Maximum Disconnection Times

[davesparks]

Is a low earth impedance necessary on TN-C-S and TN-S?

What exactly did you mean when you asked if it's necessary to test the earth rods on TN systems?
I assumed you meant the earth electrodes at the transformer for the N-E link at source and/or the other TNCS electrodes used along the distributing mains.

 

[Cookie]

What exactly did you mean when you asked if it's necessary to test the earth rods on TN systems?
I assumed you meant the earth electrodes at the transformer for the N-E link at source and/or the other TNCS electrodes used along the distributing mains.

Do you have earth rods at the service on a TN-C-S or TN-S system?

 

[davesparks]

Do you have earth rods at the service on a TN-C-S or TN-S system?

No, the regulations dont require this.

 

[Cookie]

No, the regulations dont require this.

Can I ask why? NEC requires that the service has grounding electrodes. So it is a surprise to hear this.