This site is advertising 6mm twin sheath as
Our cable is measured by the cross sectional area of the copper, eg. Our 1.84mm squared cable is equivalent to Automotive 4mm. This is very important when calculating voltage drop Cable can be cut to size and the staff can assist you in making the best selection. Price is per meter
so in theory it's AW6
price is $6.90 a meter
http://www.springers.com.au/product.asp?SKU=635
Last edited by timddo; 10-11-2010 at 10:16 AM. Reason: 6mm twin shealth cable
Not quite. That link shows 6mm2 cable, which is about somewhere between 9 adn 10 AWG.
8mm2 is roughly 8 AWG, or 8B&S. AWG and B&S are the same.
I have no idea what automotive cables are and how that measurment works. As far as I am concerned you should go on the actual conductor size
What the maximum current load of your winch?
I intend on living for-ever....so far so good
30Amps. is the circuit breaker.
so AW8...
I though i mite get it cheap.at $6.9 instead of $11.00
oh well. The current installation is like 2mm x 2 cables ( dogy dealer).
Apparently automotive cabling includes the insulation.
30Amps is not that much. The smaller stuff (6mm2) will carry that much current. However, depending on the length of the cable you might get to much voltage drop.
How long is the cable going to be? We can work all that out for you!
AndyOriginally Posted by TheRealAndy
About 6.5 meters or so to the switch, then it's an extra 2 meters to the winch
For 6mm2 cable, the voltage drop at 30A for an 8.5m run is roughly 3V, so a little to much.
Using 10mm2 cable, the voltage drop is about 0.9V. I would consder this acceptable
10mm2 solar twin is a popular cable at the moment, some of the bias stores have it for use with lecky outboards.
Going to the solar shops for this mid sized cable is not at all a bad thaught......they will be using the stuff in volume with all the subsidised solar arround these days.
cheers
Its the details, those little details, that make the difference.
Thanks from me too. Could you give me an approximate voltage drop for a 6mm2 cable - 16amp draw with a 4 metre run?
It is not a big winch, co-located with a dedicated battery (in a separate compartment of course) - and solar panel for recharging - all sited at the bow. The run back to the helm position is 4 metres.
I think the wire might be enough and have installed the lot but confirmation from an expert would be greatly appreciated.
Over a one way cable run that long that'll be a considerable v drop if you only use say 8AWG/8sqmm cable and its still significant even with about 10sqmm stuff...but probably acceptable.
You really dont want to starve anchor winches.
Would need 10sqmm minimum i reckon working off what my local guy stocks. As a price guide he retails 10sqmm tinned for about $4/m and the 16sqmm is about $7 so its quite a jump up in price for the real big stuff over that kinda long run.
Tigermullet....if its one way 4m about 3-4% i reckon. Andy might know better tho coz i think he's knee deep in a spaghetti of wires at the moment.
Thanks very much Deckie. The 4m distance is one way because I had to go beneath the deck on an angle and then up to the helm position. My problem is not understanding various gauges - the wire was purchased as 6mm but what that means in mm2 is beyond me. The only thing I could go on was that the wire (not twin sheath) was advertised as being suitable for, or rated at, 45 amps.
If the battery is located close to the winch, why are you running all the way back to the helm with the high current cabling? a relay set up and light cabling to the winch would be the way to go.
As far as the voltage drop in question.
its around half the distance and around half the current so the voltage drop will be arround a quarter of the previous example....and that is with out any tables or serious maths.
On the mater of voltage drop and motors........ in our boats we only have 12 volts.....so if one or two volts go missing it is s real problem.
In addition motors can draw quite a lot more than their rated current on start up and near stall.........when a motor labours due to lack of voltage, it will be trying to operate near stall so the nearer stall the more current is drawn..and the cycle continues.
So it is very important to avoid voltage drop in large DC motors.
You have spent good money on a winch.....heavier cable never hurt.
cheers
Its the details, those little details, that make the difference.
Ahhh ok thats a different thing. Bizzarre how screwed up and confusing these wire sizes are. Yepp 6mm cable is rated about 45A but thats smaller than 6sqmm which measures the cross sectional area of the internal wire itself (dont quote me on that) but probably the only way to keep it real and to guarantee u get the right stuff coz of all the different bloody names.
There's AWG/B&S/mm/sqmmand i think the car racket even do it differently again. The clue is u said u bght it as rated 45A.
Someone correct me if wrong but this is how screwed up it is...the 6mm wire u have is probably 12AWG or 12B&S or about 3sqmm stuff
In which case its smaller stuff than i thought and the v drop would probably be most likely about 6% over 4m. Sorry bud.
In general 12V stuff with motors suck the most of anything onboard...the stuff we get from say Whitworths/Bias etc is quoted usually as 4mm or 6mm or 8mm etc but the reason sqmm is generally used is because its how much is inside the insulation that matters. For general wiring onboard 4mm (18AWG/1sqmm i think ??) is plenty, u may want to go to 6mm for things like long cable runs to bigger bilge pumps or short runs to thirsty spotlights...then 8mm as they call it (which i think is about 8AWG/8sqmm and rated to about 80A) is used for stuff such as connecting battery to dist panel at the dash and maybe short runs to small winches.
The problem is distance...even tho the wire/cable might be rated to say 45A, once u start taking 16A over 4m u get V drop which can only be cured easily by simply going to a bigger cable.
If its 4m to the winch i'd be looking at 8AWG/8sqmm which i think is sold as 8mm cable at the big chandlery's ..which is 80A cable
Sparkies are evil...why cant they just give us one bloody cable description.
Thanks Oldboot I am beginning to see the problem. I just followed the wiring diagram - the winch operating switch has 4 terminals 2 from the battery and two from (or to) the winch. I wouldn't know a relay if I fell over one.
I used the recommended size (as far as I understood it) and, as far as I can determine, with a cheap multimeter, there is nil detectable voltage drop i.e., volts read at the battery - and at the switch - were exactly the same, 12.7 volts. Of course, the voltage drop at the winch motor could be different.
Lol. AWG is the Same as B&S, thats the yankee wire guage. The Brits have (had) SWG, which is different to the yanks. Most european countries now use the IEC metric (mm2) size now, including australia. The standard sizes I remember are 1 1.5, 2.5, 4 , 6, 10, 16, 25 and 35. They go lower and higher, but I dont recall any of them. Most smaller stuff is in AWG or SWG.
1 volt of loss is ok, and should not affect motors to badly in a 12V system. If you need every last little bit of torque and that 1V is making a difference then you should be considering the next size up in motor.
Now the auto industry is really screwed, and I dont know how it works, because from my limited understanding as a sparky, you can only derate cable capacity based on insulation, you cant calculate current and voltage drop. So I dont get it. I am sure there is some common sense in there somewhere.
Tigermullet, I have a spreadsheet that I made for calculating voltage drop, based on olex cable resistance specs. Will do your calcs tomorrow when I get to work.
If anyone is looking for more info, the olex handbook is an excellent source of material. You can download it from the website, just look in the low voltage section.
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