Detecting Medium or High Voltage Inside an Electrical Panel

<...Medium or High voltage...>

Please quantify. 'Low voltage' is anything below 1000V. A wide range of equipment is available.

What procedures are in place to prevent personnel from coming into contact with these voltages?

Hello again. Its quite right to request quantification. When i am talking about Medium Voltage, i am reffering to voltages higher than 1.000V and specifically voltages from 6kV to 21kV (reference to Greece and Balkans Power Electric Grids). Voltages Lower than 1.000V are considered to be Low Voltages. For measuring Low Voltage Loads we use instruments that have an insulation category CAT III-1000V and CAT IV-600V and the equipment we mostly use and you also send me in this link, its satisfactory. Sometimes though we must do some works and measure in Medium Voltage Panels. So i am asking if there is any equipment to prevent personnel from coming into contact with Medium Voltage (higher than 1.000V) and specifically with voltages between 6kV and 21kV. I hope to have answered your question and brigded the gap came up from mine! Hoping to some extra help for finding such equipment. Charalampos

http://en.wikipedia.org/wiki/Electrostatic_voltmeter

http://mitchellinstrument.com/category/advanced-non-contact-ac-voltage-testers/

Dear Haris Kal,

Guest provided a good link, but you will need one of these of the appropriate length, approved gloves in some instances, and an experienced operator, since these voltages carry a terrible penalty for mistakes as you have acknowledged in your question.

Regards, CJM

Hi Mr. Kalothetos,

If your electrical panel is supplied by a three phase system you could use a protection/fault detection relay, as presented in

http://www.cooperpower.com/Library/pdf/03046.pdf

or

http://www.macromatic.com/products/phase-monitor-relays.html

The idea is to test the insulation of each phase and of the null (if there is an insulated null). Dangerous tensions can appear only if the insulations are weakened.

Marius Balas (marius.balas@ieee.org)

The most important issue BEFORE getting into ANY panel is LOCK OUT-TAG OUT.

Any effort to work in a "hot" (especially over 1000V) panel is bordering on suicidal.

If there is NO other way, isolate ALL conductors and devices not involved with cloth made of neoprene-encapsulated fiberglass hung over the panel from the top and clamped to the isolating cover using fiberglass spring clamps (with fiberglass leaf springs formed to fit internally) so only device being serviced is exposed.

Then- test all exposed contacts to be sure that cables are de-energized. Also, in addition to wearing "rated gloves", be sure that you are in shoes with di-electric soles and/or stand on DRY multi-layer rubber sheeting. Also- BE SURE THAT THERE IS AT LEAST 60 INCHES (1.5 METERS) OF CLEAR AREA BEHIND YOU (NOT in front of the panel) to eliminate the risk of you becoming a conductor between a hot wire and a ground point) and to allow for falling back to extricate yourself in case of contact with a hot line.

Better planning eliminates the need for luck.

Thank you all for your answers! They were all very helpful to find what i need and also expand my knowlegde. Keep up the good work! Best regards to everybody. Charalampos