whats the go with 6mm wire.

Submitted: Saturday, Jan 31, 2004 at 21:53
ThreadID: 10166 Views:5421 Replies:8 FollowUps:8
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after reading heaps about needing 6 mm wire to run fridges ect .
after getting a 90 ltr weaco and trying it out last weekend and the lead not being big enough to reach the standard cigarette socket in the can i found a cheap and nasty extention lead(12volt)and had to use it to run the fridge.
now the question.this lead would be lucky if it was 2mm but still run the fridge like a dream why the importance of using 6mm wire.
i will be using 6mm to wire the fridge permanantly but didnt have a problem with 2mm.
only reason ill be using 6 mm is because it is what most people recomend .
but why
thank you for any imfo.
cheers due to duck season coming
ive decided to hide out
love jemima puddle duck
back after the season
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Reply By: hoyks - Saturday, Jan 31, 2004 at 22:00

Saturday, Jan 31, 2004 at 22:00
The main reason to use 6mm wire is to avoid voltage drop. The resistance in a wire that is of too narrow a creoo section could mean that although there is 12 to 14V at the battery (when the engine is running) there may only be 10V at the fridge. Result is that fridge wont work as advertised or may die totaly.

6mm wire is alot cheaper than a new fridge compressor.
AnswerID: 45003

Follow Up By: hoyks - Saturday, Jan 31, 2004 at 22:01

Saturday, Jan 31, 2004 at 22:01
That was cross section.

It's late.
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Reply By: Mad Dog Morgan (Geelong) - Saturday, Jan 31, 2004 at 22:41

Saturday, Jan 31, 2004 at 22:41
Here's the formula for voltage drop

Length of conductor in metres x current in amps x resistance of copper divided by the conductor cross section in sq mm.

The resistance of copper is 0.017

Remember the length of conductor not only includes the + cable but the earth return cable also.

6mm auto cable does not typically have a conductor of 6sq mm as this includes the insulation as well. There appears to be no standard, best to have a look at the writing on the roll or asking when purchasing.

So the question remains what is an acceptable voltage drop with these fridges...anyone know ? BEAM ME UP SCOTTY


Hooroo
Ray
AnswerID: 45006

Follow Up By: Brett - Sunday, Feb 01, 2004 at 17:44

Sunday, Feb 01, 2004 at 17:44
does the resistance of a power cable vary with the insulation type?
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Follow Up By: Mad Dog Morgan (Geelong) - Sunday, Feb 01, 2004 at 18:17

Sunday, Feb 01, 2004 at 18:17
I don't know Brad, if it does have any effect it would be so little as to be negligible I expect. If I remember correctly temperature has a small effect but 0.017 ohms/metre is the accepted figure. BEAM ME UP SCOTTY


Hooroo
Ray
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FollowupID: 307215

Follow Up By: Brett - Monday, Feb 02, 2004 at 18:17

Monday, Feb 02, 2004 at 18:17
I was being a bit pedantic. In my High Voltage days I think we needed to roughly know the lenght and insulation type and factor this into calculations to determine cable faults.

I agree, 0.017ohms per meter is more than accurate enough for the majority of calculations.
Thanks for the info Ray

Brett

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FollowupID: 307282

Reply By: Member - JohnR - Saturday, Jan 31, 2004 at 22:46

Saturday, Jan 31, 2004 at 22:46
Diamond the explaination above gives most of the answer. Electricity is like water in some ways- the more you want volume wise (amps) the bigger the pipe needed or you need more pressure (volts).

You could cause a fire of course if the wires got too hot because they are too small. Yes, a compressor is the other reason you may want to go bigger, especially if you get some hot conditions.

Jemima looks more like a sitting duck than one one would be interested in shooting.Regards

JohnR - Not enough of the right travelling, some here..... some over there.......
AnswerID: 45008

Reply By: John - Saturday, Jan 31, 2004 at 22:52

Saturday, Jan 31, 2004 at 22:52
Jim you coming tommorrow ?
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Follow Up By: Diamond(due to duck season) - Sunday, Feb 01, 2004 at 09:26

Sunday, Feb 01, 2004 at 09:26
gday john.
unfortunutly not.
we had a water pipe let go it the roof and have 1 big mess to clean.
next time for sure.
cheers
due to duck season coming
ive decided to hide out
love jemima puddle duck
back after the season
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FollowupID: 307166

Reply By: Member - Eric- Sunday, Feb 01, 2004 at 00:01

Sunday, Feb 01, 2004 at 00:01
First I need to say hello Jim , its been a while since we have spoken , second , looking forward to catching up @ little d . Third , do you mind telling how much your fridge cost , I know you always bag a bargan Venus Bay
AnswerID: 45013

Follow Up By: Truckster (Vic) - Sunday, Feb 01, 2004 at 00:16

Sunday, Feb 01, 2004 at 00:16
www.fridgeshop.com.au they have some dusty seconds there.

christ knows where Jims going to fit the flammin thing with his tribe.
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FollowupID: 307154

Follow Up By: Member - Eric- Sunday, Feb 01, 2004 at 00:24

Sunday, Feb 01, 2004 at 00:24
so were you off to in the next couple truckster . Might tage along on one of them Ideal week for me is the 14 and 15thVenus Bay
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FollowupID: 307156

Follow Up By: Diamond(due to duck season) - Sunday, Feb 01, 2004 at 09:30

Sunday, Feb 01, 2004 at 09:30
gday eric.
the fridge was from fridge shop.
cost me $960 delivered.
and boy its huge went away last weekend and could have packed twice as much in.but at least i got ice cream lol.
cheers and see you @lddue to duck season coming
ive decided to hide out
love jemima puddle duck
back after the season
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FollowupID: 307167

Reply By: David O - Sunday, Feb 01, 2004 at 18:00

Sunday, Feb 01, 2004 at 18:00
I learned the lesson the hard way- though my fridge is a Chescold three way which draws about 10.5 amps.

I had twin fles running the length of the car from the aux battery and could never get the fridge to work, simply woiuld not work. I also fried my alternator. I put in a new 85 amp alt and did a test. With the engine running and 13.5 volts at the battery, I had 10,4 volts at the fridge with the fridge on full cold.

I ran 6 mm wire, and the fridge works fine plus the voltage drop is less than 0.7 volts.
AnswerID: 45063

Reply By: chrisfrd - Sunday, Feb 01, 2004 at 18:54

Sunday, Feb 01, 2004 at 18:54
LOL!

I've got 25 sq mm welding cable front to back on my Nissan, from the aux battery to the main is the same too!

I only drop .2 of a volt front/back/side. Only problem is that my aux battery is next to the turbo, so it boils it's electrolyte off every month! Mongrel of a car!
AnswerID: 45071

Reply By: tim - Sunday, Feb 01, 2004 at 21:27

Sunday, Feb 01, 2004 at 21:27
Unless you have something that is drawing a lot of current like a chescold 10amps it would be ok to run 4mm wire.I have done this and have no problems at all, and dont forget to use a good plug and socket not a std cigarette one
AnswerID: 45096

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