I noticed that some car audio installers use a thin wire for ground while
they make you pay for a six guage power wire. This makes no sense to me.
Same current in power cable must run in ground cable right?

Correct, thats what I do...
Garrett


"Johan Wagener" wrote in message
...
I noticed that some car audio installers use a thin wire for ground while
they make you pay for a six guage power wire. This makes no sense to me.
Same current in power cable must run in ground cable right?

On Thu, 20 Nov 2003 19:23:36 +0200, "Johan Wagener"
wrote:

I noticed that some car audio installers use a thin wire for ground while
they make you pay for a six guage power wire. This makes no sense to me.
Same current in power cable must run in ground cable right?



you shouldnt use groundwire smaller then the power wire. BUT you can
use a bigger groundwire then the powerwire. I have had several
installers reccomand that to me. I think it is a better safe then
sorry thing.

wrote:

you shouldnt use groundwire smaller then the power wire. BUT you can
use a bigger groundwire then the powerwire.

That doesnt make any sense!

Since both the power wire and ground wire each carry the exact same current.
Both wires are equally important.

You just said you cant make your ground wire smaller than your power wire
BUT you can make you power wire smaller than your ground wire...
????
From a stand point of my statement above about them both handling the
exact same current, your statement makes no sense at all...

BUT!!!!
Neither one being larger than the other one is actually the issue!

The issue is that either one is adequate to carry the current you are
running through it...

Keep in mind (alot of folks forget this) that its not only the DIAMETER
of the wire that gives it the ability to carry alot of current but also its
length!

A long wire may have to be fatter
whereas a shorter wire may be able to be thinner!
(altough a fat one wont hurt)...

So, it might be possible for an adequate installation to have a super large
wire
coming all the way from the battery and a somewhat smaller wire could be
an adequate ground if shorter than the power wire...

As a installer, I would normally use BIGGER wire than I need and
make the ground and power both the same size...

But techicly speaking, whether one is bigger than another is not
an issue, the only issue is that BOTH wires are adequate for your
circuit....

good luck!

Eddie Runner
TeamROCS member #001
http://www.teamrocs.com

I noticed that some car audio installers use a thin wire for ground while
they make you pay for a six guage power wire. This makes no sense to me.
Same current in power cable must run in ground cable right?

If the ground is short, then it's not detrimental to use a smaller
gauge wire, as long as it can safely handle the amount of current that
will flow through it.

One other consideration is the amount of loop voltage drop you are willing
to accept in the power leads feeding your amp. A smaller wire even though
it can handle the current for the amp it may have a larger voltage drop than
a larger wire. Loop length of the wire is calculated as from the battery
and return to the battery.

A 20' loop length 10' from battery and 10' return to battery for a 20A feed
using 12Awg would have a voltage drop of 0.680VDC.
A 20' loop length 10' from battery and 10' return to battery for a 20A feed
using 10Awg would have a voltage drop of 0.428VDC.
A 20' loop length 10' from battery and 10' return to battery for a 20A feed
using 8Awg would have a voltage drop of 0.269VDC.
A 20' loop length 10' from battery and 10' return to battery for a 20A feed
using 6Awg would have a voltage drop of 0.169VDC.
A 20' loop length 10' from battery and 10' return to battery for a 20A feed
using 4Awg would have a voltage drop of 0.106VDC.





"Mark Zarella" wrote in message
om...
I noticed that some car audio installers use a thin wire for ground
while
they make you pay for a six guage power wire. This makes no sense to me.
Same current in power cable must run in ground cable right?

If the ground is short, then it's not detrimental to use a smaller
gauge wire, as long as it can safely handle the amount of current that
will flow through it.

You have to take into account length and the effect that has on total
path resistance... while it sounds good and doesn't hurt to specify same
gauge for both, the truth is a much shorter ground cable can work just
fine at a smaller gauge. Personally though, I would use the same or at
most no more than one gauge smaller.

JD

Johan Wagener wrote:

I noticed that some car audio installers use a thin wire for ground while
they make you pay for a six guage power wire. This makes no sense to me.
Same current in power cable must run in ground cable right?

For once I actually agree with everything Eddie said!




Paul Vina



"Eddie Runner" wrote in message
...
wrote:

you shouldnt use groundwire smaller then the power wire. BUT you can
use a bigger groundwire then the powerwire.

That doesnt make any sense!

Since both the power wire and ground wire each carry the exact same
current.
Both wires are equally important.

You just said you cant make your ground wire smaller than your power wire
BUT you can make you power wire smaller than your ground wire...
????
From a stand point of my statement above about them both handling the
exact same current, your statement makes no sense at all...

BUT!!!!
Neither one being larger than the other one is actually the issue!

The issue is that either one is adequate to carry the current you are
running through it...

Keep in mind (alot of folks forget this) that its not only the DIAMETER
of the wire that gives it the ability to carry alot of current but also
its
length!

A long wire may have to be fatter
whereas a shorter wire may be able to be thinner!
(altough a fat one wont hurt)...

So, it might be possible for an adequate installation to have a super
large
wire
coming all the way from the battery and a somewhat smaller wire could be
an adequate ground if shorter than the power wire...

As a installer, I would normally use BIGGER wire than I need and
make the ground and power both the same size...

But techicly speaking, whether one is bigger than another is not
an issue, the only issue is that BOTH wires are adequate for your
circuit....

good luck!

Eddie Runner
TeamROCS member #001
http://www.teamrocs.com

Mark,

That is definitely true but one should define "safe" as being not only
adequate gauge to allow the amp to develop its potential power properly,
but also large enough to avoid causing the amp to look for alternate
ground paths. When that happens, the amp may work more or less properly
but other components in the signal path can be damaged.

JD

Mark Zarella wrote:

I noticed that some car audio installers use a thin wire for ground while
they make you pay for a six guage power wire. This makes no sense to me.
Same current in power cable must run in ground cable right?



If the ground is short, then it's not detrimental to use a smaller
gauge wire, as long as it can safely handle the amount of current that
will flow through it.

One other consideration is the amount of loop voltage drop you are willing
to accept in the power leads feeding your amp. A smaller wire even though
it can handle the current for the amp it may have a larger voltage drop than
a larger wire. Loop length of the wire is calculated as from the battery
and return to the battery.

Um...we're talking about ground wires here, which presumably will be
quite short.

That is definitely true but one should define "safe" as being not only
adequate gauge to allow the amp to develop its potential power properly,
but also large enough to avoid causing the amp to look for alternate
ground paths. When that happens, the amp may work more or less properly
but other components in the signal path can be damaged.


Certainly. But which generally comes first? If your amp is seeking
alternate ground paths, then either something has gone awry (most
likely) or the wire is ridiculously small. If the ground wire is kept
short, then the "bottleneck" so to speak tends to be the connections
regardless of wire gauage.

That rings true from experience, but remember that it isn't always a
black and white (on/off) scenario, nor does it take much current passing
back up the RCA cable shield to toast a PCB trace in the source. If the
amp is getting hammered hard, and the power ground path has some
additional resistance, you can create a nice increase in current back
across the signal ground path.

JD

Mark Zarella wrote:

That is definitely true but one should define "safe" as being not
only adequate gauge to allow the amp to develop its potential power
properly, but also large enough to avoid causing the amp to look for
alternate ground paths. When that happens, the amp may work more or
less properly but other components in the signal path can be damaged.



Certainly. But which generally comes first? If your amp is seeking
alternate ground paths, then either something has gone awry (most
likely) or the wire is ridiculously small. If the ground wire is kept
short, then the "bottleneck" so to speak tends to be the connections
regardless of wire gauage.