Thread: 16mm square twin cable?

Does anyone know where I can buy 16mm square twin sheath electrical cable either online or in Sydney? I haven't been able to find anything online. Cheers, Scoota

Hi bee utey, the current rate marked on Australian sold cable is next to useless and you need to be very careful of this current rate.

The current rate on cable sold here is based on a 50% duty cycle which is how a compressor fridge operates, on off on off.

The problem is than this is not the SAFE maximum current for the cable and it should be rated for a 100% duty cycle rate, as is done anywhere else in the world. If you go to the different cable manufacturer/wholesales sites, they actually list the different cycle rates for their cables.

Back to the 6mm Auto, it’s only 4,5mm2 and if you tried to pull 50 amps down just 0.5 metres of this cable, you would get around a 2 to 3 volt drop and with in just a few minutes, the cable would get so hot you could not hold it without getting burnt.

Hi Scoota, for what your planning to use the cable for, 6B&S or 16mm2 twin cable would be the minimum size but you will still get a voltage drop and you might be surprised at how much voltage drop you will get with this thick cable.

Just to give you an idea of what to expect, just last Thursday I was carrying out some operating experiments on a new isolator.

I needed to do this in a real world situation, so the day before, I discharged two 105 Ah flooded wet cell deep cycle batteries down to 12.04v. Thats a fraction under 50% SoC.

I had these two batteries strapped down in the back of my wife’s D4 and had them connected via 6m of 6B&S twin from the cranking battery, via the isolator and through two sets of 50 amp Anderson plugs ( that 2 x 2 plugs ).

I was not interested in the current draw just the ability for the set up to be able to charge batteries without having problems with the isolator, so I only took voltage readings and didn’t bother with current readings.

Just after starting the motor, the cranking battery voltage was 13.78v and the auxiliary batteries were 12.71v

After 20 minutes of driving, the cranking battery voltage was 13.80v and the auxiliary batteries were 12.90v

After 3 hours and 6 minutes of driving, the voltage at the auxiliary batteries were at 13.28 and was 13.66v at the cranking battery.

The two auxiliary batteries have been sitting for a week now so if I get a chance this afternoon, I’ll load test them and see what they were charged to.

Anyway Scoota, this should give you an idea of what you will get with your set up