High Earth Readings

[john 1]

Hi Mark here have just started testing and have ran into a small problem. I am testing a TT system and my Ze reading is 85ohms and my Zs reading for my lighting circuit is 27 ohms and my (R1 + R2) is 0.18ohms. My problem is this high earth reading does not comply with the Maximum Zs value for Bs 7671.Just wondering if someone could help.

 

[mark80]

That reading passes aslong as the circuit is RCD protected. Maximum is 200ohms for a TT but people on here normally say to get it to 21ohms if you can.

 

[cbw]

Great readings......what is rhe problem????

Get a copy of the on site guide, will help with figures like this

Is it 1668 the max zs

 

[chiplard]

The 21ohm figure is for the suppliers electrode. The maximum for the earth rod is 1667 ohms but for stability should be no higher than 200 ohms.

 

[cbw]

Whats an ohm between friends!!!