"Start at the very beginning,
Connect a recorder to the main incomer to determine a flicker problem in a sub-let flat. Connect a voltage recorder to a mains supply to see why the earth leakage circuit breaker trips. Connect a recorder to a distribution board feeding the input of a UPS to see why the UPS output fails.
It appears illogical, yet this is exactly what people do and actually expect to see meaningful results.
Ensuring the equipment is placed at the correct location, i.e. where it will "see" the fault, is rather important. It may appear to be a "common sense" statement - but the problem is common sense is not that common! A long road still exists in teaching people to use the correct methods. My rule is simple:
Go to Point Of Problem
It is the only way to tackle any electrical issue. Testing at the "main incomer" has often proved to not show the fault at all, other than the supply is "sound". This can so easily miss the next common failing point being the main breakers or fuses. By testing at the POP the whole installation is tested, including the main supply, breakers, and everything in between.
Not testing at the POP is a major failing of electricity suppliers through two reasons. The first is the reluctance of the investigator to delve in to any possible cause of the problem. His main concern is to prove to his employer that they (the electricity supplier) are not at fault. Beyond that their responsibilities cease.
This leads to the second reason being that the investigators are actually commanded by their employers to not test beyond their point of responsibility. They are literally told to keep their fingers out of clients' power boards etc. I have personally been involved in many cases where the fault lay in some sub-distribution board and was only found because I test further down the line.
Then you get those who refuse to connect live, and will find the first convenient place where the power can be shut down so as to connect a recorder. And, this will never be the output of a UPS. Now, when investigating the reason a data centre is failing, connecting to the input of a UPS is about as close to useless as one can get!
'Sparkies' too have been found to conform to a new way of working being "I don't have time to do the job properly the first time, but can find time to come back and do it properly later". If you only knew how many flicker complaints go away when they install voltage recorders because they often find loose connections when installing them!
And was he not lucky because a "voltage recorder" is the wrong kit for a flicker complaint! All such recorders might do (there is no guarantee) is confirm there is flicker. They bring you no closer to the level of flicker or what is causing it.
Testing at the Point Of Problem is the first part of a successful measurement, the second part is planning what to use. We cover that now.
© 12.07.04 / 10.05.05