CAUTION! The UPS must be connected to a grounded AC power outlet with fuse or circuit breaker
protection. DO NOT plug the UPS into an outlet that is not grounded. If you need to de-energize this
equipment, turn off and unplug the UPS.
I read this as meaning an earth rod is required, as the whole idea of a UPS it to give power when the grid is down, and if the grid is down one can't rely on any earth from the DNO be it TN-S or TN-C-S.
As to linking neutral to earth during a power failure, nothing in the spec says it does this, the output is 6 x 13 amp sockets, 3 UPS and 3 direct, and no reference to RCD or any earth fault detection being built into the unit. Manual is available here I wonder if this is normal or not?
I have a far larger unit, 5 kW on 6.4 kWh battery, which does link earth and neutral with a power failure, it has got an earth rod, earth fault detection in the inverter plus RCD type A sockets, and my RCD tester shows they trip at 21 mA and well within 40 mS and a reasonable loop impedance. So I'm alright, Jack, but 780 watt is a far smaller unit, with equipment being plugged directly into the UPS with 13 amp socket. At half load only got 9 minutes, so not a big deal, mine 6 hours and still 37% left running whole house with a power failure only selected sockets, so may never run out if enough sun during the day.
So with the small UPS is lack of earth rod and RCD a real problem, or something we can turn a blind eye to?
Continue reading...
protection. DO NOT plug the UPS into an outlet that is not grounded. If you need to de-energize this
equipment, turn off and unplug the UPS.
I read this as meaning an earth rod is required, as the whole idea of a UPS it to give power when the grid is down, and if the grid is down one can't rely on any earth from the DNO be it TN-S or TN-C-S.
As to linking neutral to earth during a power failure, nothing in the spec says it does this, the output is 6 x 13 amp sockets, 3 UPS and 3 direct, and no reference to RCD or any earth fault detection being built into the unit. Manual is available here I wonder if this is normal or not?
I have a far larger unit, 5 kW on 6.4 kWh battery, which does link earth and neutral with a power failure, it has got an earth rod, earth fault detection in the inverter plus RCD type A sockets, and my RCD tester shows they trip at 21 mA and well within 40 mS and a reasonable loop impedance. So I'm alright, Jack, but 780 watt is a far smaller unit, with equipment being plugged directly into the UPS with 13 amp socket. At half load only got 9 minutes, so not a big deal, mine 6 hours and still 37% left running whole house with a power failure only selected sockets, so may never run out if enough sun during the day.
So with the small UPS is lack of earth rod and RCD a real problem, or something we can turn a blind eye to?
Continue reading...
