gas meter earthing

[timbim]

It can also drop appreciably below that.

And through potentially fairly cold places.

But you design for the worst case, not the best case.

 

[JohnW2]

Also 10mm bonding cable is restricted to about 27 mts for MET to gas meter, bigger distance need bigger cable.

Although I can't currently find it in either regs or OSG, I'm sure I've read that the maximum permissible resistance is 50mΩ (i.e. 0.05&#937, but with 10mm² cable having a resistance of about 2.2mΩ per metre, that would imply a maximum of about 22.7m. can you tell me where your 27m figure come from? Thanks.

Look up the meaning of 'about' Is 27.32 mts accurate enough?

I suspect you didn't read what I wrote very carefully, because I was not criticising the precision of your "about 27 mts" (any more than I would criticise the "about 22.7m" in my response) - I was talking about the difference between "about 27 mts" and 22.7 metres. The tone of your response is such that I presume you thought I had typed something other than "22.7".

However, although you do not appear to have realised this, BAS did - and explained that the reason for the difference was that you were quoting a figure for 20 degrees C, which was a helpful answer to my question.

Kind Regards, John.

 

[JohnW2]

Even in the UK the ambient temperature can rise appreciably above that,

It can also drop appreciably below that.

Very true, but totally irrelevant. I would hope that you don't need me to tell you that you have to choose the cable size to be compliant at the highest envisaged ambient temperature. If you don't understand the concept of designing for 'worst cases', then I fear for anyone's electrical installation you get near!

Kind Regards, John.