When I built my 1st install I repeatedly came across, as being “the standard”, that the voltage drop (VD) in the supply to any inverter should not be no more that 1%. My SWA supply cable from the house to the outbuilding where the gear is installed was sized appropriately. (6MM2) I never saw any reference to this 1% requirement in the Victron data sheet but I have realised that maybe the reason why, is that the ac volts in, to the MP has a range of 187 to 265. Would I be correct in interpreting this, that I now have a greater tolerance to voltage drop? If allowed a VD of 2 % (very conservative in a normal power supply) the cable would be within its capability of carrying 40A rather than 32A, which could be useful in the future. Anyone able to comment on this.
You might be confusing AC vs DC voltage drop.
No I am not, I should have been more specific in my question. I am talking about AC supply cable to an inverter which also acts as the feed into the system of inverted power. The 1% drop in the engineering design of a system is to ensure that there is no nuisance tripping of the inverter when there are fluctuations in the grid supply voltage. It does seem counter intuitive that such a limit is imposed on the design when the grid varies by a lot more than that. But it is to do with ensuring that the inverter does not exceed its internal safety limits when the grid get close to its limits. I should have asked does the 1% rule apply to Victron inverters. Maybe it needs a Victron engineer to answer the question. It had occurred to me that going to a Victron MP may have given me an advantage in any further developments I may want to make.
Victron has the answer if one knows where to look. Found this in wiring unlimited.
The Victron Energy Toolkit app also has a provision for calculating AC wiring for 120, 240 and 400Vac systems. When using the app, the aim is to select a wire size so that the voltage drop stays below 2.5%.
I can got to 40A with a VD of 1.9% with my SWA according to the toolkit which in line with a different calculator I use, which gave 2%. So the Victron VD tolerance is more generous than the industry design aim of 1%.
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