phil2331 wrote:
This white paper (draft) covers the core LOTO issues in using permanently mounted electrical safety devices. Since many of you are using such devices, I would like to have your comments on this white paper.
Realistically, the biggest problem with capacitively coupled devices, or really any devices, is that you've got to quantify the probability of failure of them. So far I have not seen this done.
A great example is noncontact voltage testers that are used for voltage testing over 1000 volts. There ARE some "voltage meters" usually called phasing sticks that operate at those voltages and are "contact" voltage meters but they in no way work according to the same principles as a low voltage (1000 volts or less) multimeter. There ARE some capacitively coupled meters as well that measure using different principles such as a PD-50. These are very important for use on DC because none of the noncontact voltage meters can be used on DC or capacitors.
Anyways...just saying that there is already precedent for this in the world above 1 kV where there are simply no other options. Below 1000 volts though we see multimeters being the only acceptable alternative. There are arguments that noncontact meters are not acceptable because they are subject to both false negatives and positives, which is true REGARDLESS of the voltage.
I'd like to see something far more definitive on this subject which actually takes an objective look at the potential failure modes and risks involved in each. This is the only way that we are ever going to move beyond the world of portable multimeters being the only acceptable solution.