How do you use a HV voltage detector?

I have a question regarding the use of proximity voltage detectors for performing absence of hazardous energy level testing, particularly related to medium voltage systems.

While I have a fair amount of experience applying 70e requirements in industrial facility and factory environments operating at 480V and below, I am inexperienced on higher voltage industrial systems. I?m hoping some of you gurus of smart can help me out.

My understanding is that the use of proximity voltage detectors for performing safe-to-work voltage is strongly discouraged. There are just too many chances for false positives and - heaven forbid - false negatives with a proximity voltage detector; rather, a direct contact style voltmeter should normally be used to verify absence of voltage less than 50 volts before performing work.

I am presently working on a construction project where we are performing hands-on work on 25kV equipment and our normal 1000 volt rated Fluke multimeters are not suitable for zero-energy voltage testing at those levels.

We have been using a hotstick-mounted Salisbury high-voltage proximity detector as our sole means of verifying a circuit is deenergized before working on the circuit. This proximity detector is not rated to detect voltages below 240V, nor can it read DC voltages which might be present from polarized insulation, charged capacitors, etc. It has been suggested that we use the prox to verify the circuit is deenergized at less than 240 volts and then using a Fluke as the final safe-to-work check, however that approach makes me uncomfortable.

Simply applying a safety ground is not an option available to us either. Applying a safety ground would require donning of appropriate PPE levels. Unfortunately, the consultants who performed the arc-flash study labeled the equipment, ?DANGER! NO SAFE PPE EXISTS. ENERGIZED WORK PROHIBITED. No FR Category Found.?

I?ve been having a hard time finding a direct contact high voltage meter that can verify absence of voltage to less than 50 volts. What is the best practice in this situation?

1. Turn on the instrument.
Turn the switch clockwise. If the green LED fails to light up or if it lights up only weakly, replace the batteries.


2. Checking operation prior to use
Using an outlet or other power source that you know has a voltage, verify that the instrument is operating properly.

•    If the red LED lights up and the instrument beeps: The instrument is functioning properly.
•    If the LED gradually goes out and the instrument beeps faintly: Replace the batteries.
•    If the red LED does not light up and the instrument does not beep: The instrument may be malfunctioning.


3. Detecting voltage
Turn the instrument on, verify that the green LED lights up, and place the detector in contact with the object you wish to check.

•    If the red LED lights up and the instrument beeps: The wire is live.
•    If the green LED remains lit up: The wire is not live or is carrying a voltage of 70 V or less.

*The instrument’s maximum detector-to-ground voltage is 600 V AC. Do not use it to measure voltages in excess of that value.