Power fuse size

[WannaKatana]

I have two amps with 90 amps of fuses total. I'm told to put fuse of no
more than that near the battery but these ANL fuses do not seem to come
in 90 amps. Do I get 80 amp? Won't it blow often? I know I shouldn't
get 100 amps.`

Joel

[Kevin McMurtrie]

In article m>,
"WannaKatana" > wrote:

> I have two amps with 90 amps of fuses total. I'm told to put fuse of no
> more than that near the battery but these ANL fuses do not seem to come
> in 90 amps. Do I get 80 amp? Won't it blow often? I know I shouldn't
> get 100 amps.`
>
> Joel

The fuse at the battery is to protect the wiring, not the amps. The
amps have their own fuses. You can use a 120A fuse if all of the wiring
on that fuse can handle 120A. If the wiring is only good for 90A then
you better stick with 90A or less.

You may need to look online for fuses that large. If you get some
strange design, buy a few so you have spares. Make sure the fusible
part is enclosed. Some fusible links explode with molten metal and a
short burst of flame.

[MOSFET]

Why don't you look at circuit breakers? I use a 200 amp Phoenix gold
circuit breaker.

As well as being resettable (unlike fusses), they can be switched off when
you are working on the system.

MOSFET

"WannaKatana" > wrote in message
ps.com...
> I have two amps with 90 amps of fuses total. I'm told to put fuse of no
> more than that near the battery but these ANL fuses do not seem to come
> in 90 amps. Do I get 80 amp? Won't it blow often? I know I shouldn't
> get 100 amps.`
>
> Joel
>

[WannaKatana]

Kevin McMurtrie wrote:
>
> The fuse at the battery is to protect the wiring, not the amps.

Oh?? I thought it was just redundant protection and being close to the
battery would blow before the amp fuses. I used to read everything I
could find about car stereo years ago and never remember reading that.
I guess I need better sources.

> You can use a 120A fuse if all of the wiring
> on that fuse can handle 120A. If the wiring is only good for 90A then
> you better stick with 90A or less.
>
How do I tell what the max is for the wiring? Is that a spec given by
the manufacturer? based on size of the wire alone?

What I don't understand is, if the first fuse let's through 120A and
the amplifier fuse is less than that, wouldn't it be better to have the
same amperage at the battery? Wouldn't the amp fuse(s) blow also in
that case? Wow, I'm way behind in my knowledge (been out of car stereo
for quite a while and only then as a hobby, nothing serious)

Thanks for all the helpful replies.

[WannaKatana]

I didn't think of that. Thanks. Great idea.

MOSFET wrote:
> Why don't you look at circuit breakers? I use a 200 amp Phoenix gold
> circuit breaker.
>
> As well as being resettable (unlike fusses), they can be switched off when
> you are working on the system.
>
> MOSFET
>
> "WannaKatana" > wrote in message
> ps.com...
> > I have two amps with 90 amps of fuses total. I'm told to put fuse of no
> > more than that near the battery but these ANL fuses do not seem to come
> > in 90 amps. Do I get 80 amp? Won't it blow often? I know I shouldn't
> > get 100 amps.`
> >
> > Joel
> >

[Kevin McMurtrie]

In article om>,
"WannaKatana" > wrote:

> Kevin McMurtrie wrote:
> >
> > The fuse at the battery is to protect the wiring, not the amps.
>
> Oh?? I thought it was just redundant protection and being close to the
> battery would blow before the amp fuses. I used to read everything I
> could find about car stereo years ago and never remember reading that.
> I guess I need better sources.
>
> > You can use a 120A fuse if all of the wiring
> > on that fuse can handle 120A. If the wiring is only good for 90A then
> > you better stick with 90A or less.
> >
> How do I tell what the max is for the wiring? Is that a spec given by
> the manufacturer? based on size of the wire alone?
>
> What I don't understand is, if the first fuse let's through 120A and
> the amplifier fuse is less than that, wouldn't it be better to have the
> same amperage at the battery? Wouldn't the amp fuse(s) blow also in
> that case? Wow, I'm way behind in my knowledge (been out of car stereo
> for quite a while and only then as a hobby, nothing serious)
>
> Thanks for all the helpful replies.

You said your amps totaled 90A. They'd all have to short out at once to
blow a 90A fuse at the battery.

Fuses are fire protection, nothing more. They will not stop an
electronic circuit from frying because they're too slow. They blow
after a circuit has fried.

Some car audio cables have a current rating on the side. You can also
find recommended currents for different sized wires online. The gauge
of wire determines how much power is lost into heat. The insulation
type determines how much heat the wire can take before shorting against
something.