Davethsparky
Well-known member
I thought 21 was a stated figure from the DNO , at their transformer, and then, as you say, over 200 is said to become unstable .
Nope, there is a minor note in the regulations which suggests that values above 200 may not be stable, nothing to do with 'what is said to become unstable'. It's not any form of recommended or maximum value just a very annoying note which a lot of people seem to take as a target value