[Johnson] failure modes - and accidents

[Larry Rau]

god I hope we can bury this dead horse soon.
Lemme say at the outset that the good radio installation always  has these :

1. Proper circuit breaker to the outlet , proper fuse only in the hot lead
of the device, 3 wire grounded cord with ground to chassis ( but never the
neutral ! )   or at least a polarized plug, and a separate short RF ground
wire to an earth grund not part of the house wiring.

1. Accidents happen because of sequences of untoward events.
    ( go read FAA online accident reports.. to see this is alway true)

2.  We have discussed how a blown neutral fuse.. leaves the radio hot... ad
nauseum

Another problem is this :

Assume Nothing !
Not that your ground will keep working...it is spliced many times before it
gets to your shack.
Not that your neutral is grounded .
Not that your plug polarization is right.
Not that the fuse that came with the radio is correct.

Neutral in your main panel... is the center tap of  the "pole pig"
transformer on a power pole.
Supposedly it is grounded at the power pole by the utility company.
Also, it is required to be grounded at your MAIN panel ( where your meter
is) via a heavy ground wire and rod into the earth.

At your sub-panels - and anywhere else in your system... the neutral MUST
NOT BE TIED TO GROUND.
That is an electrical code requirement.

Now.... if for some reason ( remember the law of multiple failures or
sequential untoward events required for an accident)
            If for any reason... your neutral is not grounded ( gardener
cuts the ground wire outside in the bushes) .... then
 The Neutral Wire Is Potentialy Deadly ( pun intended) ..because it is
really now just  half of a 240 volt transformer winding.. floating above
ground potential !

There is no good point of a 120/240 volt ac source to contact... if you are
also in contact with ground !
No matter what you call it, or what color wire it is !

This is why we don't ground neutrals to a chassis, instead of using a real
ground !
This is why we dont fuse them.
This is why we don't assume a neutral is safe to contact, if the hot side is
disconnected !
(also why nobody in his right mind has an ac/dc radio in his system).

Larry W6WUH