Microgripper maximum voltage

[ezalys]

So I have a collection of 206-0364-01 Tek Microgrippers. They have a maximum voltage of 40 volts written on the side. What exactly sets this? These little clips would be quite useful for looking at the voltage deep inside an older oscilloscope, but I don't want them to arc or melt. Is 40 volts the maximum voltage I should EVER use these to, or is it the maximum voltage it's safe to use while removing and placing the probes with my hands?

[David Hess]

I suspect that has to do with the insulation rating of the barrel part of the test clip which is only thinly insulated.  I would shrink some heat shrink tubing around it if used at a higher voltage.

[Jeroen3]

40V is common on test leads not specifically safety isolated. They’ll handle higher voltages fine, but you’re not covered by the manufacturers specification if it fails.

[Gyro]

The only probes I can remember with specific insulation breakdown issues were the original HP logic analyser ones which used anodized Aluminium barrels.

As Jeroen3 says, 40V is a generic rating for non shielded jack plugs etc. A bit of extra sleeving if the barrel is going to be touching other stuff and be mindful of what you're doing.


P.S.

... or is it the maximum voltage it's safe to use while removing and placing the probes with my hands?

It's the voltage where you should be seriously considering whether you are wise to be placing probes on the fly. 

[Zero999]

So I have a collection of 206-0364-01 Tek Microgrippers. They have a maximum voltage of 40 volts written on the side. What exactly sets this? These little clips would be quite useful for looking at the voltage deep inside an older oscilloscope, but I don't want them to arc or melt. Is 40 volts the maximum voltage I should EVER use these to, or is it the maximum voltage it's safe to use while removing and placing the probes with my hands?

Relax, under normal atmospheric pressure,  it's actually not possible for an arc to spontaneously form between two points, until the voltage exceeds 327V, which is higher than the peak voltage of 230V mains. An arc can from when the current is interrupted by separating a pair of electrical contacts, or when the mains voltage is higher than it should be.

The reason for the 40V rating is purely for insurance purposes. The insulation isn't mechanically strong enough to ensure it won't be damaged by moderate use and cause an electric shock. Don't hold the clips when they're connected to a hazardous voltage, which is typically above 60VDC or 25VAC.

[alm]

Some uninsulated Pomona clips have a rating of 40V, but up to 250V for hands-off use. So in that case, the rating is purely for human safety. As long as you make sure the circuit is de-energized before handling the clips, you can likely go higher. Just be mindful of shorting to adjacent parts.