[Healeys] Another con - fused question

Richard Ewald richard.ewald at gmail.com
Fri Jan 11 17:05:34 MST 2013


Sorry but  you said
>>The fuse does not protect anything downstream of the
fuse except the wire!
This is incorrect as I showed in my diagram, when correctly placed this is
an incorrect statement.  Any and all components downstream from the fuse
are protected.  If we take your statement and change the word from wire to
component(s) it would be a correct statement.

But what the hell do I know, I just taught this stuff for about 20 years
and edited the electrical fault tracing course manual for a major car
company.
:::shrug:::


On Fri, Jan 11, 2013 at 3:50 PM, Bob <robertlarson at att.net> wrote:

>  Hi Richard,
>
>                  Been away from this for a few days.
>
>                  I will stand by my comments too.
>
>                  The fact that the fuse blows is indicative of an overload
> condition.  It acts as a safety to prevent damage to the wire or wiring.
> You are correct in your example that the switch may be protected.  However
> that is incidental to the fuse's primary function.   Best practices place
> the fuse as close to the current source as possible.  All is subject to
> Kirchoff's 1st or current law.
>
> Bob
> 55BN1
>
>
> On 1/2/2013 2:56 PM, Richard Ewald wrote:
>
> You and Robert are both wrong.
> Picture the two following circuits
> Batt---------switch----------X--fuse----light bulb--gnd
> wire rubs to ground at point X. The switch and wiring upstream of the
> failure will burn out due to the excess current running through it.  it is
> not protected by the fuse.
> Now look at this circuit
> Batt---fuse----switch---X----light bulb---gnd.
> failure is in the same place, point X.  Only this time the switch and the
> wiring is protected by the fuse blowing before the switch is damaged.  The
> switch and wiring is protected by the fuse.
> I stand by my comments.
>
>
>
> On Tue, Jan 1, 2013 at 1:07 PM, Bob <robertlarson at att.net> wrote:
>
>> Conceptually this concept is flawed.   The fuse does not protect anything
>> downstream of the
>> fuse except the wire!


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