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Old December 2nd 05, 05:28 AM posted to rec.radio.amateur.boatanchors
Michael A. Terrell
 
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Default getting bit by my FT-101EE chassis

Ron wrote:

OK that is one case where your need two failures to cause a hot chassis.
Now for Doofus to get electrocuted he will also have to have one
hand on this deaf radio and one hand on the radio that has a metal
chassis that is plugged into a socket with a good ground. The problem
you could also have a similar problem even if the neutral was wired
correctly (not tied to ground). If the ground wire broke in the cord or
inside the radio and then a capacitor or a transformer had an internal
short to the chassis or there was a resistor from hot to chassis ground
then the chassis would become hot. The so called safety ground is not a
100% sure thing in the case of a failure. Because safety grounds are as
prone to fail as anything a third external wire tying all metal cabinet
radios together is the only safety measure if one has a table full of
these old AC powered beasts.

Yes it is not a good policy to tie the ground and neutral together. I
just felt that a good explanation of why not to do so was required
instead of just a blanket statement stating "The safety ground must
NEVER be connected to the neutral at the load !NEVER! "

But he on the safe side and ground those boatanchors together. (you can
buy a bigger boat that way).

Thanks
Ron WA0KDS


Ok, Ron here is another possible failure mode: The neutral from the
pole pig goes high resistance or completely open. if both halves of the
240 VAC service are not balanced and the imbalance will cause a current
to flow from the neutral wire, to the radio and back to the ground rod.
If that current is very high the cord will smoke or burn. I had to
replace a breaker box a few years ago after the neutral corroded to the
point it exploded. I was outside at three in the morning repairing the
damn thing to cool my bedroom down so i could go to work the next day,
but nothing had the suggested wiring, or I could have lost my home.
Also, you could have trouble collecting from your insurance company
after a fire caused by your own work.

--
?

Michael A. Terrell
Central Florida