This may cause a stir here, but having two ground or ungrounded components
is a really bad idea, unless certain conditions are met.
Neon sign transormers MUST be earth grounded, period. Do not cut off the
ground lead or leave the case floating, ever. It's a safety hazard and any
inbalances in voltage will destroy the transormer. The insulation is not
rated to more than 1/2 nameplate voltage. If the case is floating (and it
will never truly float) one leg of the secondary will be overstressed.
Plus you have a big metal box at unknown potential. Basic electrical
safety should not be ignored if one is doing smart stuff like making tesla
coils. Ohm's law doesn't care about your intentions, or experience.
If you don't have a separate ground for RF use nearby, connect the lower
part of the secondary to your powerline ground. Add fancy ground planes if
you want to that. The primary coil is never isolated from your powerline
ground so it's always a shock hazard, period. If you get arcing between
the primary and secondary, you now have high and dangerous voltages
present everwhere. You can get one hell of a shock off a capacitor bank.
I have only disconnected the secondary ground terminal at the bottom from
the ground IF it can be connected to a "better" ground nearby. That is if
there's a cold water pipe going into the ground nearby, I'll ground the
secondary there, everything elses uses the powerline ground. You do not
want to create a ground loop by connecting the two if they already are
bonded (as they should be) at the service panel.
Granted, tesla coil fatalities are probably close to zero, but any dumb
accidents you can have with one were going to be preventable. Things to
consider
-is there a safe way to turn the thing on an off? I like foot pedals or
pushbotton switches you have to hold.
-where are line voltages present? Where can they cross into?
-where can these voltage end up? What if your secondary falls over on the
primary onto you?
It's not all doom and gloom, but one should not go out out of the way to
create more hazards than necessary.
On Sun, 21 Nov 2021, Joshua Thomas wrote:
> This is actually all I?m able to use because of my living scenario. When
> I?m not able to get physical earth access, I?ve been having to use a large
> (24? x 24?) Al sheet as a counterpoise. Part of the challenge of coiling in
> limited space.
>
>
>
> On Sun, Nov 21, 2021 at 7:00 PM Chris Reeland <chrisreeland@xxxxxxxxx>
> wrote:
>
>> Hi all,
>>
>> I looked back at some of his original specs. to get up to speed on this
>> again.
>>
>> This to me looks possibly iffy:
>>
>> " * RF grounding rod of 1 ft, solid 1" copper, with 14 ga connection wire.
>> "
>>
>> Would definitely change secondary behavior if it is insufficient... being
>> just a foot long rod, which I am sure is less because of what sticks up for
>> wire connection and all the other variables of the actual soil/earth
>> conditions.
>> Just a possible thought here of one of several problems that seems to be
>> going on from my view point currently. Still debating on the others. Will
>> wait on them for now.
>>
>> Chris Reeland
>> Ladd Illinois USA
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> --
> Joshua Thomas
>
> My new email address is: joshuafthomas@xxxxxxxxx
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