FUSABLE LINKS

Submitted: Friday, Aug 25, 2006 at 12:50

ThreadID: 37100 Views:2364 Replies:7 FollowUps:4

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mule

Does anyone know where I can get fusable links to protect dual battey systems & accessories as I have no confidence in curcuit breakers

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Reply By: fatz - Friday, Aug 25, 2006 at 13:28

Friday, Aug 25, 2006 at 13:28

www.naauto.biz

These guys should have all you want.

AnswerID: 190933

Reply By: Thylacine - Friday, Aug 25, 2006 at 13:38

Friday, Aug 25, 2006 at 13:38

Curious as to your lack of faith in breakers. Is there a reason?
They're a very reliable device.
Most applications where they 'cause problems' are only highlighting poor installations.

ed

AnswerID: 190936

Follow Up By: Member - Phil G (SA) - Friday, Aug 25, 2006 at 14:45

Friday, Aug 25, 2006 at 14:45

Ed,
Is there a reason all the vehicle manufacturers use fusible links and not circuit breakers?

FollowupID: 448650

Follow Up By: Thylacine - Friday, Aug 25, 2006 at 16:46

Friday, Aug 25, 2006 at 16:46

I'd suggest $ are the main factor (over logic) for manufactureres when it comes down to it, regardless of what they're designing.
But to answer your question, a fusible link is short-circuit protection.
Breakers are device protection.
A fusible link is more 'forgiving' than a breaker. They'll let past momentary surges that would trip a breaker. Personally, I'd prefer to be aware of increasing current draw in a circuit as it is generally an indicator of something about to fail.

ed

FollowupID: 448681

Reply By: mule - Friday, Aug 25, 2006 at 14:04

Friday, Aug 25, 2006 at 14:04

A bit wary of resettable circuit breakers in short circuit situations downstream of the battery & breaker, whether the breaker would just eventually melt down trying to reset itself from the amperage coming from the battery with it

AnswerID: 190938

Follow Up By: Thylacine - Friday, Aug 25, 2006 at 14:42

Friday, Aug 25, 2006 at 14:42

Shorts should be a *very* rare thing.
That being said, I don't agree with the use of auto-reset breakers in your average vehicle installation.
Get a standard breaker, and reset it manually if it trips. If it trips again, you're there and will notice. Good indication of a serious fault. And you can still fault-find.
If the link blows, any equipment down-stream is possibly already damaged and you're likely to replace the link and do more.
As stated, a short should not occur.
What is reasonably common is that a load will draw more current than 'normal' (usually on start-up) and if the breaker's rating is not suited to such a load, will trip.
If the breaker doesn't take into account such loading it's poorly chosen.

ed

FollowupID: 448644

Reply By: peteC - Friday, Aug 25, 2006 at 16:33

Friday, Aug 25, 2006 at 16:33

I just went to an auto electrician and he made one up to suit for $10

AnswerID: 190970

Reply By: Member - Phil G (SA) - Friday, Aug 25, 2006 at 19:08

Friday, Aug 25, 2006 at 19:08

Hi Mule (saw one in the Birdsville Museum last month!!)

I agree with you about circuit breakers.
Fusible links are the only sort of short circuit protection that you should use between dual batteries. The autoelectrician is the best suggestion - get them to cut a couple of short lengths and crimp some solid 8mm terminals. Then incorporate them into your wiring. As an alternative, you can get the Rotronics branded fusible links from 4x4 shops like Opposite Lock who deal in Rotronics.

The manual circuit breakers will trip in that application, which is not what you want. They also trip on corrugations, in my experience. The self resetting circuit breakers can also be unreliable.

For the wiring from your auxillary battery to your accessories, there are more options. My preference is to use another fusible link at the battery end (for short circuit protection), then run it to a fuse box (usually inside the cabin or canopy) to provide protection to the fridge, lights, or accessory sockets.

Second option I've used is to solder a blade fuse into the wire close to the battery. Most of the fuse holders these day seem to corrode with time, so I've found soldering them in to be a reliable solution. They never blow unless you short something out.

Cheers
phil

AnswerID: 190994

Reply By: Derek from Affordable Batteries & Radiators - Friday, Aug 25, 2006 at 20:33

Friday, Aug 25, 2006 at 20:33

Have you tried ABR ? ;-)

100 Amp Mega fuse

AnswerID: 191026

Follow Up By: Member - Phil G (SA) - Saturday, Aug 26, 2006 at 00:33

Saturday, Aug 26, 2006 at 00:33

Derek,

Is this what you are suggesting he put between his two batteries?

FollowupID: 448772

Reply By: Member - Mike DID - Friday, Aug 25, 2006 at 21:08

Friday, Aug 25, 2006 at 21:08

Most Auto Spares places will sell Fusible links up to 100 amps as spare parts. You may have to go to an Auto Elec to get the 9.5mm Spade Sockets that they plug into.

There are concerns about the miniature self-resetting Circuit Breakers but not the larger manual resetting Switches + Breakers. Altronics have the 70 Amp unit on special in September for $20.

AnswerID: 191042