I am confused as to whether to run my inverter/battery cables in ducting or not. My natural instinct is for them to be in free air and indeed the Multiplus manual states not to run cables in closed conduit. Yet I see countless examples of installs looking very neat and tidy with the cables tucked away in trunking of one sort of another. I am torn between my instinct/ Victron advice and desire for neatness. What does the community think?
Nice job. Yes that is the way to do the professional way which I am leaning towards. Dearer than plastic the slotted stuff does allow some ventilation though as well as convenient cable entry and exit. The install in the photo, (presume it is yours) given the size of the job you really could not have done it any other way in order to make sure cables were not bundled as they would be in trunking.
Thanks, yeah it’s my project and my work.
They’re proper high-quality metal ventilated cable trays with a full set of fittings for routing and securing cables across multiple depth levels.
Where electricity’s involved, there are no cost-cutting compromises, only the wiring regulations, safety standards, local grid regulations, manufacturer requirements, and personal responsibility.
The simple answer is…
If you are ducting you use higher gauges of wire if you are being serious about power. (Because heat derates things).
If you are crazy serious there are proper engineering calculations that should be done using ambient and other factors.
Duct jelousy… I wish i could get stuff like that.
These are KOPOS cable trays, the Jupiter series.
I only ever use theirs. Top quality and a wide range of fittings in the catalogue.
My previous system Delios inverter (died) and 10kW BMZ battery came as a kit. The battery cables were 50mm2 and the combo came with 16mm2 to join the battery to the inverter that had 16mm2 din rail terminals. I questioned whether the 16mm2 was ok and was told it was fine. I kept this as short as possible but at a draw of 5kW from the battery that 16mm cable got warm the amps going through I calculated was 90A just within the cable limit. Nevertheless not a very good design, that heat was wasted energy and as the battery volts dropped cable would get hotter.
Post picture and details when complete it would be nice to see.
That’s going to cost a fair bit 
To the specific question, I see it like this. If the system is in an enclosed, secured dedicated electrical space, then do not use enclosed ducts. If the system is in anyway exposed to elements, people, pests etc, then use enclosed ducts, but do the de-rating calculations and follow code for duct fill rates.
There is a whole language for this you can look up. Melectrician free app on iphone is useful for quick checks. E.g. Method F is cables installed in free air, method B1 is insulated conductors in suspended cable trunking. You choose your installation method and it helps you calculate cable sizes. See attached pdf of the methods.
Open the app, choose IEC (my location uses IEC code) then Wire Sizing calculator, choose installation method and enter the other details to calculate, and also to export the calculations as a report.
MElectrician.pdf (199.2 KB)
Alex
I have decided that the battery, inverter and MPPT power cables i.e. those going to the Lynx, will be on cable trays, The AC to the inverter in a trunking of their own, and data cables in a separate trunking of their own. Work is well advanced took delivery of 3 Pytes V12 batteries this week.
Awesome, share pictures when you’re done. We always like to see those.