponty Massive]

A PEN (Protective Earthed Neutral) conductor / cable supply is a single core SWA terminated with the single core conductor as the phase and the armouring used to supply the neutral and combiened earth terminated as a PME supply.

Hope this makes sense??

Ponty

 

[Pinto Baz]

No, but there is a connection, PME refers to the fact that the system of supply has multiple earth points (protective multiple earthing) this is to keep the cable at earth potential by regularly connecting it to the actual mass of earth (by earth rods) along it's length. (with length you get resisance and, as the neutral wire carries a current, current through resistance = voltage (IxR=V)) In this case the conductor that is being regularly earthed does happen to be a PEN as it is the neutral that is also being used as the earth return path (PEN = Protective Earthed Neutral) once the PEN arrives at the installation origin (service cut out, Main fuse) it is split into seperate neutral and earth wires

 

[Pinto Baz]

P.S Now it seems to be popular to talk about the PME System. I know it as the TN-C-S system. The two are one and the same. 'C'ombined earth neutral in the supplier part of the system. 'Seperate earth and neutral in the installation (i.e. the house)

 

[panicoll]

The supply is a single core and arrmor is all copper and is twisted together then splits at cut out and is marked pme at db. Problem is they have use split con swa from cut to db. And doubled up another db off mains switch. Now I need to add
Another 2w db but I need to either take swa out the db and some
How spilt it and use double insulated

 

[panicoll]

So pen is the conductor combined earth and neutral. And pme is the system ?