[Johnson] Ranger fuses

[SBJohnston at aol.com]

Kim writes:

> >But a short of the hot side to chassis would pop the hot
> >fuse, not the neutral one, wouldn't it?  
> In a word--NO.  When you fuse both sides of the line, you're very 
> likely to blow the neutral fuse, and leave the hot one intact.  

I'm not seeing how this can be.  We have a hot line that is 120 volts from 
both the neutral and the grounded chassis.  There is little or no voltage 
differential between the neutral and the chassis.  Suppose something fails to cause 
the hot lead to short to the chassis.  Why would the neutral fuse blow??  If 
anything, it would carry less current than usual, since some is going via the 
ground.  The hot lead, however, would definitely have high current.

OK, I'm going to set up an experiment to decide this point.  Stand-by a 
moment...  OK, here's the set-up on the bench right now:

I've got a three wire cord plugged into an outlet that has been confirmed to 
be wired correctly.  The hot and neutral wires of the cord are connected to 
the end terminals of a dual fuse holder.  The other ends of the dual fuse holder 
go to my 60w trouble-light as a load.   There are two identical 1.5 amp fuses 
in the fuseholder.

I will now cause a short of the hot side of the lamp to the grounded wire of 
the cord - this will simulate the short to chassis we are discussing - by 
touching a clip-lead from the hot wire going to the lamp to the green wire on the 
cord.  Stand-by...

OK, the lamp went out the moment I touched the clip-lead to both of the 
conductors.  When I inspected the fuses, I found the hot line fuse to be blown.  
The fuse in the neutral line is still good.   To eliminate the chance that there 
is something different about those two fuses, I'll get another pair from the 
drawer and try again.  Stand-by...

OK, did it again, same results.  The hot fuse blew.

Steve  WD8DAS

sbjohnston at aol.com