Connecting the Selbro Victron Home Battery Setup with Emergency Power

Steps

1. 1

   Step 1: Safety warning and preparation

   I start by explaining that I am going to connect the Selbro Victron home battery setup in the meter box with an emergency power function. Since we are working with high voltages in the meter box, you should only do this if you really know what you are doing. If you are in doubt or unsure, call an electrician to help you with this step.

   Warning

   Now we are going to work with high voltages in the meter box. Do this only if you really know what you are doing.

2. 2

   Step 2: Shutting off power and removing covers

   I completely disconnect the incoming current and the outgoing current from the Victron setup to make sure no power comes back from the shed to the meter box. I also switch off the extra earth leakage mat in the meter box and turn off the main switch of the house so the whole house is without power. Then I remove the covers to get easy access everywhere and use a meter to check that all voltage is truly gone because safety comes first.

   What I used

   Item	Amount	Notes
   meter	1	To check that voltage is gone

3. 3

   Step 3: Rewiring the main switch and residual-current devices

   The meter box is rebuilt with four cables running from the main switch to the residual-current circuit breakers, consisting of one blue neutral and three black phases. I disconnect these wires from the residual-current circuit breakers and the main switch. I have placed an extra residual-current circuit breaker that goes to the shed and feeds the AC-in of the Victron setup.

   What I used

   Item	Amount	Notes
   residual-current circuit breaker	1	Extra unit placed for the shed and AC-in

4. 4

   Step 4: Connecting AC input and output from the shed

   Energy from the main switch goes through the residual-current circuit breaker and a 6 square millimeter cable to the shed to feed the AC input. To use emergency power, I use AC output one which runs through a 25 ampere breaker in the shed, comes back through the wall to the meter box, and connects to five returning cables. The earth wire is already connected to the earth rail and linked internally.

   What I used

   Item	Amount	Notes
   6 mm² cable	1	Feeds the AC input from the shed
   25 A breaker	1	In the shed for AC output one

5. 5

   Step 5: Connecting phase and neutral wires

   I connect the phases where the wires were previously placed between the main switch and the earth leakage. The third phase gray cable is routed to the third residual-current circuit breaker and connected to its phase terminal. We do the same for the black and brown wires on the first and second residual-current circuit breakers.

   Finally, we connect the neutral wire, and since there are bridges between the three residual-current circuit breakers, connecting the neutral to one connects them all at the same time.

   What I used

   Item	Amount	Notes
   gray cable	1	Third phase
   black cable	1	Second phase
   brown cable	1	First phase

6. 6

   Step 6: Tightening screw contacts and checking voltage sides

   It is advisable to go over all screw contacts and tighten them once to make sure everything is properly and tightly secured. It is very important to know that the main switch has one side that does not carry voltage, while the other side still carries voltage. Therefore, we do not need to tighten the non-voltage side, but we can tighten the ones we just connected to ensure everything is secure.

7. 7

   Step 7: Partially closing covers and powering up the system

   I partially close the covers so I can still access the wires to measure if everything arrives correctly. Before switching the set on, I turn off the residual-current devices so no power goes to the house, and I also turn off the solar panels. Then I switch on the main switch, turn on the residual-current circuit breaker to power the Victron setup, and switch on the extra main switch in the shed.

8. 8

   Step 8: Measuring grid voltage and enabling MultiPlus units

   I measure the mains voltage on each MultiPlus unit and record 227 volts on the first, 225 volts on the second, and 217 volts on the third. Then I switch on the MultiPlus units and confirm they are on. Next, I use the multimeter on alternating voltage to measure the AC output and record 222 volts, 225 volts, and 221 volts.

   MultiPlus Unit	Grid Voltage (V)	AC Output Voltage (V)
   1	227	222
   2	225	225
   3	217	221

   What I used

   Item	Amount	Notes
   multimeter	1	Used for measuring AC and grid voltage

9. 9

   Step 9: Enabling outgoing current and residual-current devices

   I turn on the outgoing current so power can flow to the meter box and feed the residual-current circuit breakers. I verify the voltage arriving at the residual-current circuit breakers by measuring the lower two contact points, recording 220 volts, 227 volts, and 223 volts. Finally, I switch on the residual-current devices, noting a slight peak voltage at the capacitors which is completely normal.

   Contact Point	Measured Voltage (V)
   1	220
   2	227
   3	223

10. 10

    Step 10: Testing the emergency power function

    The entire house now receives power from the AC output of the MultiPlus units. When I turn off the main switch, the whole house stays powered because we are running on the battery pack, proving the emergency power function is fully functional. A buzzer sounds to give a notification that the power has dropped and there is no grid voltage, but everything in the house stays on.

    When I switch the main switch back on, the Victron switches back to grid power.

11. 11

    Step 11: Reviewing Home Wizard and VRM app data

    I put the panel cover back on to finish the setup and open the Home Wizard app on the PC to review power usage. I analyze the chart showing normal nighttime standby use, morning power peaks, and solar power generation. During the video recording, the house was disconnected from the grid, showing zero grid usage and then smooth transition to battery power using only 15 to 18 watts from the network.

    The VRM portal similarly shows a total house usage of 408 watts, with 16 watts coming from the grid and the rest from the battery pack.

    What I used

    Item	Amount	Notes
    Home Wizard app	1	Used to monitor power usage
    VRM portal	1	Used to monitor system energy flow

12. 12

    Step 12: Takeaways

    • Always turn off the main power and verify with a meter before working in the meter box.

    • An extra residual-current circuit breaker is needed to feed the Victron AC-in from the shed.

    • Connecting the neutral wire to one residual-current circuit breaker connects them all due to internal bridges.

    • The emergency power function keeps the entire house powered seamlessly when the grid goes down.

    • Monitoring apps like Home Wizard and VRM confirm that the house draws minimal power from the grid while running on batteries.