Years ago I had huge problems with volt drop on a caravan site and radios had mains hum and when transmitting likely I was in breach of licence conditions. But today the switch mode power supply has completely changed the situation with items like lap tops running anywhere between 100 - 250 volts and other items also have a huge voltage latitude typical LED GU10 lamp will run 180 - 250 volt for example.
The power requirement is now 5% with lighting at 3% and when we do an Electrical Installation Condition Report (EICR) I suppose we should check the volt drop.
With this in mind I made a Java Script page http://gw7mgw.co.nf/Electric-Cal5.html to test the volt drop. But when I started to do tests I found the standard loop impedance tester who's results are used to calculate the results were to put it mildly were just not accurate enough to be sure an installation was non compliant until it reached nearly double the permitted volt drop.
Once I started to see the problems I had to question is it really worth working it all out? OK when wildly out of spec the yes but with a volt drop of 23 volt which is double the permitted is it really worth correcting? And could one really put it as unsatisfactory on an EICR?