fridge fuse

Submitted: Tuesday, Mar 02, 2004 at 20:40
ThreadID: 10952 Views:2154 Replies:8 FollowUps:14
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i was running the new ff 90 in the car for 2 days as a trial run before little desert , Today I noticed that it blew the fuse in the cigi lighter atachment that comes with the fridge , I am now worried that this might happen again , The wiring in the car is new , with 30 amp house grade wire and well insulated. I changed the fuse and its been working fine ever since . Has anyone had this problem before . I hope it was just one of those things and not a possible problem . The fridge is empty but i dont think that had anything to do with it and the setting was on 3 ,

My second question is , is there a diffrence between 12 volt and 24 volt fuses , or is it just 8 amps for both . The season I ask is that the fuse I replaced it with only specified 8 amp ( automotive fuse ) . I just want to make sure I replaiced it with the right one . The fuse housing recomended 8 amps , 32 volts ?Venus Bay
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Reply By: Wayne (NSW) - Tuesday, Mar 02, 2004 at 21:30

Tuesday, Mar 02, 2004 at 21:30
Eric,

Fridges work better when full. The fridge could have been working to hard trying to cool air. Try filling the fridge up with cans with some amber fluid in them. That is always a good test for a fridge.

If the fridge is 12v why would they say 8 amp, 32 volts. Stick to the 12 volt fuse.

WayneAlways Out'N About
AnswerID: 48941

Follow Up By: Member Eric - Tuesday, Mar 02, 2004 at 21:38

Tuesday, Mar 02, 2004 at 21:38
weaco fridges run on 24 or 12 volts , my ac aplication is 24 V, this is why I asked if there is a difrence in fuses , are 12 and 24 V fuses the same ?Venus Bay
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FollowupID: 310755

Reply By: Member - Eskimo - Tuesday, Mar 02, 2004 at 21:37

Tuesday, Mar 02, 2004 at 21:37
fuse's are consumables and are to protect the heart.
if it blows/ruptures once and continues to work satisfactory after a new has been replaced and it works ok then put it down to a "weak fuse"
they are known to rupture for no known reasons Wow, am I cute! The extra long legs are built-in prevention against ducks disease. Great looks and a real goer. Doesnt waddle along like some.
AnswerID: 48942

Follow Up By: Member Eric - Tuesday, Mar 02, 2004 at 21:40

Tuesday, Mar 02, 2004 at 21:40
Thanks eskimo , Its been working fine since i changed the fuse at 4 Pm today , Ill fill it with drinks tomorrow and see how it goes .Any idea on the fuse rating , question 2 ?Venus Bay
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FollowupID: 310756

Follow Up By: Member - Eskimo - Tuesday, Mar 02, 2004 at 21:50

Tuesday, Mar 02, 2004 at 21:50
eric,
once had a debate about 10amp/12 versus 10amp/240 volt

The conclusion:
the fuse blows at the same current draw in both instances ( and it is'nt any different at any other voltages)

I dont know what the rating should be but your manual should tell you what the fuse protection should be. This is generally the max fuse size! but could be varied by + 5amps if absolutely neccessary

Wow, am I cute! The extra long legs are built-in prevention against ducks disease. Great looks and a real goer. Doesnt waddle along like some.
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FollowupID: 310759

Follow Up By: Member - Eskimo - Tuesday, Mar 02, 2004 at 21:51

Tuesday, Mar 02, 2004 at 21:51
pick me up on the way to LD and i'll keeep your fridge going lol lolWow, am I cute! The extra long legs are built-in prevention against ducks disease. Great looks and a real goer. Doesnt waddle along like some.
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FollowupID: 310760

Reply By: The Publican - Tuesday, Mar 02, 2004 at 22:39

Tuesday, Mar 02, 2004 at 22:39
do yourself a favour and get rid of that junk cigarette lighter plug
get a 16mm din plug or clipsal T plug and use a 20 amp fuse
the fridge can take up to 12 amps to start when hot
30 amp house grade wire is c**p in a car
do the job properly
AnswerID: 48950

Follow Up By: The Publican - Tuesday, Mar 02, 2004 at 22:43

Tuesday, Mar 02, 2004 at 22:43
ff90 with large compressor requires 25 amp fuse
16mm din plug is not really sufficient for ff90 fridge
if you must use a 16mm din plug and socket make sure it is hella not the cheep chinese c**P
if you keep that cigarette lighter plug you will end up with a fire
direct wire is preferable or use clipsal T plug
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FollowupID: 310777

Follow Up By: Member Eric - Tuesday, Mar 02, 2004 at 22:53

Tuesday, Mar 02, 2004 at 22:53
I think thats a little extream isnt it ? Weaco supply something that wont work , I agree with possible bigger fuse . I will get a 12 amp tomorrow and see how it goes .

About the house grade wire , I was told that it was more efficent due to been less strands and thicker , was I misinformed ?

cheers
Venus Bay
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FollowupID: 310782

Follow Up By: The Publican - Tuesday, Mar 02, 2004 at 23:06

Tuesday, Mar 02, 2004 at 23:06
mate if Waeco had a choice they would supply a fridge with 2 bear wires and no c**p cigarette lighter plug as they cause so much problems
you need a fuse in DC twice the starting current
mate house wire is c**p in a car and breaks internally from vibration
house wire insulation is not suitable for a car
car wire has 90c flame retardant insulation and is harder than house wire
mate square area of wire is square area and number of strands mean nearly stuff all
technically more strands are better as the outside of the wire is where the power is conducted and more strands gives larger surface area which is better.
mate the guy who told you to use house wire in a car is a dummy
for your fridge you need 6mm2 twin sheathed auto wire with a 25 amp blade fuse
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FollowupID: 310785

Follow Up By: Member - Eskimo - Wednesday, Mar 03, 2004 at 08:39

Wednesday, Mar 03, 2004 at 08:39
I think what The Publican is trying to say is:
House wiring does not have enough strands and as such is prone to break at terminals/connection points in plugs etc. This can happen due to vibration but the incidence can get worse when subjected to man handling....

Cable size is important...Wow, am I cute! The extra long legs are built-in prevention against ducks disease. Great looks and a real goer. Doesnt waddle along like some.
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FollowupID: 310811

Reply By: Rosco - Bris. - Tuesday, Mar 02, 2004 at 23:39

Tuesday, Mar 02, 2004 at 23:39
Eric

Without going into all the bs. House wiring is designed to carry 240V AC, hence voltage drop due to resistance is not a major issue. Totally different situation to 12V DC. It is also nowhere as flexible due to limited strands. Give it the flick and go for 12V wiring cable ... IMHO the bigger the better .. within reason. Different type of insulation also.

Not an electrical genius by a country mile but I reckon it's not he right product.

CheersFidei defensor

Rosco
AnswerID: 48961

Follow Up By: Rosco - Bris. - Tuesday, Mar 02, 2004 at 23:51

Tuesday, Mar 02, 2004 at 23:51
Just had a flash back to senior physics.

V=iR hence with 240 V cable and 30 A capacity ...
240=30*R
R=240/30
=8 Ohms (I think)

12 V cable and 30 A capacity ...
12=30*R
R=12/30
=0.4 Ohms (I think)

So would I be correct in saying you require much bigger cable in 12 V to safely carry 30 A current i.e. much less resistance.

I know there is a difference between AC and DC but the principle is more or less the same.

I may well stand corrected though .... and most probably will be.

.... ;-DFidei defensor

Rosco
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FollowupID: 310792

Follow Up By: Member Eric - Wednesday, Mar 03, 2004 at 07:34

Wednesday, Mar 03, 2004 at 07:34
I think I need to explain myself a little better lol . The cable from battery to rear of car is , 400 amp battery cable , the house grade wire , is less than a meter long just to make the gigi lighter connection . Does this help ?Venus Bay
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FollowupID: 310804

Follow Up By: Rosco - Bris. - Wednesday, Mar 03, 2004 at 08:22

Wednesday, Mar 03, 2004 at 08:22
Cobber I reckon the same still applies. House cable has much higher resistance (20 times if my above sums are correct). Even with a short length the fridge requires whatever watts to run, so with much higher resistance many more amps will be drawn to achieve the result, hence blown fuse.

(i think)

Fidei defensor

Rosco
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FollowupID: 310809

Follow Up By: Member - Captain (WA) - Wednesday, Mar 03, 2004 at 14:44

Wednesday, Mar 03, 2004 at 14:44
There is no difference in the electrical resistance of AC or DC wire, its all down to the size of the wire (ie. 6.0mm2 cross sectional area) not the number of strands or size of individual strands. Copper wire has a resistance of 0.0000017241 ohm-cm (volume resistance at 20C)

Copper wire resistance is a function of cross-sectional area and say a 1.0mm2 cross sectional area (csa) wire is availble as either 1 strand of 1.13 dia or 32 strands 0.2 dia. Both have a csa of 1.0mm2 and both have a resistance of 0.019 ohms per metre and both are rated at 10 amps (for 12v dc).

AC wire is generally rated differently to automotive DC wire as AC wire has significantly longer cable runs compared to automotive DC wire. Remember, resistance is a function of distance and an automotive wire is rarely longer than 6 metres, unlike the 100's of metres in AC wire. AC wire also has twin insulation, unlike automotive DC wire which has single insulation. But a good automotive electrician will always put the dc wire in convoluted tubing to help protect it.

The 32 strand wire in the above example will be far more flexible than a single strand wire, but there is no electrical difference. Thicker individual strands generally suffer stress fatigue (vibration) and can lead to breaking. But a well supported thick strand wire will not simply break.

Also, crimping is favoured compared to soldering as a soldered joint is more prone to stress fatigue. However, the cheap crimping tools seen in discount stores give a poor crimp connection and you would often be better off soldering the connection. The proper crimping tool leaves an imprint of the connector size in the plastic cover, one easy way to tell if the proper crimping tool has been used.

In a nutshell, if wire of sufficient diameter has been used there is no pratical difference between AC or DC wire for 12V automotive use, apart from the ease of use of multi strand wire.

Cheers

Mark

(NOTE- do not apply this "general" advise to high voltage AC applications, insulator resistance becomes significant, amongst other factors).Nissan 2003 GU 3.0TD
Windsor Rapid Offroad
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FollowupID: 310850

Follow Up By: Nudenut - Wednesday, Mar 03, 2004 at 15:22

Wednesday, Mar 03, 2004 at 15:22
at last some one who knows what he is talking about has finally taken the time to spell it out correctly.

Tinned copper wire is better than plain copper though. It doesnt corrode ie doesnt get a tarnish which can increase resistance through a terminal which can increase voltage dropI am human ...I think?
Must be....make too many mistakes!
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FollowupID: 310858

Follow Up By: Member Eric - Wednesday, Mar 03, 2004 at 22:33

Wednesday, Mar 03, 2004 at 22:33
thanks captain , I think your on the moneyVenus Bay
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FollowupID: 310917

Reply By: Member - Wim (Bris) - Wednesday, Mar 03, 2004 at 08:21

Wednesday, Mar 03, 2004 at 08:21
Eric.
The Publican is correct in every respect.
Ditch the cig lighter & building wire.
High current draw through cig lighter plugs is a problem waiting to happen.

Regards

Old sparkyIs it tinea or has it just been too long since the last trip?
AnswerID: 48973

Reply By: Member - Raymond - Wednesday, Mar 03, 2004 at 08:26

Wednesday, Mar 03, 2004 at 08:26
Hi Eric.
Both waeco and engel fit cigarette lighter plugs as every car has them. Travelling around town on good roads and not used alot they are fine. Once on the road, the vibrations from gravel and dirt roads cause them to arc and heat up losing the connection and are the main cause of both fridges not working. Remove the plug and replace with hella plug and you will not have a problem.
Raywanderin' in retirement. victor 2010
AnswerID: 48974

Reply By: MickeyJ - Wednesday, Mar 03, 2004 at 15:19

Wednesday, Mar 03, 2004 at 15:19
My Waeco came with a combo cigarette lighter/Hella Plug. There is a red section on the end of the plug, which if you twist it comes off allowing the plug to fit perfectly into "hella" sockets. This has been problem free for me, and still allows the use of the cigarette lighter fitting if required (MY AC adapter has one).

I would not use household wire in a car. I would use 6MM automotive cable, you can get it with a tough double insulated sheath, and it looks like coaxial cable (the stuff you run to your CB antenna)

The voltage rating on the fuse is not as important as the current. The current limiting is what protects the wiring from burning out. Most fuses in cars are either the old inline or the new blade style fuses, and there are plenty of the old style ones used in 240 v appliances. Personally I wire everything up with waterproof blade holders to match the rest of the electrical in my car. The old tube style fuses sometimes just broke due to vibration or damage. Also the cheaper holders use to melt. (The same way that cigarette lighter plugs melt). This is because they rely on spring pressure to make the central contact. As it get warm the spring loses its tension, which reduces the contact which causes arcing which causes heat, which makes the spring weaker, and the arcing does not transmit power as well, and so it gets hotter, and pretty soon it either stops working, draws more current than it should, and or catches fire, usually all three in quick succession.

The Hella sockets avoid this as they grip on to the side of the central pin, meaning they do not lose contact with vibration or rely on a spring to hold them in contact.

AnswerID: 49017

Reply By: Member Eric - Wednesday, Mar 03, 2004 at 22:34

Wednesday, Mar 03, 2004 at 22:34
Thanks all for your imput , the fridge is running well still , I think it was just one of those things lol I will upgrade to the hella plug , anyone got a part number ?Venus Bay
AnswerID: 49059

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