Cable Diameter for Inverter Installation- Advice Please (1 Viewer)

Emmit

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Aug 14, 2009
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Morning All,

Could some kind Funster please offer their advice re above.

I have a spare 1000w Pure Sine Inverter available.

I already have a 300w Inverter wired up to the Van Batrtery but wish to instal the
bigger unit instead. I appreciate that it would drain the battery very quickly if I were to use it
for any length of time etc but I would like to know what diameter of cable I should use.

I appreciate that the cable that came with the 300w jobby isn't man, (or woman) for the job
and I also appreciate that the cable should be fused.

Two questions. Assuming the cable would be not longer than 18", what size cable and second,
what size fuse.


Thank you in advance
 

funflair

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This is a great resource for checking cable size, when I fitted our inverter I wanted less than 3%


I would be tempted to go for 35mm as it will be still quite manageable and keep the voltage drop down.
 
Apr 27, 2016
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I would like to know what diameter of cable I should use.
Cables are normally specced by their Cross-Sectional Area (CSA) rather than their diameter. CSA is measured in square millimetres, for example 35 square millimetres or 35mm2. The diameter of that cable is about 12mm, including the insulation.

The reason they use the area rather than the diameter is that the amps capacity depends on the area of the copper, not the diameter.

A complicating factor is that in the websites often the last '2' on the 35mm2 is accidentally dropped, so 35mm2 cable is described as 35mm.

If you want to know the diameter of the cable there is a table here:
 

Bart

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Jun 4, 2016
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the size of your cable also depends on the length that the cable needs to run.
 
Jan 11, 2022
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Was always told cable should be as fat as you can and as short as you can, thatā€™s in old money talk.
Get the inverter as close to battery as you can and use good CSA cable to reduce volt drop.

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Lenny HB

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Oct 18, 2007
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Two questions. Assuming the cable would be not longer than 18", what size cable and second,
what size fuse.
16mm sq will be more than adequate for such a short run fused at 100 amps.
If you don't have Lithium you are going to need 500 ah of batteries to support 1000 Watts if you use it at full power.
 
Last edited:
Dec 31, 2010
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Good little app here from our boy's in blue šŸ’™šŸ˜‰

 

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