View Full Version : Fusing an Additional Socket

Matt (WA)
28-09-2007, 08:43 AM
Should/Do you need to Fuse an additional accessory socket that’s sole purpose will be to run a 40l Engel…… :roll: I plan to run it straight off the Aux Battery.

28-09-2007, 09:18 AM

28-09-2007, 09:56 AM
Leachy, someone should have a go at you for being so verbose in your posts :lol: :lol: :lol:

... but totally agree.

Just as a matter of course I fuse everything, taking even more care where wiring runs the length of the body. 4WD's bounce, move, twist etc, wires chaffe, fires start oooppss ! :oops:


Matt (WA)
28-09-2007, 10:26 AM
Thanks Guys,
Any particular type? I was thinking of an auto reset one.

28-09-2007, 10:36 AM

My preference is to use fuses rather than auto reset circuit beakers.
If a fault occurs in the wiring protected by a fuse it is made safe by the action of the fuse until you take action to rectify the fault and replace the fuse. Whereas with a auto reset CB you may be unaware that a fault has occured (it's not always immediately obvious that the fridge has stopped working) and the CB will keep on reclosing the circuit, hiding the problem and possibly causes greate damage.


28-09-2007, 11:06 AM
Agreed. Some applications - such as an electric brake controller - specify an autoreset CB, but for all other applications I use fuses.

Same reasons as Leachy mentioned. If a fuse blows there could be a short. If I replace the fuse and it blows again there is a short and I know I have to track it down.

A CB will disguise this and may cause you to suspect a faulty device (at best) or a meltdown.


Matt (WA)
28-09-2007, 11:11 AM
Thanks for the Advice Gents much appreciated.

28-09-2007, 11:47 AM
The advice from Leachy and chippy is 100% correct Matt.

28-09-2007, 12:56 PM

That's one beautiful looking ride Matt.


Matt (WA)
28-09-2007, 01:19 PM
Cheers Chippy,
I have a few more things to do to her yet but we'll get there when the money tree Re-Grows........ :lol:

28-09-2007, 02:06 PM
For all you guys doing your own wiring installations, install your fuses as close to the battery as you can. This helps prevent fires when a short circuit is caused by chaffed wiring between the fuse and the battery. The shorter that distance is, the more likely you are that the fuse will protect the circuit. Also If you are running a Fuse block (say at the rear of the vehicle), make sure the wiring from the Battery to the Fuse block is also fused at the battery (With an appropriately rated fuse to handle the combined load). It may seem like common sense to most people but you would be surprised at the number of accessories that I have seen fitted where this approach has not been used. It is probably the cause of a significant amount of vehicle fires as well.

Matt (WA)
28-09-2007, 02:48 PM
Cheers Brissy4me,
I read in Previous Posts that the Fuses needed to be as close to the Battery as possible plus I have a Sparky Mate in the Street which helps too! :D

28-09-2007, 05:49 PM
What size fuse should you use?

02-10-2007, 10:42 AM
What size fuse should you use?

It depends on what wiring you use, which in turn is a function of what appliances you intend to run.
First step is to decide on the maximum demand and nature of the load that will be powered. Based on this you can select an appropriate wire size. At a minimum the wire must be sized carry the maximum expected current. Though in applications such as modern 12V refrigerators with low voltage cut outs it is very desirable to minimise the voltage drop in the circuit, so the wire selected may be larger than that required just to meet the current carrying requirements.
Once the wiring had been selected a fuse or circuit breaker can be chosen.
The function of the fuse or CB is to protect the wiring. By protecting the wiring from excessive current in overload or fault situations you prevent it from overheating, melting and catching fire.
The first criteria that must be considered when selecting the fuse/CB is that it must operate below the current rating of the wire used. Secondly the fuse/CB needs to be sized so that it does not operate under normal load conditions. The more generous you are with the wire selection the easier it is to find a fuse/CB that falls in between these criteria.
Personally I use 10mm2 with a 30Amp fuse to run my fridge. While this far exceeds the minimum needs and costs a little more, it ensures I get maximum voltage to the fridge and thus maximum performance.

Also pay attention to the points smeentioned by Brissy4me.


02-03-2008, 08:27 PM
I just came across this.. Sorry to dig it back up.

Just to add to this thread don't forget the rating of your outlets either. Make sure you don't fuse your supply higher than your plug rating. ie don't put a 30A fuse on a 10A cigar socket... Hella sockets are only rated to 20A also.

If you do and you start drawing more than the rating of the plug you'll end up with a melted mess in the back. :oops:

03-03-2008, 08:11 PM
I just bought a ABR sidewinder marine plug rated at 20amps. Can I run a 20 amp fuse with this plug ????


Yes mate absolutely. You've just got to make sure your cable size is adequate which I'm sure it is.

As per my previous post, don't fuse your outlets higher than their rating. By all means go lower just not higher.

Most fridge plugs also have fuses built into the plug so no need to worry about the fuse size on the outlet, unless of course it doesn't have a fuse. Confused? haha :D

I put the same plug in as you and also a "cigar" plug. I put a 20A fuse on the hella and a 10A fuse on the Cigar outlet. All as per their current ratings.

Also it's not ideal to put a CB on an outlet as it will keep closing onto a fault if you're not aware of what's going on. :D

Steve & Sandra
02-05-2008, 11:29 PM
Farmers are a good at this, they like to test the wiring by chucking on as many lights as possible. I have seen many melted wires on headers and tractors. some are brighter than small towns. A nightmare to fix sometimes.

07-05-2008, 07:27 AM
As some have suggested, everything should be fused!

I design and instal electrical systems from 66 000 volts down to millivolts - and everything is protected by fuses, circuit breakers, fusable links or the like. Only short runs of cable are allowed unprotected and must have substantial mechanical protection to prevent damage and short circuits.

If not, in the event of a short circuit, the cable becomes a fuse! Normal automotive cable can handle the short circuit capability of a battery for at least several seconds - and will get very hot in the process.

Melted wiring insulation and anything else near it will result. Not only is it a nightmare to sort out, but the last thing you want to be doing away from civilisation!