Explain the health & safety including any configuration issues concerning the calibration of electronic equip?

Sounds like you are working on a report for school? Ok I work in Calibration. Basically as far as I can tell by your question. If an instrument is not proven to be within calibration it could be unsafe to use. For example say you are using a multimeter to adjust a piece of equipment. If that meter is not giving proper readings (calibrated ) Then you could over adjust and blow up the piece of equipment you are working on. Like wise if you use an instrument to test for voltage and do not find any (because the instrument is malfunctioning {not calibrated} ) then you could work on a potentially hazardous voltage and electrocute yourself.