Fuse Vs Circuit Breaker

[mouce]

Okay, fairly simple question: for a 100A cable run, which would be better to use? I know that circuit breakers aren't as 'instant' as fuses, but is there any real reason why one is better than the other?

[StoneX]

Circuit breakers are more instant... They will trip as soon as their current limit is reached, fuses have a bit of a delay. So they might be ok on their current limit for 1 seconds so quick bursts of current draw are ok, but the cct breaker would trip everytime.

Also, I think cct breakers could wear out over time... A fuse is always a fuse, it can't accidently conduct too much current if it goes faulty. Cct breakers might have a safety fuse for that reason, but i'm not sure.

[Tasmaniak]

actually Stone, the circuit breaker generally found in car audio ( the black one with a red switch and breaker button) doesn't for approx 4 seconds once load has been reached. TO trip instantly you need to reach 150% of it's load.

[dephilile]

100A fuses are expensive. Go the circuit breaker.

[mouce]

Here's the breaker I was thinking of (gotta love Jaycar)

http://www.jaycar.com.au/productView...Max=&SUBCATID=

[matrix]

ive got one of those breakers. they come in real handy when you want to work on your stereo, just press the button and "hay presto" no power to blow things up with.
i tripped mine once when i turned my sub up way too high. good thing was, i didnt have to go and replce anything i just reset the switch.

[StoneX]

That is another thing I don't like... If you have a problem, it will trip which might protect an amp or something, then the user goes and resets it and risks damaging something. If you have to replace a fuse, you usually think what could have caused the problem in the time it takes to organise a new fuse.

Anyway, never blown a fuse so it hasn't cost me a cent extra

[mouce]

I'm a bit of an electrical 'tinkerer' so if anything like that goes pop, I usually whip out the multimeter and test EVERYTHING that has anything to do with the circuit.

One thing though, it's going to be a fairly chunky cable that gets attached to it, and it's only got 5mm terminals. I take it a lug on the end of the cable will be okay for that?

[Tasmaniak]

I'm with StoneX. Go the fuse. A 100 amper costs no more then a 60 amper of the same configuration. besides, you have to haver seriouis issues if you blow that fuse. I've seen a couple blown ones but never blown one myself...except for that cavalier but that was a whole different story.

[1991_Vn2nV]

i have an aerpro fusebreaker in my car, comes in handy and looks good under the bonnet with a blue led when power is on and a built in voltmeter with red led's. Looks great. Any motoquipe store will get them in for you, or for that matter any Aerpro dealer.

[jds303]

a fuse rating is what current the fuse can pass, not necessarily what it will blow at. fuses can handle 2 to 3 times the rated current instantaneously before they blow. circuit breakers are good, but come in limited amperages, however will trip just like 12volt said. fuses however, are cheap, and come in heaps more values. breakers you shouldn't need to replace if you trip them. i personally prefer fuses. either will work tho.

[mouce]

^^^That maybe true of slow blow fuses, but quick blow fuses will die straight away. And as for fuses being cheap, I think you and I have a different definition of cheap. Good quality ANL fuses at 100A, are not what I'd call cheap.

Anyway, you don't need to replace a circuit breaker if it trips. Just gotta test everything and then reset it after you fix what went wrong.

[garfa]

^^^That maybe true of slow blow fuses, but quick blow fuses will die straight away. And as for fuses being cheap, I think you and I have a different definition of cheap. Good quality ANL fuses at 100A, are not what I'd call cheap.

Anyway, you don't need to replace a circuit breaker if it trips. Just gotta test everything and then reset it after you fix what went wrong.

anl fuse upto 200amps = $10.
cheap.

[mouce]

Yeah, and I'm a poor uni student who earns SFA each week and is desperately trying to save for insurance which is due soon, not to mention petrol!

I know that $10 might not sound like much, and in all fairness it's not heaps, but at the moment...it's more than I've got to spare.

[garfa]

true, but normally people dont blow fuses.
just as a side note: i saw the biggest fuse i have come across a couple of days ago. say it handles 415v @315amp (~130kw). it was a couple of incles long and as big as your wrist! it was from an industrial sub station and it was from one of the phases on the 3 phase power.

[Tasmaniak]

Mouce, that I look at it is the cost of ONE fuse. You shouldn't need anymore then one fuse. Fuse Holder VS. the cost of a circuit breaker.

[1991_Vn2nV]

Circuit breakers are so much more convenient though. instead of disconnecting the battery terminal and shit when u need to do anything to the sound system, its just a flick of a switch. So easy! And they look better.

[StoneX]

I've heard circuit breakers wear out over time and won't operate properly, so i'll stick to the trusty old fuse

[mouce]

Thanks for all the replies guys, I've decided that it's going to be a fuse after all. I've just picked up a nice little inverter (500W pure sine wave from Jaycar) which will go in the boot so that's going to mean that a circuit breaker is going to be WAY more expensive than a fuse that's going to do the same job.

[RVN 355]

The 2 protection methods being a circuit breaker and fuse both have there advantages.- hrc fuse high rupturing capacity can handle high voltage so dont get me wrong fuses are good ie used in every home.

Remember that a protection device only protects cables not earth leakage unlike a RCD (safety switch). They are made to carry rated current ie 16A for a.c 50hz 230v tho designed to handle fault currents aswell. They are equiped to handle inttermitted loads for short times and trip in designated requirments of disconnection time so in that aspect they are better and more easier to manage and more cost effective than having to spend big dollars on fuse as some like the hrc are expensive.



Hope that gave you some understanding in my lingo

tho a circuit breaker with trip in the milli seconds can be intergrated as a MCB -RCD so there more , c/b come in 2 forms electrionic and mechanical

[RVN 355]

I've heard circuit breakers wear out over time and won't operate properly, so i'll stick to the trusty old fuse

circuit breakers yes to wear out as there are a set of contactors and relay which operate under fault conditions tho like any mechanical device that handles fault currents and trips under 0.4 second u expect wear and tear - there not too expensive for 6ka 16A or 10A normall a.c types. tho the rcd mcb single poles are more $