TN-S earthing

[duncanp]

in a TN-S earthing system, when you have a supply going via armoured cable to a shed attached to house and that shed has a metal pipe which is in contact with earth

This pipe is connected to the armoured connector of the cable - is this sufficient equipotential bonding. Circuit has RCD

Just want to check set up is correct - recently moved in

Now theory questions

Should you have a seperate earth rod? and if you do - would you connect this to the armoured cable and ultimately to the supply earth.

Jason - your statement on earthed tools - does that apply to any external tool with any earth system - or just PME

 

[flyingsparks]

What size is the armoured cable and how many cores? Is the earth going over 10mm or bigger, if so you need to connect this to the metal pipe (is it a service pipe?). Dont worry about the stake..

If its less than 10mm then you need to make it TT. Disconnect the TN-S earth coming over from the house by terminating the armoured into a plastic box or similar, put down the earth stake and connect this to the metal pipe and CPC's.

 

[duncanp]

3 core 2.5mm armoured cable, one core earth plus armour.
4mm G/Y from here to metal pipe.

Should I replace this with 10mm?

 

[Lectrician]

What is the metal pipe?

If it is an extransous conductive part, it would require main equipotential bonding, which would require a 10mm copper conductor back to the MET of the installation. This could be part of the SWA submain, if i was sized correctly.

So, what is the pipe? Is it extraneous?

 

[duncanp]

its part of an old well and pump - no motor now

 

[Lectrician]

Not used? Get rid?

Aint bonding a PITA! You know most folk would not give a damn!