Q; What is OSHA's position on the use of a proximity detector to perform a live-dead-live verification for low voltage systems for an electrically safe work condition?
A: The short answer is you cannot use it for that purpose.
This question comes up frequently in electrical low voltage training classes. Most companies issue these devices for their employees to use to do trouble shooting on low voltage systems.
But the question is what OSHA’s position on these devices is. A formal request was sent to the Federal OSHA office to ask for a clarification. There were two responses. Each was very interesting.
E-Hazard is in Louisville, KY, and falls under Kentucky OSHA jurisdiction. The first response that came back was an email that stated the following:
Section 18 of the Occupational Safety and Health Act of 1970 encourages states to develop and operate their own state-run occupational safety and health programs. There are currently 22 states and jurisdictions operating complete State Plans (covering both the private sector and state and local government employees) and six states or jurisdictions – Connecticut, Illinois, Maine, New Jersey, New York and the Virgin Islands – which cover state and local government employees only. States must set occupational safety and health standards that are at least as effective as comparable federal standards.
Your state or jurisdiction runs a State Plan in Kentucky, and is not under federal OSHA jurisdiction, with limited exceptions. Your inquiry has been forwarded to your State Plan for response, and you should receive a response within 10 business days.
Most people may not be aware that their state falls under local state control and not under Federal control as noted in the above email response.
Then, as promised, about ten days later, I received a formal letter from OSHA . The highlight of their response is noted below:
OSHA does not specify the type of equipment to be used. You must meet 1910.333(b)(2)(iv)(B) as noted in the letter. NFPA 70E, that OSHA will reference under the general duty clause, requires verification of the absence of voltage when checking for an electrically safe work condition. Low voltage proximity detectors check for the presence of voltage, which is not the same as checking for the absence of voltage because they do not give out a “0 volts” reading and are prone to errors. (emphasis added)
So, the bottom line with the OSHA position is you must refer to your own state program and cannot use a low voltage proximity detector to perform a live-dead-live verification for the absence of voltage due to these limitations on the equipment and how it works. You must use a multimeter or a voltmeter rated for the proper voltage to be measured.
I have worked with Joe Rachford for 30 years at the former Inland Steel Company in East Chicago Indiana. I’ve known him for 50 years. There is not a better engineer anywhere to address issues just as this. Joe, is totally with it, with his well thought out, practical statements going a long, long way to straighten out the bureaucrats.
Excellent points Joe. It’s encouraging the Commonwealth of KY OSH, officially reminds us in their Letter of Interpretation that the General Duty Clause, under the OSH Act of 1970, will applies to NFPA 70E.
The other point I’d like to share, is for “low voltage” (600 volts or less OSHA or 1kV or less NFPA 70E), NFPA 70E, article 120.5(7) requires the absence of voltage test, to “test each phase conductor both phase-to-phase and phase-to-ground”. This means the test instrument must be capable of testing for electrical potential differences across two different points, which only a direct contact multi-meter can do. Non-contact capacitive testers are not capable of this, they can only test one point at a time for the presence of voltage.
For this reason Exception Number 2 of 7 under article 120.5(7), allows these non-contact capacitive devices to be used on high voltage system over 1kV and “to test each phase conductor”.