Connecting a Three-Phase Victron Energy Storage System

Steps

1. 1

   Step 1: Preparing the meter cupboard

   I start by making a small opening in the side of the existing consumer unit to connect a new consumer unit next to it. I want extra room to expand later, including a bypass, and I want my own setup completely clamped off.

   Working with the cover closed makes the work safer while I switch off the group. I mount the extra consumer unit against the wall and make a nice doorway between the two units.

   What I used

   Item	Amount	Notes
   consumer unit	1	extra unit for expansion

2. 2

   Step 2: Running cables between the meter cupboard and the shed

   I pull two five-core 6 mm2 power cables through trunking from the meter cupboard to the shed where the energy storage stands. From the shed, I run another five-core 6 mm2 cable back to the meter cupboard to feed the groups.

   I need to protect these cables, so I mount an extra box against the wall in the meter cupboard. The narrower printer caps do not fit the cables, so I use my 3D printer to print a custom risk cube to neatly cover them.

   What I used

   Item	Amount	Notes
   YMvK cable 5x6 mm2	2	5 meters each, running between meter cupboard and shed

3. 3

   Step 3: Wiring the meter cupboard

   I mark the cables to track which one goes to the shed and which comes from it, then strip a section of the outer sheath to move the wires easily. I set the DIN rail back into the new consumer unit and place a 4-pole earth leakage circuit breaker.

   Later, I will install three double-pole earth leakage breakers in the shed, but I add an extra earth leakage breaker in the house for extra safety. I connect the incoming phase wires in color order, connect the earth wires to the earth rail, and finally connect the set to the main house distribution board.

   Warning

   Twisting cables between neutral and phase creates a 440V reading and can cause a 400V short circuit that destroys equipment, so check your connections twice.

   What I used

   Item	Amount	Notes
   earth leakage circuit breaker	1	4-pole
   DIN rail	1	reinstalled in consumer unit

4. 4

   Step 4: Wiring the shed and the MultiPlus units

   In the shed, I strip the incoming cable from the meter cupboard and route the wires to a main switch rated for 40 amp, which lets me disconnect the system from the grid while working on it. I also use warning stickers to keep track of what everything is.

   For the MultiPlus inverters themselves, Victron advises against using massive copper wires, so I use flexible 6 mm2 cables. I connect the neutral from the main switch to the AC input on the left pole of the first unit and loop it to the others, then connect the phase wires to individual phases so each unit gets its own phase.

   Tip

   AC1 always has voltage regardless of grid presence, so feed the AC input carefully and place a 25A backfeed circuit breaker on the returning cable from the shed to the meter cupboard.

   What I used

   Item	Amount	Notes
   flexible cable 6 mm2	3	phase cables
   main switch	1	rated for 40A
   overload circuit breaker	1	25A for outgoing power

5. 5

   Step 5: Finishing and enclosing the shed installation

   I place a terminal block for the peripheral earth connections so all ground wires come together neatly. Officially, all cables should be double-insulated with PVC pipe between the MultiPlus and the cable groove, but since I have plenty of space and will add pipe later, I leave it for now.

   To finish the enclosure, I use my 3D printer to make a housing in the same blue color as the Victron units. I place it over the earth leakage and breaker switches to protect them and give the setup a clean aesthetic look.

   What I used

   Item	Amount	Notes
   terminal block	1	for peripheral earth connections
   3D printed housing	1	blue color matching Victron units

6. 6

   Step 6: Takeaways

   • Always double-check your phase and neutral wiring to prevent 400V short circuits.

   • Use flexible 6 mm2 cables for the MultiPlus units as advised by Victron.

   • Add a main switch in the shed to easily disconnect the system from the grid.

   • Place backfeed circuit breakers on returning cables to regulate incoming and outgoing power safely.