H
holmslaw
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Also the steel conduit is used as the CPC
Nothing wrong with steel conduit/trunking as cpc.
Thanks for the update - but I see that some 'debate' continues!Hi John, I have checked the values, and they all come under the 0.57 ZS values. So this seems to be covered.
Im thinking type C still the best, as patients are often hooked up to drip machines.
This is NOT meant as any criticism of your abilities, but please explain how you are tasked with replacing a distribution board in a hospital yet apparently have no experience of working in such places?Hi guy and gals, Im an electrician that has started in a hospital.
That is true, but it's always worried me a little - since it could be taken as an invocation of a variant of the misconception I've been discussing here over the weekend - in this case that a 10mA RCD/RCBO will result in a lower current flowing through a victim (under leakage conditions) than would a 30mA one.some hospital RCBOs are 10ma, since the risk of shock when you have equipment attached to, or inserted in, your body or its fluids is particularly high.
One might think so, and it may be true on the bench with large current imbalances (i.e. very high fault currents to earth), but we know from RCD testing and test result requirements that RCDs don't operate in less than quarter** of a cycle (5msec) in response to moderate fault currents. Perhaps it's true that they do trip in an electrical sense within that period, but then take appreciably longer than that for the mechanical disconnection to occur.As I recall, an RCD can trip as soon as the sine-wave of an AC supply rises to a voltage where the current flowing reaches its trip point. This iks why, with a fairly significant current, they can trip within less than half a cycle (1/100th of a second at 50Hz)
It's also rising for the 3rd quarter of the first cycle.{** I say quarter of a cycle, rather than the half-cycle you mention, since the voltage is only rising for the first half of the first half cycle}
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