Evening gents, bored in work this evening so decided to try and get your input on something. We've recently had a new Emergency Care Centre built at my hospital. As you probably know, in hospitals there are 'essential' and 'non-essential' supplies (self explanatory as to why they're called that). The usual set up is as follows..
Example being a ward area..
2 supplies are run to the LV switch room in the ward corridor (This LV switch room usually supplies 4 different wards). One is essential and the other non essential. We supply with an open bus coupler between the two, so that in the event of a fault on either of the supply cables, we can simply isolate the faulty cable and close the bus coupler, as both cables are big enough to cope with the demand of supplying both essential AND non essential.
However, in the new ECC building the system is completly different, and is as follows..
2 supplies are run to the LV switchroom, the bus coupler is closed and the essential breaker is switched off. Meaning that the 'non-essential' supply cable is supplying both 'non-essential' AND essential. Still with me?.. In the event of a fault on the 'non-essential' supply cable, the bus coupler would open circuit and the essential breaker would supply only the 'essential' side of the DB.
Long winded i know. I personally prefer the first set up as i would argue that, say for instance, we lost a phase on the essential cable. We wouldnt know anything about it until the fault on the 'non-essential' supply cable arose, at which point, we would have lost both supplies and we would be so far in the s**t its not worth contemplating!!
I understand that the chances of this actually happening are thousands to one, but needless to say I think all scenarios, or at least most scenarios should be covered!
Apologies if its not the easiest to follow, im hopeless at trying to explain things in text. Lee
Example being a ward area..
2 supplies are run to the LV switch room in the ward corridor (This LV switch room usually supplies 4 different wards). One is essential and the other non essential. We supply with an open bus coupler between the two, so that in the event of a fault on either of the supply cables, we can simply isolate the faulty cable and close the bus coupler, as both cables are big enough to cope with the demand of supplying both essential AND non essential.
However, in the new ECC building the system is completly different, and is as follows..
2 supplies are run to the LV switchroom, the bus coupler is closed and the essential breaker is switched off. Meaning that the 'non-essential' supply cable is supplying both 'non-essential' AND essential. Still with me?.. In the event of a fault on the 'non-essential' supply cable, the bus coupler would open circuit and the essential breaker would supply only the 'essential' side of the DB.
Long winded i know. I personally prefer the first set up as i would argue that, say for instance, we lost a phase on the essential cable. We wouldnt know anything about it until the fault on the 'non-essential' supply cable arose, at which point, we would have lost both supplies and we would be so far in the s**t its not worth contemplating!!
I understand that the chances of this actually happening are thousands to one, but needless to say I think all scenarios, or at least most scenarios should be covered!
Apologies if its not the easiest to follow, im hopeless at trying to explain things in text. Lee
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