Competition time... Lowest TT Zdb
- Thread starter Adam_151
- Start date
It's obviously going to be low so I'll take a stab at just under 15ohms with parallel earth paths helping matters somewhat!
That's a bit unfair without giving us some more information. If the earthing system was connecting to structural steel then that could help matters significantly. I'll start the bidding at 1.2 Ohms.
0.8Ω
None of you are too far off.... 1.41 ohm (except perhaps gary!)
Reckon RF must have seen lower
Go on then, how come it was so low?
Probably because TN-C-S involves a bit more for the DNO than simply linking N+E at the cutout. There must also be DNO earth electrodes at various points throughout the distribution network (hence Protective Multiple Earthing), and out in the sticks where TT is commonly encountered, this would be difficult to achieve.
TN-C-S can be dangerous in some situations as a potential can exist between true earth (ie the ground out side) and the installation earthing system.
Oh and what he said above^^ too.
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