- Reaction score
- 2,602
And, to answer the original question, for an installation protected by a 30mA RCD, I'd accept a Zs of 200 ohms on an EICR without any additional comment.
For a new rod, then I'd attempt to comply with the "as low as practicable" note (there's a subjective requirement if ever I saw one!).
Incidentally, I note that Ra includes the resistance of the earthing conductor and the final circuit cpc up to the exposed conductive parts.
In 411.5.3 the regs seem in some confusion between Ra, Zs and "the resistance of the earth electrode", which are, of course all different (although in most cases, not by much).
(Should be subscript 'A'; how do you do subscript?)
For a new rod, then I'd attempt to comply with the "as low as practicable" note (there's a subjective requirement if ever I saw one!).
Incidentally, I note that Ra includes the resistance of the earthing conductor and the final circuit cpc up to the exposed conductive parts.
In 411.5.3 the regs seem in some confusion between Ra, Zs and "the resistance of the earth electrode", which are, of course all different (although in most cases, not by much).
(Should be subscript 'A'; how do you do subscript?)