Re: Scope grounding and generators

Glenn Little

For safety, the generator should be grounded to the single point utility ground for the building it will be providing power to.

The NEC probably requires this, I do not currently have access to a copy.
MIL-HDBK-419 (available on the web) addresses grounding.

Safety first.
Ensure all grounds are bonded together.


On 10/24/2020 11:49 PM, Chuck Harris wrote:
At issue is how the generator is internally connected, and
the possibilities of accidents.... and on whether or not you
are willing to bet your life that the generator is connected
the way you think it should be, and that it hasn't any faults.

For instance, you scope's ground wire is connected to earth
ground through the power cord.

Your generator should also be grounded, but if it isn't, an
accidental connection between the generator's hot lead and
the scope's ground, could cause the generator to be elevated
120V, or more, above the scope's front panel.

As I stated earlier, I use a filament transformer for such
measurements. Its fidelity is very good, and most are isolated
for several hundred volts... actually many of the older
filament transformers are good for 3000V.

-Chuck Harris

Robert Simpson via wrote:
Since I will not be connecting the generator to house power, I should be safe connecting house ground for my scope test. I want to see the shape of the power, the frequency and peak voltage. I think a scope will be my best tool for that. Besides, why have a scope if I don't use it whenever possible?

Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV AMSAT LM 2178
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"

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