Beckman HV-211 High Voltage probe?

What I mean is this: suppose that I have a HV system, such as a charged capacitor bank, such that one side is grounded and another is charged at high voltage.

Suppose also that my body is grounded.

I can measure voltage in two ways:

1) Clip the alligator clip to ground and touch HV side with the pointy end of the probe 2) Clip the alligator clip to HV side and touch the ground with HV probe.

Clearly, 2) is dangerous since my hand, holding the alligator probe, would be almost touching the HV side.

Whereas 1) is not dangerous, as far as I can tell.

If so, then, this probe can be used on HV systems where one side is grounded, in only one way.

This all may sound obvious, but I want top be very redundant in making sure that I use it properly.

i

You should run with the cases at a low potential (ground), connect the "hot" end of the probe to the HC terminal on the cap, the alligator clip to the case of the caps, and the other ends to your meter, with the meter set to the right voltage scale.

Most important: Once you have made all of these connections, do NOT touch anything (including the probe OR meter) while there's high voltage on the caps. Do NOT manually "probe" the caps while they are charged. A failure in the high voltage resistor can lead to some nasty problems - and you don't want to be near (or part of) the discharge path if this should occur... =

Making sure nobody else will touch it. I make sure all helpers in HV projects can shut things down themselves without needing help.

And the insulation on the alligator clip is nowhere near good enough to hold off 22 KV, which can jump an inch in dry air.

Approach 2 is more than dangerous, it's sure to kill.

Yes. The alligator clip goes to ground (~earth). Period. But make it _solid_.

The problem with probing is that one's hand can slip. With a TV tube, the stored energy probably won't kill. A 1 mike, 22KV capacitor is quite another thing. There are no second chances, even for cats.

I would wire things up with no HV, then creep the power up with a variac and see how it goes, without touching anything, then disconnect power and walk away for an hour.

Joe Gwinn