I'm now on my second day quest to find the correct cable on my AC lines.
I'm installing a 3 phase multiplus 2 48/5000 system at home.
For the AC side I can't find a definitive answer on what to do; I understand why, the length of the cable influences the section. But I absolutely can't remember how to calculate this. School is 30 years ago, and I haven't actually exercised that shelf of my brain.
The manual say we need to protect the multiplus input and output with a 50A Circuit Breaker or inferior. Out of experience, I would put a 16mm² cable with 3 wires in; I only need 6 meters to the furthest multi.
Now, in the Victrom professional area, the videos warn several times to not make the cable too big because of the resistance. I get that in a parallel system, I don't get why in a 3 phase system, since all the inverters work independently.
From the manual,
AC-In
The AC input must be protected by a fuse or magnetic circuit breaker rated at 50 A or less, and the cable cross-section must be sized accordingly. If the input AC supply is rated at a lower value, the fuse or magnetic circuit breaker should be downsized accordingly.
Here, no worries, a B curve 50A MCB and 16mm² cable per multi.
AC-out-1
With its PowerAssist feature the inverter/charger can add up to 3 kVA (that is 3000 / 230 = 13 A) to the output during periods of peak power requirement. Together with a maximum input current of 32 A, this means that the output can supply up to 32 + 13 = 45 A. An earth leakage circuit breaker and a fuse or circuit breaker rated to support the expected load must be included in series with the output, and the cable cross-section must be sized accordingly.
Here I believe the manual refers to the 3000 unit, adapting it to the 5000 unit we should read:
With its PowerAssist feature the inverter/charger can add up to 5kVA (that is 5000 / 230 = 21,7A) to the output during periods of peak power requirement. Together with a maximum input current of 50A, this means that the output can supply up to 50 + 21,7 = about 72A. An earth leakage circuit breaker and a fuse or circuit breaker rated to support the expected load must be included in series with the output, and the cable cross-section must be sized accordingly.
For the length of the time the power assist works, I can live with the 72A in 16mm². Am I wrong?
So here, I also place per multi a 50A MCB but maybe with a C curve?
Am I seeing something wrong?
Thank you for your input
Nuno
