Armoured wire for 24V system | on ElectriciansForums

Discuss Armoured wire for 24V system in the Solar PV Forum | Solar Panels Forum area at ElectriciansForums.net

MalcolmS

DIY
Joined
Nov 9, 2021
Messages
45
Reaction score
5
Location
London
Hi All,
I hope you are doing ok.
I have a question regarding the 24V system. I am going to build a pergola and I could install 4 panels on it. The inverter and batteries would be in a building that is about 3-4m away.
What armoured wire should I put in the ground in advance to connect these 4 panels? I have a trench ready.
Best regards
 
Does the panel / inverter manufacturer not have a recommended spec? You've a balancing act here of cost v resistance (equals less energy at the end).
 
I come across this table. I reckon I have to work out.
 

Attachments

  • [ElectriciansForums.net] Armoured wire for 24V system
    Screenshot_2024-02-21_14-19-03.jpg
    108.2 KB · Views: 30
I come across this table. I reckon I have to work out.
That looks to me like a chart for main loadings for North America, absolutely irrelevant (ish - the physics is the same) to this.

Off the top of my head I would say you're probably looking at 4mm SWA for the best bang:buck ratio but what wattage are the panels?
 
That looks to me like a chart for main loadings for North America, absolutely irrelevant (ish - the physics is the same) to this.

Off the top of my head I would say you're probably looking at 4mm SWA for the best bang:buck ratio but what wattage are the panels?
Thanks for clarifying.
I don't have the panels yet but I home in on JA Solar 460W. In any case aim for panels of this size and wattage.
 
Last edited:
At 240 volts a 10v drop won't be much of an issue at 24v it's a big deal,you would have to work out the minimum accepted voltage at full current and use ohms law to work out the best size of cable
 
460 W @ 24V = 19A per panel
x 4 = 76A
1% VD

therefore .24v / 76A = 0.00315Ω /m max cable resistance
Closest standard matching cable would be 70mm² @ 0.0029Ω /m

allow 5m run by the time you've done a few bends and terminations, this is DC so applies both ways = 10m
= volt drop of .22V / 0.92%.

This is a very hefty cable - the workaround would be not to group all four panels togethers and take each one individually out to the inverter in maybe 2 x 4c SWA's instead - this would change the maths to 16mm² conductors which is far more pleasant on the pocket and the hands installing it!
 
Ok, thank you for your replies.
Now I understand why they install the equipment in the loft not to have to deal with the Voltage drop.
In this case wouldn't be better to just have two separate systems and merge them at 240V to be able to transfer electricity at longer distances.

It's just a hypothetical question and out of scope of the current discussion but currently I have a 10mm SWA in the ground and this is to bring the electricity to the garden but in the future could this be changed to bring the electricity to the house from PV system? Like a kind of evolution from grid to semi-of-grid.
 

Reply to Armoured wire for 24V system in the Solar PV Forum | Solar Panels Forum area at ElectriciansForums.net

News and Offers from Sponsors

  • Article
Join us at electronica 2024 in Munich! Since 1964, electronica has been the premier event for technology enthusiasts and industry professionals...
    • Like
Replies
0
Views
265
  • Sticky
  • Article
Good to know thanks, one can never have enough places to source parts from!
Replies
4
Views
756
  • Article
OFFICIAL SPONSORS These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then...
Replies
0
Views
743

Similar threads

You can use timers to turn ON/OFF circuits during the day to maximize your self-use of solar power. Turn ON low draw circuits such as a 1Kw pool...
Replies
6
Views
918
You only need to switch the lines and the contactor is rated per pole so for example a 16A four pole contactor would be fine.
Replies
1
Views
266

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

YOUR Unread Posts

This website was designed, optimised and is hosted by untold.media Operating under the name Untold Media since 2001.
Back
Top