Hi all, there was an accident in china recently where some workers shorted a high voltage cable by grounding it.
It reminded me that I've never fully understood grounding a circuit from a safety perspective.
I can fully understand why it's a good idea to electrically connect unpowered objects to stop voltages from building up.
It's practical to use the Earth as a general connection for this purpose.
However it makes no sense to me why we would then also connect a high powered device such as a power station to the ground.
This greatly increases the risk of accidents I think.
It's common sense now-a-days to not touch in-use electrical cables. But by Earthing a power station you've effectively connected a neutral cable into every persons foot, so that if they touch a mains live cable, they will get a shock.
Remove the power station's Earth electrode, and a person would have to touch a live cable and a return path cable to get a shock.
In short, why do we use grounding as our standard electrical safety principle instead of isolation ?
I assume its a 'cache 22' situation with each safety principle having its own drawbacks. If so, isolation must have a worse drawback than grounding. What is it?
"For an isolated device, touching a single powered conductor does not cause a severe shock, because there is no path back to the other conductor through the ground." - wikipedia
It reminded me that I've never fully understood grounding a circuit from a safety perspective.
I can fully understand why it's a good idea to electrically connect unpowered objects to stop voltages from building up.
It's practical to use the Earth as a general connection for this purpose.
However it makes no sense to me why we would then also connect a high powered device such as a power station to the ground.
This greatly increases the risk of accidents I think.
It's common sense now-a-days to not touch in-use electrical cables. But by Earthing a power station you've effectively connected a neutral cable into every persons foot, so that if they touch a mains live cable, they will get a shock.
Remove the power station's Earth electrode, and a person would have to touch a live cable and a return path cable to get a shock.
In short, why do we use grounding as our standard electrical safety principle instead of isolation ?
I assume its a 'cache 22' situation with each safety principle having its own drawbacks. If so, isolation must have a worse drawback than grounding. What is it?
"For an isolated device, touching a single powered conductor does not cause a severe shock, because there is no path back to the other conductor through the ground." - wikipedia
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