Can someone reference the reg for testing an extraneous-conductive-part, in the examples given by 411.3.1.2. I only ask that, you would not need to test (those examples), as the reg says they have to be bonded, end of?
There’s no Reg stating you have to test whether something is an extraneous conductive-Part.
There’s no need for one.
If it’s extraneous (i.e. comes into the building from outside), is conductive (i.e. can conduct electricity) and likely to introduce a difference in potential, then it needs bonding.
Determining whether something is extraneous is relatively easy, in the majority of instances you don’t even need to look, you just know.
Gas, water, electricity, cable TV, satalite TV, waste water, telephone, oil, etc. they’re all extraneous.
Determining whether something is a conductive-part however, seems to be problematic.
Plastic coated telephone cables, satellite and cable TV cables along with plastic waste pipes are all deemed as non-conductive.
For some reason, there’s confusion as to whether plastic gas pipes, plastic water pipes and plastic coated oil lines are conductive.
Because of this confusion, a lot of people are advising we test these supplies to determine whether there’s any connection to Earth.
Unfortunately there seems to be various views on what resistances indicate either a reliable connection to Earth or no connection to Earth.
Some say 0.05 Ohms, others say 20 Ohms indicate a reliable connection to Earth.
For whether there’s no connection to Earth the figures for resistance are 23 Mohms or 7.67 Kohms (22 Mohms and 6.67 Kohms when the 1 Mohm resistance of the human body is taken into account).
