Extension lead on compressor

I would be using 5 AWG......stupid USA standard ........or in "proper" size, 16mm2 cable.

How about 8 (or 5) Gauge - no nationalism there. Or Browne & Sharpe (B&S)? That's a British standard.

Agree, neither is better than mm2. Do the Yanks do mm2?

And none is as stupid as auto cable sizes in mm diameter, as used widely in Australia, where the cable size includes the plastic insulation. Yep, a hair of copper in a thick plastic tube = 6mm. It's BS, and that's quite different from B&S. LOL

I always thought B&S stood for Battery & Starter.

Thanks for your advice Frank

"Or Browne & Sharpe (B&S)? That's a British standard."

Apologies, Gronk, that's quite wrong.

Brown & Sharpe, an American company, developed their wire gauge in the mid 19th century. It subsequently became AWG. Link

The Brits had a number of standards through the ages, culminating in their own Standard Wire Gauge (SWG) in 1964. According to the same link, that was withdrawn and replaced in 1986 by the metric standard.

Frank, the yanks don't even do mm let alone mm2.

Thanks Peter

agree : I made up an extension air hose recently .. just used the regular hardware hose 100 psi as its not under huge pressure . In this case i would go for a larger diameter hose for the extension from the pump & then the existing hose . after all how often is it going to be used ??

Thanks Mark

Thanks bellony.
That seems like a good move
Ian

Came here to say the same thing - cut the compressor lead 30cms from the end and add in 2 Anderson plugs. Then you can plug it into the back of the car or use the current clips.

Make lead long enough for the compressor to sit on the ground atleast

I also split the compressor leads and added 2 Anderson plugs. Don't forget to leave the car motor running when the compressor is. You don't need to have inflated trailer tyres at the expense of a flat starter battery.

If you are about to fit an Anderson plug at the rear of the vehicle just ensure that the wiring from the battery in the engine bay to the Anderson plug is of sufficient size to carry the load. Some portable compressors such as the ARB twin motor one have 50 amp fuses, anywhere near that level of current could overwhelm light wiring to an Anderson plug.

When pumping water from creeks etc, I used to run a 50m lead from the car to the pump but the voltage drop was massive.
Now I just take a lightweight 50a/h lithium batt down to the creek and use that to power the pump.

thanks RMD

thanks Phil

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C'mon Phil, stop with the "B&S". Just always use the metric "mm2" which is sensible and universal to the rest of the world. Leave those Yanks to just stew in their own parochial dogma.

Gday Allan,
Cable size is very hard to express on forums!!

It is impossible to type "millimetre squared" in an abbreviated form because this forum doesn't allow superscript.
Some people type mm2 which is not correct.
Others type mmsq which is a bit better.
Others think mm2 or mmsq is the same as mm and think 6mm auto is the same as 6 B&S
Others think 6mm auto cable is the diameter including the insulation - its not - because 6mm auto measures 4.5mm diameter and is about 4.5mmsq.
In any case the stuff I use is not 8mmsq, it is either 7.91 mmsq or 7.7mmsq!

Buy the cable from Jaycar and it will be 8AWG or 8Ga
Narva use 8B&S
Tycab use 8B&S
Lugs will be 8B&S
Tinned cable from Whitworths is 8B&S.

So when answering in forums, I use the measurement that is the least confusing to a general audience and which the shops use which is 8B&S!!

Cheers
Phil

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Yeah Phil, I know, I know, I know! Have you had chat with mate Donald lately? lol
I grew up with "inch" cable specs. e.g. '7/.029' meant 7 strands each 0.029 inches diameter.
Then Australia thankfully metricated and I converted to metric cable as "4mm2" e.g. Of course as superscript is not accepted here (and in any case, my keyboard does not offer it) I write mm2 which, rather surprisingly, everyone seems to understand as an alternate to the superscript.

Now, in any case, as I don't care what Narva, Tycab et al call it as I don't buy from them I continue to use the nomenclature standard of the Australian electrical industry which is "mm squared' and write "mm2".
And incidentally, Jaycar generally use "AWG" not "B&S". Sometimes adding "mm2 cross sectional area".

If I really must acquiesce to avoid serious confusion I may reluctantly specify "B&S", but I will never say "gauge" or some "auto size".
But if you say "B&S" I will understand what you intend even though I may be a pig-headed pedantic.

While we are at it, I say "kilo-metres", not "kill-LOM-eters" as I am following the official Australian standard.
Yes, there is one for metric pronunciation.... Google it.
I don't know where "kill-LOM-eters" came from as no-one says "kill-LOG-rams" or "kill-LODGE-ools" do they?
It's "kilo" dammit..... "KEELOH-metres"..... It means a thousand whatevers.

Nah, Donald ain't my mate - geeze he's got it all wrong lately! I'm guessing if you asked him what B&S stood for, he'd suggest something entirely different :-)
And we both agree that Jaycar uses AWG!

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Sorry Phil, I expressed that badly. I was not intending to infer that you had affinity to that bloke. I meant it in the same way as "Uncle Sam"....... USA.

And I guess that we are stuck (for the foreseeable future) with using American cable terminology simply because all the cable suppliers use that terminology. That AWG/B&S terminology is pretty stupid as not only is it "inverted" (increasing number = decreasing size) but also the numerical value is not even proportional. The Yanks have done some stupid things over the years!

So OK, I'll compromise. For public expression I will express it as "mm2" followed by "B&S" in parenthesis.( )

Ahhhh, the age old wire size debate.
Being an auto sparky I tend to think in probably the worst size format but you get used to what you use. BRAND becomes important because different brands lable different cross sectional size watever it comes close to, usually the one above if it falls between, so being familair with what you use is important.

Insulation heat rating is another thing that does not have to be displayed on automotive cable.

The most important difference is the amount of strands, more strands of a finer size makes it more flexable and lessens the diameter of the cable although it has the same crossectional size. An example is comparing common battery cable to weldflex, the same diameter cable excluding insulation will have a much higher crossectional rating and have a much higher throughput due to there being less air gaps between the strands so Alans old school sizing is probably the best.

Flexability is very important in anything that moves.
I worked on a site recently that used Exane cable and its 2B&S cable was only 3/4the overall diameter of what I was used to and took smaller lugs but performed just as well and was so easy to work with.

And just for those of you that are thinking jeez this is getting boring, 1 more thing.

When looking up specs to work out VD and stuff, be sure to use the tables from the correct manufacturer, there are many things that affect the resistance of copper cable. Much of it has been made from copper that has been recycled many times and cheap cable is cheap for a reason, dont compare it to a quality brand.
How do you know a good brand from a bad one? Ask someone that uses a lot of cable not someone that sells a lot. Does a sparts retailer know a good quality cable when they mainly sell short lengths to people that rarely ever use it, or would they be more likley to know which brand has the highest profit margin?

Only Boomers would get antsy about 'kill-LOM-eters'.

Or worse even, probably pre Boomers...

yes.
Thanks Ken

Is the rating on that cross section copper really for 50 amps or is it able to carry 50A ( with lots of voltage drop) and not quite catch fire? or maybe it will!

On the money, RMD.

Here's a great link to a useful discussion on cable sizing.

Toward the bottom it discusses the folly of amperage ratings for cables.

Ken,
Tycab rate their 6mm twin at 38 amps which sounds more like a reasonable rating.

Assuming your data is close to correct then at that voltage drop and current there would be just over 79 watts of heat being generated over the 5 metres.

Given that the compressor will only draw that much when close to its max pressure which wouldnt be long, it would probably serve the purpose for the average 6 tyres at 40 psi.

But this is a clasic example of how retailers take the piss.

The aus standard on the packaging refers to the insulation and has nothing to do with the electrical characteristics of the cable itself.

As RMD indicated earlier if this cable was pushed to 50 amps it would become dangerously hot in minutes and easily exceed the temp rating of its insulation in a short time after that.

thanks Cuppa

On the lighter side,
How come if someone mentions wire size it always triggers a several day long debate.
Air hose has been mentioned but is there a myriad of posts about sizing, capacity, brands and all the other properties of air hose that is just as relivant as wire but not bothered about?
Use too small an hose will force a wiring upgrade lol.