Hi Everyone

 

What are your favorite cable sizing methods? I know there are a few online calculators , but really keen to hear what methods you guys favor when it comes to sizing cables for solar etc. 

Regards

E

This is what I use at work.

Cable ratings is unfortunately for 4 core SWA cabling, except where stated Single Core.

 

So a 25mm 4 core cable is rated safely at 110Amps.

Single core PVC cable is then rated 140Amps.

25mm = 4 AWG (American Wire Gauge)

 

Usually your maximum volt drop will limit the maximum current carrying capability of the wire, thus if you size by volt drop your cable should be able to handle the current that will run in it.

 

You need to look at the current carrying capability of copper and from there work out the correct size:

You will need:

The maximum voltage drop you want to allow,

The system voltage,

Maximum current that will be carried by the cable,

The length of the wire,

 

Equation for volt drop is:

Volt drop = (0.0164 x current(A) x 2 x distance (m))/(wire size(mm2))

 

Thus if you rearrange the equation you can get the wire size that is needed.

 

The higher you can push your voltage the smaller your volt drop will be.

Hi All

 

I need to purchase 12m of cable for my inverter (Axpert 5kw) Inverter to DB run and then the same for the Inverter to Load run (seperate DB).

 

No choice as Inverter is away from the DB to avoid the noisy fan factor...

 

What size and type to I ask for?

 

Axpert 5kv recommend 100amp for AC charger but I wont charge at nearly this initially - want to future proof..

 

Thanks

Mark

 

 

What is the size of your main breaker? That is the maximum you could take anywhere on your property. You need to work out what is the maximum current draw in bypass mode going to be (up to a max of 50A - from Axpert manual).  Your inverter max output is going to be about 22A. 

 

Cabling and breakers (from another forum).

 

1.5mm or smaller - 10A or smaller (1A, 2A, 6A, and a few others are options in terms of breakers - but $$$$)
2.5mm or 4.0mm - 20A or smaller
6.0mm or 10mm - 32A or smaller
16.0mm - 40A or smaller

What is the size of your main breaker? That is the maximum you could take anywhere on your property. You need to work out what is the maximum current draw in bypass mode going to be (up to a max of 50A - from Axpert manual).  Your inverter max output is going to be about 22A. 

 

Cabling and breakers (from another forum).

 

1.5mm or smaller - 10A or smaller (1A, 2A, 6A, and a few others are options in terms of breakers - but $$$$)

2.5mm or 4.0mm - 20A or smaller

6.0mm or 10mm - 32A or smaller

16.0mm - 40A or smaller

Thanks Chris

 

That helps,

 

I got rid of the electoric geyser  a year ago so think I'll go with that 20A breaker that was used for this for a start and set the Axpert lower and slower charging - not alot of load at the moment...

 

Regards

Mark

OK. the cabling for my output is 6mm  which gives me a bit of leeway in terms of output and input is 4mm as I am limited to 16A per phase on my diesel generator (10kVA 3 phase). You could probably do the same.  

Hi All

 

I need to purchase 12m of cable for my inverter (Axpert 5kw) Inverter to DB run and then the same for the Inverter to Load run (seperate DB).

 

No choice as Inverter is away from the DB to avoid the noisy fan factor...

 

What size and type to I ask for?

 

Axpert 5kv recommend 100amp for AC charger but I wont charge at nearly this initially - want to future proof..

 

Thanks

Mark

Hi Mark,

 

For the inverter supply you should provide a 50A feed, therefore 10mm.sq wiring is needed for both input and output. 10mm.sq is also the largest wire size that fits in the terminals.

 

For the batteries, you would need 25mm.sq - depending on your battery bank size.

Hi Mark,

 

For the inverter supply you should provide a 50A feed, therefore 10mm.sq wiring is needed for both input and output. 10mm.sq is also the largest wire size that fits in the terminals.

 

For the batteries, you would need 25mm.sq - depending on your battery bank size.

Thanks for the feedback. 

 

My old farm board won't handle 50A so I have settled on 6mm and will set the Axpert to 20A or max 30A. (6mm is spec'd to 38A).  30A may not even be feasible...

 

I will add panels in future to help with the charging of the battery bank but currently have low load and small battery bank.

 

Regards

Mark

That 30AI am lead to believe is DC so you should only be drawing about 6A AC. What you need to cater for is the draw in bypass mode.

About the noisy fan on an Aussie site it seems that the noisy fan has been cured with a firmware upgrade. My axpert is next to my desk - we will see when I at last switch on tomorrow.