Back in my days at college I was always taught that RCD's or ELCB's as they were then should be treated and used as secondary forms of protection and not as a substitute for proper circuit design
How many people (customers) actually follow the instructions to press the test button every 3 months to check the RCD functions, over the years I have come across many RCD's that are stuck and don't trip when the test button is pressed or a tester is used so how much reliance can you put on it operating when required. May be there is a market for an RCD with a timer built in to warn it needs testing every 3 months
We all know that a fuse is a single use device but we have no idea how many times an MCB or RCD has been tripped by faults and how it's reliability and calibration has been affected by this and other factors like ageing (springs weakening etc)
Statistics are used a lot but there is no way to collect data on the number of lives that have been saved due to RCD's as an RCD tripping is never reported but you never hear of any stats or incidents where RCD's have failed to operate causing a fatality or serious injury a few have already admitted on here that they avoided serious injury due to RCD's and I think if most of us are honest we all have had similar experiences and will never know whether the overcurrent device would have cleared quick enough to save us
How many people (customers) actually follow the instructions to press the test button every 3 months to check the RCD functions, over the years I have come across many RCD's that are stuck and don't trip when the test button is pressed or a tester is used so how much reliance can you put on it operating when required. May be there is a market for an RCD with a timer built in to warn it needs testing every 3 months
We all know that a fuse is a single use device but we have no idea how many times an MCB or RCD has been tripped by faults and how it's reliability and calibration has been affected by this and other factors like ageing (springs weakening etc)
Statistics are used a lot but there is no way to collect data on the number of lives that have been saved due to RCD's as an RCD tripping is never reported but you never hear of any stats or incidents where RCD's have failed to operate causing a fatality or serious injury a few have already admitted on here that they avoided serious injury due to RCD's and I think if most of us are honest we all have had similar experiences and will never know whether the overcurrent device would have cleared quick enough to save us