Fridge wiring size help please!

Rusty Panels

Well-Known Member
Sorry, I may have misunderstood. I saw no mention anywhere of the fuse to the fridge which is what I guessed was the one in question.
 

Batts88

Well-Known Member
No worries. Some fridges have built in fuses into the main panel like my RF47 Evakool which Evakool replaced my 15amp fuse yrs ago with a 15amp resetable switch the also have a fuse built into the lighter plug on the power cord so double protection. I replaced the factory plug with an Anderson plug but still have a 2nd 15amp fuse protecting it .
 

MrMiller

Member
Just reviving an old thread instead of creating a new one...
Question on cables and fuses...
I’ve picked myself up a shiny new Dometic 55l fridge... looks to be the goods.
Going to clip the ciggie plug off the end of the power cable and replace with an Anderson.
What are suggestions on the fuse that’s housed in the ciggie plug itself?
I definitely want to fuse that run of cable as I’m no engineer and why mess with the professionals design.
Now do I wire in a glass fuse holder and use the 10amp glass fuse it came with?
Or alternatively just wire in a blade fuse holder with a 10 amp blade fuse?
Any major difference in running either type of fuse? I’ve heard that glass fuses take longer to blow while blade fuses blow quite quickly... I could be wrong as my source is definitely not a sparky...

Cheers all,
Brian
 

Swaggie

Moderator
Don’t use a cigarette plug to run your fridge.
Run at least 6mm2 wire from your battery to your fridge fused at the battery end.
Order Aussie cable also.

Goodluck
 

Baggs71

Active Member
Oops...wiring size question..my bad..yep agree..at least 6mm...id go 16mm to rear of car ...but thats being pedantic..6mm is fine..just be very careful of slight voltage drop over 5-6meters...you may see as much as .2 of a volt..does not seem like much but considering you have bought a dometic waeco there is a chance (seen first hand) if its a bluetooth blah blah model that it will suck amps like a two dollar hooker and will shut off sooner than expected due to slight voltage drop when you get a little low on amps left is fridge batt...leave nothing to chance...run a big wire to back and earth like crazy and put in good hardware like already stated....dont but cheap...or you will buy twice...enjoy the fitout!
 

red99td5

Active Member
Chances are that the tip of the cigarette plug on your current lead will unscrew revealing an Engel posifit plug.
You can buy from places like bcf an Engel fridge wiring kit which includes everything you need to run a fused cable from the start battery to the back of the car and an posifit socket.
 

boobook

Well-Known Member
Hi, I would personally go with the heavier wire option. As the previous replies said most electrical problems are faulty connections and in particular bad earths so unless you can ensure that your earths are spot on run twin cable.
The main reason for the heavier cable is that you may want to use that power source for other accessories at some point so, go bigger.
As far as fuses go the fuse is there to protect your equipment and wiring. If your fridge has a starting current of 10 amps then a 15 amp fuse will suffice. Check the manufacturers recommendation for the fuse. DON'T put too heavy a fuse in the line or you will cause catastrophic damage somewhere if a fault develops.
I'm sorry Gents if I sound like a Smart Alec but the mentions of 50 amp fuses in a few of the replies scare me a bit. You can't run fuses of that size safely in a vehicles accessory circuits. Things like winches and starter motors draw a lot of current which can be in the hundreds of amps depending on what it is but, generally the other gear like headlights, ignition systems, demisters etc might pull up to 20 amps for the initial start up but then drop back to around 10 amps or less once they're running. You won't normally find anything much larger than about a 20 or 30 amp fuse protecting those circuits. Like I said the fuse is there for protection of the circuit putting in a larger one just defeats the purpose and can be dangerous. Cheers.

Bingo.

My advice is to use the heaviest cable that fits and you can afford. You may want to run an inverter, lights etc later.

I ran 2B&S to the rear of my vehicle, for charging the camper, with a short length of 8B&S to the fridge / HF radio and accessories sockets. Some may say overkill but I'll never have to worry about voltage drop or running another cable.
 

Rusty Panels

Well-Known Member
Some of the reasons for 50amp fuses is for the main power supply from the starter battery to the aux battery which may be located under the bonnet or in the rear of the vehicle. Then all additional accessories will have their own fuses to suit.

Or from an aux battery which is mounted under the bonnet a heavy cable is run to a fuse box at the rear of the vehicle it has a larger fuse to protect that cable if damaged or overloaded you can put a fuse at either end if you desire but not necessary. Then each item run off the fuse box has it's own fuse to suit. Nothing wrong or unsafe with either set ups you may have missunderstood what some people were saying none of them are just using a single 50amp fuse to protect one item for eg their fridge.
I agree with your explanation but I think that some people (AKA the majority of do it yourself people) will not realise that individual items need smaller fuses in the line and may think that the 50 amp will be sufficient. Which is probably why I get myself into strife with my rants on some posts. I try to explain things as if I'm talking to a complete newb. Sorry if it is taken the wrong way.
 

Triton14

Well-Known Member
Bingo.

My advice is to use the heaviest cable that fits and you can afford. You may want to run an inverter, lights etc later.

I ran 2B&S to the rear of my vehicle, for charging the camper, with a short length of 8B&S to the fridge / HF radio and accessories sockets. Some may say overkill but I'll never have to worry about voltage drop or running another cable.

I ran 4B&S to the front of the rear tray with my set up when most people were saying 6B&S was enough(some were even saying 8B&S!).

Im like minded, over engineered might give you a bit more weight but gives you better security/integrity.

When someone tells me I have over engineered something I just respond by saying maybe you have under engineered yours!

12V wiring isn't something you want to skimp on, I've seen wiring insolation just melt in seconds when the wiring diameter is to small & there is to much resistance.
 

Colly18

Well-Known Member
.........................When someone tells me I have over engineered something................................
I figure there's nothing wrong with over-engineering something. I do it all the time and it gives me a warm fuzzy feeling! :)
 

Traveller

4x4 Earth Contributer
Just reviving an old thread instead of creating a new one...
Question on cables and fuses...
I’ve picked myself up a shiny new Dometic 55l fridge... looks to be the goods.
Going to clip the ciggie plug off the end of the power cable and replace with an Anderson.
What are suggestions on the fuse that’s housed in the ciggie plug itself?
I definitely want to fuse that run of cable as I’m no engineer and why mess with the professionals design.
Now do I wire in a glass fuse holder and use the 10amp glass fuse it came with?
Or alternatively just wire in a blade fuse holder with a 10 amp blade fuse?
Any major difference in running either type of fuse? I’ve heard that glass fuses take longer to blow while blade fuses blow quite quickly... I could be wrong as my source is definitely not a sparky...

Cheers all,
Brian

G'day Brian, once you cut the ciggie off and use anderson where is your power coming from? Ideally there would be a fuse close to the battery in the power lead to your fridge, you may not need another with the new plug- or I would solder in a wedge type fuse holder to the new plug-I'm not a sparky either, just like the pretty colours the wedge fuses come ino_O
 

MrMiller

Member
G'day Brian, once you cut the ciggie off and use anderson where is your power coming from? Ideally there would be a fuse close to the battery in the power lead to your fridge, you may not need another with the new plug- or I would solder in a wedge type fuse holder to the new plug-I'm not a sparky either, just like the pretty colours the wedge fuses come ino_O
I’m currently running a 100ah deep cycle under the bonnet. 3m run of 6mm twin core to an older waeco fridge outlet unit that has a ciggie and merit socket. 20 amp fuse at the battery. I’m removing the waeco outlet and replacing with an Anderson.

The main reason I want to fuse the fridge side of the plug is because there is a fuse already there housed in the ciggie plug. Keep the fuse there as it’s factory spec anyway so I’ll solder it in.

My only question was wether to use the glass fuse it came with, or a blade fuse and if there are any advantages to either.

Cheers
 

Baggs71

Active Member
Im not a spary but so long as you dont go over reccomended fuse rating...knock yourself out with an extra one...cant hurt
 

MrMiller

Member
Im not a spary but so long as you dont go over reccomended fuse rating...knock yourself out with an extra one...cant hurt
Yeah that’s my logic.
Dometic put it there for a reason, although I feel that’s to protect the fridge from dodgy wiring that may or may not be fused. Common sense isn’t really that common these days...
 

cookie64

4x4 Earth Contributer
So in the Electrical game there's a thing called the "coordination rule" which is what I consider, the golden rule. The load has to be less than the protection (fuse or circuit breaker) which has to be less then the cable size / current carrying capacity of the cable

AS3000:2018 2.5.3.1
IB </= IN </= IZ
where
IB = the current for which the circuit is designed, e.g. maximum demand (fridge etc)
IN = the nominal current of the protective device (fuse size)
IZ = the continuous current-carrying capacity of the conductor

I run a 10mm2 cable (Red & Black) from the front down to the back protected by a large fuse right nest to the battery positive, this then breaks down via smaller fuses to each outlet and is based on the typical load I will be drawing from the outlet, in my opinion, this provides maximum protection to the auxilliary power system and prevents taking out the main feed which in turn disrupts every other auxlliary load, the smaller fuse takes out that single load that has developed an issue and prevents an electrical fire.

I have found glass fuses not complementary to rigorous travel and use readily available Blade fuses which are readily identifiable by their colour as to the current rating, I use the covered type to minimise moisture getting to them. Most devices such as fridges do have fuses in the plug so be sure if you cut the plug off to use the same size fuse inline or on the outlet.


cheers
 

stevec064

New Member
Have enjoyed reading this thread, and have a simple (I hope) question along the same theme - If running 6B&S cable down to the back (Prado 150) with the intent to terminate at a 6 way fuse block - to run a fridge, a couple of cig points, USB etc - what lugs do you use to terminate at the fuse block? Asking as most fuse blocks I've seen only have a 4mm stud, and I can't find a cable lug that accepts the cable, and has a 4mm mounting hole. I'm still a novice at this, but I'm old enough to take whatever answers come my way. Thanks.
 

Albynsw

Well-Known Member
Have enjoyed reading this thread, and have a simple (I hope) question along the same theme - If running 6B&S cable down to the back (Prado 150) with the intent to terminate at a 6 way fuse block - to run a fridge, a couple of cig points, USB etc - what lugs do you use to terminate at the fuse block? Asking as most fuse blocks I've seen only have a 4mm stud, and I can't find a cable lug that accepts the cable, and has a 4mm mounting hole. I'm still a novice at this, but I'm old enough to take whatever answers come my way. Thanks.

What I do is maintain the main cable to the Anderson plug for the fridge but piggy back a smaller cable out of the back of that plug to feed the fuse block for your other smaller accessories
You want to maintain minimal connections between your battery and your fridge and not compromise the cable sizing in the process
 

CTL

Well-Known Member
Have enjoyed reading this thread, and have a simple (I hope) question along the same theme - If running 6B&S cable down to the back (Prado 150) with the intent to terminate at a 6 way fuse block - to run a fridge, a couple of cig points, USB etc - what lugs do you use to terminate at the fuse block? Asking as most fuse blocks I've seen only have a 4mm stud, and I can't find a cable lug that accepts the cable, and has a 4mm mounting hole. I'm still a novice at this, but I'm old enough to take whatever answers come my way. Thanks.

any size you want

 

stevec064

New Member
What I do is maintain the main cable to the Anderson plug for the fridge but piggy back a smaller cable out of the back of that plug to feed the fuse block for your other smaller accessories
You want to maintain minimal connections between your battery and your fridge and not compromise the cable sizing in the process
Thanks for that. Makes a lot of sense. Have seen pics of Anderson plugs with multiple cables but never gave a thought as to why. Need to sketch this all out I think.
 
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