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Executive Member
- Joined
- Sep 19, 2005
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Hi everyone
I currently have the following setup: (Just for sake of clarity)
1x Cotek SK1000-224 24 volt 1000 watt Sine Wave Inverter
2x 100Ah Battery (Series)
2x Noco G7200 Smart Chargers (Series)
The inverter doesn't have a transfer switch. What I want: Transfer switch at my breaker panel (ideally).
Note I am not wiring this myself, I am simply trying to understand the general setup for planning purposes.
So far I have found two possible opitons:
- 2x 2PST (2 pole single throw) Contactor with mechanical interlock between them (and eletrical type of interlock with two relays to prevent both contactors being powered at the same time)
- 1x 3PDT (3 pole double throw) Relay such as this. These have DIN rail mounting options and have a 230VAC coil so you can simply wire the inverter to the NO wires and the coil is powered from Eskom. This is somewhat simpler than the Contactor because you have a single relay and make use of the NO/NC contacts. I am however slightly concerned about how well such a relay will cope switching the current.
In both cases the relays have rated transfer times >= 20ms so as far as I am concerned I do not need to sync my inverter to mains (eg. 1 cycle @ 50Hz = 20ms)
My questions:
How is the ground wire wired with this kind of setup? I definitely want to avoid bonding the Inverter and distribution board (DB) ground wires but I suspect that is what is required for it to be safe. eg. switching ground using a relay seems very unsafe and contrary to the idea of a ground (eg. high-z ground when it is switching is very dangerous!)
Generally speaking I envision that the wiring would be as follows:
Eskom -> Mains breaker -> Change over switch breaker for mains (say 20a breaker) -> Change over switch (relay) -> Secondary breakers after changeover switch (eg. lights, plug breaker, etc.)
Intervert -> Inverter breaker (say 20a) -> Change over switch (relay) -> same as above
Any input appreciated
I currently have the following setup: (Just for sake of clarity)
1x Cotek SK1000-224 24 volt 1000 watt Sine Wave Inverter
2x 100Ah Battery (Series)
2x Noco G7200 Smart Chargers (Series)
The inverter doesn't have a transfer switch. What I want: Transfer switch at my breaker panel (ideally).
Note I am not wiring this myself, I am simply trying to understand the general setup for planning purposes.
So far I have found two possible opitons:
- 2x 2PST (2 pole single throw) Contactor with mechanical interlock between them (and eletrical type of interlock with two relays to prevent both contactors being powered at the same time)
- 1x 3PDT (3 pole double throw) Relay such as this. These have DIN rail mounting options and have a 230VAC coil so you can simply wire the inverter to the NO wires and the coil is powered from Eskom. This is somewhat simpler than the Contactor because you have a single relay and make use of the NO/NC contacts. I am however slightly concerned about how well such a relay will cope switching the current.
In both cases the relays have rated transfer times >= 20ms so as far as I am concerned I do not need to sync my inverter to mains (eg. 1 cycle @ 50Hz = 20ms)
My questions:
How is the ground wire wired with this kind of setup? I definitely want to avoid bonding the Inverter and distribution board (DB) ground wires but I suspect that is what is required for it to be safe. eg. switching ground using a relay seems very unsafe and contrary to the idea of a ground (eg. high-z ground when it is switching is very dangerous!)
Generally speaking I envision that the wiring would be as follows:
Eskom -> Mains breaker -> Change over switch breaker for mains (say 20a breaker) -> Change over switch (relay) -> Secondary breakers after changeover switch (eg. lights, plug breaker, etc.)
Intervert -> Inverter breaker (say 20a) -> Change over switch (relay) -> same as above
Any input appreciated
Last edited: