The 2018 edition of the NFPA 70E 120.5 added Exception No. 1 which NOW PERMITS the use of adequately rated permanently mounted test devices to verify the absence of voltage rather using a portable test meter as part of the process of establishing an electrically safe work condition.

There are many conditions that must be met such as be permanently mounted, listed and labeled etc. Advocates state that this may be safer since a worker does not need to use a portable test instrument and expose themselves to the electrical hazards. So here is this week’s question:

Does your company/clients use permanently mounted voltage presence/absence devices in your LOTO?
Yes
No
Not yet but thinking about it

Hi Jim

Here in Canada with CSA Z462 our TC decided that an adequately rated PESD could be used in conjunction or to compliment a verification for the absence of voltage with a portable test instrument. There has been some question and dialogue on "what does adequately rated mean"? Does this refer to the CAT ratings found with low voltage test instruments (IEC 61010). Nevertheless myself as en electrician, tend to be in favour of "on the door" type devices for certain tasks. For example when I hear of a company that has operators or production workers opening a cabinet to reset an overload relay, I am quick to advise that they have an electrician install reset buttons on the door of the cabinet so that the operator does not have to open the door. If the resetting is happening on a frequesnt basis (several times on a given shift) then there is something else perhaps going on. Anyways provided that the electrical worker can verrify the presence of voltage first and can verify the absence of voltage upon disconnecting, then they are a good device. This would not negate a phase to phase and phase to ground verification of the absence of voltage on 3 phase systems. (Test your tester and test before touch)

Finally as technology moves forward and standards like 70E and Z462 become more mainstream in the workplace, these devices will be the way of the future

Jim, we were asked about the use of these by one of our clients. After reviewing the device they were considering, I told them it looked like it might be a good choice. I'd be okay with these devices, but I'd still want to verify the absence of voltage with another voltage meter. I'd imagine most electricians would want to do the same thing if they were going to get into the device for maintenance. Never hurts to be sure.

Len and Bill, I agree, it may take some time (if at all) for people to be comfortable and get away from using a meter for final verification - The old "Trust but Verify" comes to mind. This was an interesting exception added and thought it might create a good conversation. I understand UL addressed these devices as well (hence the "listed and labeled" requirement. One of the manufacturers' of these devices visits the forum too so I imagine he may have a few comments somewhere along the line.

As stated in a previous post; we mount these devises where a technician can see them during diagnostic work. It’s a visual reminder that he has left the panel on and has not locked it back out.

The “adequately rated’ really boils down to an over voltage rating. The failure mode of a voltage indicator is a phase-to-ground or phase-to-phase short circuit, so a poorly designed voltage indicator circuitry puts an entire power distribution system at risk. A voltage indicator has to be hardwired between all three phases and ground to provide phase voltage indication. Therefore, the voltage indicator circuitry inherently provides a fault path between phases and ground through the device. This is why voltage testing instruments, or in this case a voltage indicator, should be surge tested for use in power distribution (CAT IV), motor control-distribution panels (CAT III) applications, which is part of the UL 61010-1 approval. A voltage indicator must be able to withstand 8000V impulse testing in order to receive a 600V CAT IV certification. Most voltage indication circuits would blow-up and never pass this stringent surge testing to carry a UL and CAT III/IV mark on the device. UL also requires more creepage distances between phases for CAT IV verses CAT III. Perhaps CAT IV should be the minimum for all PESDs to insure that voltage surges do not damage the device and create an unsafe or dangerous condition regardless of where it is installed?

This is an interesting topic, I am only aware of one such device that is currently being tested by some members of the element14 community https://www.element14.com/community/roadTestReviews/2566/l/VeriSafe-Panel-Mtd.-Voltage-Tester, the first review has turned up an interesting issue.

For me I have concerns over the installation methodologies I have seen, especially with regard to high current supplies that the wiring for the Voltage Absence Device just isn't rated to withstand under fault conditions.

I also like to know the actual voltage value I am measuring as induced voltages and sometimes return voltages are lower than the actual supply voltage but are dealt with in a different manner than a panel found to be energised from its source.

In the motor control centres I work on, I also have three points to test to prove the panel is completely dead, seems a lot to start installing multiple devices on every panel.

I can see then being useful for main incomers and busbars, as long as the fault protection is dealt with during installation.

Kind regards

Not sure if it is the same type of device but OSHA has a letter of interpretation on the use of installed LED voltage indicators used for verifying absence of voltage. I am attaching it here.

OHSA December 12, 2012 Letter of Interpretation (LOI)

For over a decade, thousands of users have deployed SafeSide® Permanent Electrical Safety Devices (PESDs)(http://www.pesd.com ) in order to reduce their risks in isolating electrical energy. This elegantly simple innovation greatly reduced the likelihood of workers exposure as they re-confirmed ‘zero voltage’ during absence of voltage testing. This December 12, 2012 OSHA Letter of Interpretation (LOI) addresses compliance questions around voltage indicating devices. The users of SafeSide® PESDs will appreciate that the context of the quoted statement on page 2, paragraph 11 of OSHA’s LOI taken from OSHA’s Compliance Directive “The Control of Hazardous Energy – Enforcement Policy and Inspection Procedures� (CPL 02-00-147 page 3-52) makes a strong statement about the benefits and need for visual verifications for reducing risks for workers when isolating electrical energy. Remember that compliance does not necessarily mean that a worker is exposed to the lowest possible risk. In summary, this letter restates that presence-of-voltage indicators cannot be the sole means for isolating electrical energy in Lockout/Tagout (LOTO). Key points:

REM Safety Consultants drafted this for a large pulp and paper company answering the question: “how does an authorized employee verify that an electrically safe work condition exists without exposing himself/herself to the electrical hazards inside the energy control device?"

This letter is not specific to Grace SafeSide® voltage indicators even though many of us know that this pulp & paper company uses SafeSide® voltage indicators in their LOTO in most of their plants. The REM Safety Consultants letters has no reference to Grace SafeSide® indicators. OSHA’s response uses a broad definition for “LED type indication unit�, which could apply to almost any non-labeled, non-listed, and sub-standard non-UL LED circuits--most of which would not survive long in an industrial environment.

OSHA did not call an “LED type indicating device� a test instrument. In this case the NFPA 70E 110.4(B) test instrument rating definition applies, which requires a minimum of a UL 61010-1 certification. At the time of this letter was released, no “LED type indicating device� on the market was ever certified to UL 61010-1. The Grace SafeSide® R-3W2 received a UL-61010-1 CAT III (1000V)/CAT IV (600V) certification just as this letter was released.

This letter simply restates the requirement for the “bump test� as well as “additional verifications� to insure a de-energized state as per 1910.147 and the “voltmeter test� as per 1910.333. The sentence quoted from OSHA Compliance Directive CPL 02-00-147 (paragraph.11 of the letter)
needs to be read in the context of the entire paragraph. Lastly, the letter simply restates the requirement for the “bump test� as well as “additional verifications� to insure a de-energized state as per 1910.147 and the “voltmeter test� as per 1910.333.

OSHA’s broad definition of an “LED-type indicating unit� applies to virtually any cheap-and-dirty voltage indicating circuit that meets these vague requirements of footnote 1. Imagine a facility putting an entire power distribution system at risk by installing non-labeled, non-listed, and sub-standard “LED-type indicating units� on their isolators, not to mention their liability if these devices were also deployed in LOTO. Here is a better definition:
• UL Certified for use on power distribution equipment with a minimum CAT III (1000V) & CAT IV (600V). A voltage presence indicator must be able to withstand 8000V impulse testing in order to receive a 600V CAT IV certification. Few voltage indication circuits would pass this stringent surge testing and be able to carry a UL and CAT III/IV mark on the device
• Permanently wired to each phase and ground, therefore not susceptible to damage, wrong settings, and human error like a portable voltmeter.
• Ability to indicate both AC and DC voltages simultaneously with high impedance redundant circuitry.
• Self-powered from the voltage source, thereby requiring no batteries or a power supply.
• Operate on wide voltage and frequency range from 14.5VAC/VDC to 750AC/1000VDC in 50/60/400 HZ

I have a complete write-up with the original request letters from REM Safety Consultants if anyone wants a PDF?

Here is the PDF of Grace Engineered Products response to the Dec 12 2012 LOI. It has both or the REM safety request letters included.

The exception requires an instrument verification on a known voltage source after verifying absence of voltage on the circuit in question. How do proponents propose this be accomplished? Switching of the test leads would introduce the possibility of a switching error.

There is a continued contention between the machine safety camp and the OSHA LOTO camp...machine safety standards have evolved to the point where in all likelihood they exceed OSHA's LOTO requirements but so far no one has managed to convince OSHA to go down a different path. 70E has clearly taken a step towards the machine safety camp and this is probably going to be well received in jurisdictions OTHER than OSHA.

But there are other ways to doing things.

IEEE 386 standard elbow connectors which are shielded medium voltage disconnects for underground and other types of medium voltage equipment are fully shielded so that it leaves no breaks in the equipment and thus no way to test for absence of voltage. So they include a capacitive tap which provides direct reading of voltage but only microamps of power, rendering it completely safe for testing.

Similarly Grace sells a resistive tap type of system for panels and we distribute it combined with the "LED light" thing as a single unit. The resistive taps allow voltage readings directly through the door (voltage is reduced by a few volts) but again current is so low that it won't meet the perception threshold. This makes it much safer to test for absence of voltage particularly before opening a door. Obviously it is true that it's not really a substitute for testing again elsewhere but consider a motor peckerhead using typical NEMA style motors where the motor leads are just pigtails. Splicing methods vary but the most common are wire nuts (not good practice by the way), lugs and bolted connections, insulated mechanical lugs, and split bolts. All of these require insulation and leave nothing in the peckerhead exposed so aside from stabbing through the insulation with the meter probes, there is no way to get a valid reading without stripping off insulation. This leaves the only safe place to test for absence of voltage at the starter or disconnect if there is a separate disconnect switch. In an IEC style peckerhead the situation is somewhat improved only because with a terminal block present, most connections are not insulated so completely that you can't get a reading.

Concerns about short circuit currents don't really apply...the resistance is too high to make it matter even under dead short (fault) conditions. Overvoltage requirements apply just as they would with any other equipment so it has to pass the same kind of overvoltage tests that the rest of the equipment has to pass. One of the biggest installation problems that I have seen though is that since the wiring is often say #14 lead wires, there is a tendency to simply stuff them into a terminal block with the power conductors...BAD idea. Can't even begin to describe how much of a NEC 110 type violation this is. There are ways to do it but that isn't one of them.

Hi..i am a new user here. I want to know does this refer to the CAT ratings found with low voltage test instruments. Nevertheless myself as en electrician, tend to be in favour of on the door type devices for certain tasks. For example when I hear of a company that has operators or production workers opening a cabinet to reset an overload relay, I am quick to advise that they have an electrician install reset buttons on the door of the cabinet so that the operator does not have to open the door.

The CAT references are to the ratings on like Digital Multimeters and such.