Panel Isolators - Different Voltages?

I suspect this is going to be the devil's in the detail sort of one.


As a general principle, it's best to isolate everything simultaneously by a single device - so sharing the same isolator sounds like a good idea ... but there is a lot to get right. Where you have a mix of LV and ELV shock protection considerations might mean that the two systems have to be kept properly separated - which might be tricky with adjacent terminals on the same device meaning the wiring systems will have to be close to each other and/or the internal arrangement of the device might not provide complete separation. Similar consideration might apply if a fault between the two systems could do a excessive amount of equipment damage even if it wasn't a shock hazard. Then there's the mix of d.c. and a.c. to consider - d.c. is actually harder to switch, especially where larger currents & voltages are concerned - as there's no automatic extinguishing of arcs every half cycle - so an isolator that's fine for your a.c. supply might not be suitable for the d.c. side - so that might limit your choice. There might be functional considerations too - is the UPS fed supply actually meant to keep things running when things on the normal side are shutdown? - so there might be times when you might need to be able to isolate the two systems independently of each other.


So really a shared isolator is just one option in your tool box - there are many others varying from signage to internal barriers to even work procedures - so you can choose whichever (or combination) best suits each individual situation.


   - Andy.

I suspect this is going to be the devil's in the detail sort of one.


As a general principle, it's best to isolate everything simultaneously by a single device - so sharing the same isolator sounds like a good idea ... but there is a lot to get right. Where you have a mix of LV and ELV shock protection considerations might mean that the two systems have to be kept properly separated - which might be tricky with adjacent terminals on the same device meaning the wiring systems will have to be close to each other and/or the internal arrangement of the device might not provide complete separation. Similar consideration might apply if a fault between the two systems could do a excessive amount of equipment damage even if it wasn't a shock hazard. Then there's the mix of d.c. and a.c. to consider - d.c. is actually harder to switch, especially where larger currents & voltages are concerned - as there's no automatic extinguishing of arcs every half cycle - so an isolator that's fine for your a.c. supply might not be suitable for the d.c. side - so that might limit your choice. There might be functional considerations too - is the UPS fed supply actually meant to keep things running when things on the normal side are shutdown? - so there might be times when you might need to be able to isolate the two systems independently of each other.


So really a shared isolator is just one option in your tool box - there are many others varying from signage to internal barriers to even work procedures - so you can choose whichever (or combination) best suits each individual situation.


   - Andy.