[werk_ag]

It's very interesting that your 1.2 metres of twisted pair is working well. Maybe in the future, once everything is working well, it will be worth experimenting to see what is the maximum length that can safely be used.

Yes, it is. I was also surprised.
I'm using this SHT21 module:



If you look at the module schematic you will see that they are using some MOSFet transistors on the SDA / SCL lines, maybe this explains why it's working with SDA/SCL lines with 1.2 meters length.

This one:
http://www.ebay.com/itm/1pc-New-Standard...3cdfc85ac2
costs three times less and it seems to have the same schematic.

...I am very happy to be told something that I already know, but what I don't like is making a mistake and then somebody saying to me "but I thought you would know that"

Can't agree more.