For those who want to learn more about 'discrimination' in terms of providing an electrical protection study, read on (or click on the .PPT document attachment):
What is ‘discrimination’? Discrimination is crucial in ensuring that only the protection device immediately upstream of a fault will trip, so that the remainder of the electricity supply still works – so those lights will stay lit.
Fitting the different points in the electricity supply chain in an electrical installation with circuit protection devices that have adjustable tripping characteristics, the discrimination can be such that the disruption caused by a fault is minimised.
For anybody carrying out a proper electrical protection study, it is the manufacturers, in most cases, who will need to be approached first, as they can provide the required discrimination tables and other relevant data on their circuit protection devices and related equipment.
For more information on this topic, provided in a fully illustrated and very concise PowerPoint presentation, click on ‘Discrimination of protection devices on installations’ (be warned that it is 1.24 MB file size).