0.02mo.

=20kΩ - so that makes it a simple answer then!

   - Andy.

Andy may be tongue in cheek. I took that to be 20 mΩ or 0.02 Ω.

Looks like the meter is set to Mega Ohms, 500 V. Reading of 0.02 M ohms 

If a current value of 30 mA is used in the equation , an item would not be considered an extraneous-conductive-part if the resistance (Rcp) is at least 7.67 kΩ ( 0.00767MΩ)

Ah yes, I need to go to Specsavers. 

I do have a concern about people considering "sheathed" ("insulated", or "plastic covered") metal parts that are buried in the ground, but later become connected to accessible metalwork in buildings, as not 'extraneous-conductive-parts'. Stones in the ground, and, depending on the plastic covering, water ingress, can render the metallic parts as 'effectively earthed' ... but this is not measurable during original 'erection' of the installation.

I do also have concerns about the fact that main protective bonding is now only applied to buildings ... but not other installations (this has been the case for quite some time). It will cause more of a problem for installations such as water treatment, chemical processing/manufacturing plants (with outdoor installations) etc.

I fully understand the issue regarding "how big a site are we talking about" vs "touch and step potentials" .. but if "rules" can be applied for HV, they can also be adopted for LV.

I do have a concern about people considering "sheathed" ("insulated", or "plastic covered") metal parts that are buried in the ground, but later become connected to accessible metalwork in buildings, as not 'extraneous-conductive-parts'.

Agreed - and to add, that if the same part emerges into another building (or otherwise into another electrical installation) even if it's perfectly isolated from the general mass of the earth - then it's still likely to be an extraneous-conductive-part as faults in the other installation will may impose a potential onto the part (and hence into our installation) - via c.p.c.s to valaves/pumps etc even if the pipe isn't bonded.

In the OPs case everything seem to point to it being extraneous.

   - Andy.

If a current value of 30 mA is used in the equation

I think that would be an unusual choice by the designer - an installation where users could get noticeable shocks between parts (even if it's not quite enough to kill them, well 95% of them at least) wouldn't be considered satisfactory by most members of the public. I would have thought that most would have picked a much lower value - typically yielding required resistances between 23kΩ and half a MΩ.

   - Andy.

Indeed - 20-30 Kohms, reflecting 10mA or less into a full mains fault condition would be a more appropriate upper limit (*).  of course Full voltage fault conditions are rare in any one property but as more are connected in parallel, as happens is a system like this, the chances of something nasty happening in one or other increase the odds.

Mike

* And that sort of resistance is the kind of thing you can see from almost casual contact with ground such as the painted 'skids' of containers, or wet and mud caked tyres on farm trailers.

Even a toy tent peg manages a few k ohm or two.

So what happens if somebody connects to the pipe in another building?  There's every chance that it could then become earthy in your building, because of what it's connected to in the other.