I can't see where using a regular home circuit breaker in the car would
cause any problems, but I'm no circuit breaker expert (and I don't play one
on TV).

Any comments?

Thanks.

Bob

--
== NOTE: I automatically delete all Google Group posts due to uncontrolled
SPAM =

I can't see where using a regular home circuit breaker in the car would
cause any problems, but I'm no circuit breaker expert (and I don't play
one on TV).

Any comments?

I can't see where using a regular home circuit breaker in the car would
cause any problems, but I'm no circuit breaker expert (and I don't play one
on TV).

I can't see where using a regular home circuit breaker in the car would
cause any problems, but I'm no circuit breaker expert (and I don't play
one on TV).

Any comments?

On Thu, 1 May 2008 14:33:31 -0700 (PDT), gearhead <nospam@billburg.com
wrote:

On May 1, 9:40 am, "BobW" <nimby_NEEDS...@roadrunner.com> wrote:
I can't see where using a regular home circuit breaker in the car would
cause any problems, but I'm no circuit breaker expert (and I don't play one
on TV).

Any comments?

Thanks.

Bob

--
== NOTE: I automatically delete all Google Group posts due to uncontrolled
SPAM =

Taking a circuit breaker designed for AC and trying to use it for DC
of the same voltage may result in an arcing problem. Whereas AC will
extinguish itself in the zero crossing, DC will not.


But at TWELVE VOLTS, there will be NO arcing, dipshit!

Most switches, as well as most circuit breakers have ratings on them
for both AC and DC. A switch DC rating is always lower than the AC
rating. That differential as stated on most switches, will tell you the
likely differential for a breaker as well. Since a circuit breaker IS a
switch that self-operates if taken beyond a specific current flow..

How about you listen dipshit....

But at TWELVE VOLTS, there will be NO arcing, dipshit!

If dc doesn't arc, how come points wear out? How come the old solenoid
washers would burn up?

Oh yeah it arcs...

But at TWELVE VOLTS, there will be NO arcing, dipshit!

If dc doesn't arc, how come points wear out? How come the old solenoid
washers would burn up?

Oh yeah it arcs...

I don't know what the original poster's specific application is, but...
if it's for an automobile application, I'd certainly be concerned
about arc issues.

A car battery has a low enough impedance, and enough stored charge, to
deliver a *very* serious amount of energy in a very short time. After
all, that's what they're designed to do... deliver hundreds of amperes
to the starter.

I've heard quite a few stories about mechanics (professional and
home-car-owner) dropping a screwdriver or wrench across the exposed
terminals of a car or truck battery. It arcs, all right... it arcs
seriously enough to splatter the unwary mechanic with molten metal.
In some cases (according to the stories I've heard) the tool is
essentially destroyed - there's little of it left.

If the OP is planning to run a high-amperage cable from a vehicle
battery to a heavy load (an electric winch, or a neighborhood-annoying
Overkill Boom Stereo system), and is concerned about the possibility
that this cable might someday be shorted to the chassis... then I
think taking the possibility of arcing into account would be a very
good idea. Both the risk of arc-flash injury at the point of
grounding, and the possibility that the breaker might arc-over
internally and fail to interrupt the circuit promptly ought to be
considered.

Best to use a breaker where you can be *sure* that the contacts
open far enough to quench the worst possible arc-over in a
high-amperage event. A DC-rated breaker, used within its published
design limits, is probably the right thing to do.

--
Dave Platt <dplatt@radagast.org> AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Yes, Dave, a 12V winch is exactly the application. It's this one from
Harbor Freight:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=95912

It's all hooked up and working. I used 12' of 8awg cable from the battery,
through a GE THQP250 breaker.

The manual says it's got a 1.1hp motor, so with a 50A breaker, I won't be
able to pull 3000lbs (746W/hp). I only need to pull about 500lbs (worst
case).

On Thu, 1 May 2008 14:33:31 -0700 (PDT), gearhead <nospam@billburg.com
wrote:

On May 1, 9:40 am, "BobW" <nimby_NEEDS...@roadrunner.com> wrote:
I can't see where using a regular home circuit breaker in the car would
cause any problems, but I'm no circuit breaker expert (and I don't play one
on TV).

Any comments?

Thanks.

Bob

--
== NOTE: I automatically delete all Google Group posts due to uncontrolled
SPAM ==

Taking a circuit breaker designed for AC and trying to use it for DC
of the same voltage may result in an arcing problem. Whereas AC will
extinguish itself in the zero crossing, DC will not.


But at TWELVE VOLTS, there will be NO arcing, dipshit!

Most switches, as well as most circuit breakers have ratings on them
for both AC and DC. A switch DC rating is always lower than the AC
rating. That differential as stated on most switches, will tell you the
likely differential for a breaker as well. Since a circuit breaker IS a
switch that self-operates if taken beyond a specific current flow..

"BobW"

Yes, Dave, a 12V winch is exactly the application. It's this one from
Harbor Freight:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=95912

It's all hooked up and working. I used 12' of 8awg cable from the
battery, through a GE THQP250 breaker.

The manual says it's got a 1.1hp motor, so with a 50A breaker, I won't be
able to pull 3000lbs (746W/hp). I only need to pull about 500lbs (worst
case).


** That 12 V winch motor has a big current surge ( ie full stall current)
when you first apply voltage that may well trip a 50 amp domestic breaker.
Just depends what amperage the magnetic device kicks in.

Under heavy loads, the current draw will exceed 50 amps - so again it will
probably trip the breaker a few seconds.

A 100 amp rated breaker ( as mentioned in your first post) is just what
you may end up having to use..

BTW

I hope the cable drum locks up when the motor is not energised.

...... Phil

MassiveProng@thebarattheendoftheuniverse.org wrote:
On Thu, 1 May 2008 14:33:31 -0700 (PDT), gearhead <nospam@billburg.com
wrote:

On May 1, 9:40 am, "BobW" <nimby_NEEDS...@roadrunner.com> wrote:
I can't see where using a regular home circuit breaker in the car would
cause any problems, but I'm no circuit breaker expert (and I don't play
one
on TV).

Any comments?

Thanks.

Bob

--
== NOTE: I automatically delete all Google Group posts due to
uncontrolled
SPAM ==

Taking a circuit breaker designed for AC and trying to use it for DC
of the same voltage may result in an arcing problem. Whereas AC will
extinguish itself in the zero crossing, DC will not.


But at TWELVE VOLTS, there will be NO arcing, dipshit!

Most switches, as well as most circuit breakers have ratings on them
for both AC and DC. A switch DC rating is always lower than the AC
rating. That differential as stated on most switches, will tell you the
likely differential for a breaker as well. Since a circuit breaker IS a
switch that self-operates if taken beyond a specific current flow..

Don't high voltage breakers have higher series resistance than low voltage
ones? Something to do with the trip mechanism?

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