I haven't seen anything posted on this so I'll ask it here. Has anyone used the "thru the door" voltage sensing? I see a lot published about it but have not used it myself. Also, do you feel this is a safe (acceptable) way to check for absence of voltage?

Thanks!

Yes, partly. Capacitive taps are common in medium voltage and the only practical way to check shielded conductors. The IEC standards recognize capacitive and resistive noncontact detectors, including fixed types such as various lights and abb visivolts that all work on field sensing and are field powered in some cases. The standards for under 1 kv require contact type voltmeters and require testing before and after testing so the grace stuff is useless.

So far Grace engineering has not got ieee or iec to accept their stuff, and neither has osha for proving absence of voltage. For general lockouts it would work but then so would almost anything else.

Thanks! Kind of what I was thinking. It's still a nice concept, hopefully it can get accepted down the road. For know I guess it just gives a warm fuzzy feeling before I use a contact VM as the ultimate check.

Keep in mind and I made this point in a submission to the 70E review process, UL (IEC) 61010 is most often referred to as the "meter standard". What you have in here are design/performance standards for meters of all types. The transient voltage test requirement is what gives us the "Category" rating on a meter (such as CAT III, 1000 V rating). What it definitely does NOT do is provide any standards for actually using the meter to test something such as testing for absence of voltage. 70E refers to this standard for voltage testing which is in error. UL 61010 properly belongs in only the section describing acceptable equipment for performing the test.

The only standard that I'm aware of for doing this activity is IEC 61243. There are several interrelated standards that give "contact" test methods for low voltage AC or DC (<1,000 volts), different test methods for noncontact testing above 1,000 volts, and permanent equipment-mounted passive voltage detectors such as "phase indicators", the ABB "Visivolt" product, and others that all operate off of field or busbar current and provide indication of voltage, but all the "substation mounted" equipment is again only for >1,000 volts.

Whatever standards there are I always recommend a live-dead-live test with a contact voltage testing device when possible. I have been an electrician and electrical supervisor for 45 years and this is the safest procedure I know.

We use some of these for lock out purposes and to give a good indication that voltage has been removed prior to opening the cabinet door. Always do a live-dead-live prior to actual work on potentially energized components.

There is a webinar sponsored by Plant Services on July 27th and the owner of Grace Engineered Products will be one of the presenters; typically there is time for Q&A at the end of these sessions.

So if interested, here’s the link:

http://reg.accelacomm.com/servlet/Frs.frs?Context=LOGENTRY&Source=source&Source_BC=32&Script=/LP/51550542/reg

It certainly got Eatons acceptannce who employ those as voltage absence verification in their UL approved arc resistant MCC's.

1910.333(b)(2)(iv)(B)
A qualified person shall use test equipment to test the circuit elements and electrical parts of equipment to which employees will be exposed and shall verify that the circuit elements and equipment parts are deenergized. The test shall also determine if any energized condition exists as a result of inadvertently induced voltage or unrelated voltage backfeed even though specific parts of the circuit have been deenergized and presumed to be safe. If the circuit to be tested is over 600 volts, nominal, the test equipment shall be checked for proper operation immediately after this test.

More detail in NFPA 70E (and even more in the handbook) without the voltage restriction.

Also note the disclaimer at the bottom of http://www.graceport.com/assets/files/Data%20Sheets/SafeSide_Thru-Panel%20VD%20Makes%20Sense_2013.pdf.

Disclaimer:


[SIZE=1][font=ArialNarrow][color=#081212][SIZE=1][font=ArialNarrow][color=#081212]Thru-panel voltage detectors are a supplement, not a substitute, for establishing electrically safe work[/color][/font][/size][/color][/font][/size]

conditions when working on potentially energized electrical conductors as per NFPA 70E 120.1(1)-(6),120.2(F)(2)(f)(3).
[color=#081212][SIZE=1][font=ArialNarrow][color=#081212][SIZE=1][font=ArialNarrow][color=#081212] [/color][/font][/size][/color][/font][/size][/color]

There are two levels of safety issue here. One is the removal of energy from a driven equipment, the second is the removal of potential from conductive parts. A third component is the ability to observe the voltage indicator directly before the disconnect operation is performed.

In my opinion a reasonable safety is provided for equipment lock out - first case - when the lndicator is observed and all 6 lights are present before and all 6 lights are 'extinguished' after the disconnect is operated and locked in the open position.

Shoud there be a necessity to work on conductive parts that need to be verified as 'live' or 'dead', I would perform the voltage test and tester verification before and after, on top of the verification lights. That is just me, I know that many people would feel absolutely safe relying on the indicator lights.

I think that since mechanical work is far more frequent than electrical so the indicator lights do serve an important function and aid.

Of course these are not the solution to all possible scenarios and voltages, but nobody claimed that. The key word, in all cases, is "qualified people" required to verify wheather the removal of power is assured or not.

There are 3 different cases to consider.

The first is for minor machine adjustment and similar activities. This is allowed using a variety of devices and can certainly include the stuff from Grace Engineering. Another version of this is a lockout system that Rockwell (AB) sells that disconnects power and pneumatic energy from a system with a huge variety of equipment designs and arrangements that meets up to I think around SIL 3. They specifically requested OSHA to bless it as a lockout system. OSHA responded that it is indeed good for that under Subchapter O, again being minor machine adjustment and similar activities. In fact just about any system works for this if it is safe enough to meet your risk assessment criteria.

The second is for general lockouts. In OSHA regulations, this falls under Subchapter J. In this case the key requirement is that the device used for lockout must be physically locked out and must physically block energy. This is where the guidance ends but gets very messy, very quickly. OSHA has been pretty clear that simply locking out control power is not sufficient. However, a visible break disconnect for instance is NOT required. This means that molded case breakers are sufficient for the task if they can be locked out. And it seems to imply MECHANICAL lockout. Where this gets ugly for instance is that frequently the lockout mechanism is some kind of linkage and that is what is being physically locked out as opposed to say inserting a spacer or some other physical barricade. The trouble I have with this definition is that a mechanical linkage is no different than an electrical one. I'd rather see a functional (provable reliablity) objective so that the available safety technologies could be brought to bear.

The third case is achieving an "electrically safe working condition", or Subchapter S (or Subchapter R). This is a horse of an entirely different color. 70E recommends testing a device for testing for absence of voltage before and after the actual test, but OSHA only requires testing beforehand. Subchapter R is also a little less restrictive in some cases. OSHA does not specify how to achieve this. 70E points INCORRECTLY to IEC 60101. This is a design standard for test equipment and does not specify acceptable test procedures. Those procedures are elsewhere and include using a volt meter below 1000 volts, and at least 3 different systems above 1000 volts (permanent devices, noncontact capacitive meters, and resistive meters).

There are additional lockout procedures in OSHA 1926 for construction in which case the Grace Engineering device could be used (because that section is in desperate need of updating) but would still fail to be adequate under an existing recognized engineering standard (70E), although you might be able to slip it in under say a risk assessment methodology. I'm sure there are other LOTO regulations but I think I covered the major ones for general industry use.

You don't need the Grace device for Subchapter J. What they would have you believe (but are very careful to avoid) is Subchapter R/S.

I've come up with a scheme to make it work regardless. The idea is to put in a small double throw, 4 pole switch. One side of the switch connects to the Grace device. The other side connects to either the line side of the breaker/disconnect handle, or to the load side. Thus you can use the double throw switch to test BEFORE and AFTER. The downside is that similar to having separate 120 V control power as opposed to individual CPT's in every bucket, when you open the disconnect in the MCC, the double throw switch is never truly "dead" and the same case could be made for the Grace Engineering device unless you can lock out the switch. So it increases the potential exposures in the bucket but does completely eliminate the need for a volt meter unless the switch and/or Grace Engineering device fails.

I never implemented this. I developed it only in response to multiple requests for being able to use their device. It can certainly be used but the end result is much more complicated than the $100/bucket that they advertise. Their noncontact system is even worse. Noncontact voltage measurement for testing for absence of voltage is only recognized in the standards above 1000 volts, and their device is rated only for <1000 volts. So it's useless unless as with either one, you are adding a supplemental step and worried about the rare case when a phase does not clear due to a welded breaker and/or disconnect switch. Since the meter is required anyways and would detect this, the extra cost and extra steps are just redundant, nothing more. Until we can get OSHA to agree to a performance requirement for LOTO, the Grace product is a solution looking for a problem.

We do use it (the one with the LEDs) in Industrial Control Panels because it's easy to know when you blew a main fuse without opening the door of the panel. We don't use them as a help for LOTO. Basically, it replaces an ON light for each phase without being a three-phase voltmeter with a selector switch.
Also, I don't like having full voltage wires (480 V or 600 V) on a hinged door. In a MCC bucket, you're likely to install the device on the door. In a ICP, we install them on top or beneath the disconnect handle (on the small flange in the side).
One thing I don't like about these devices is the size of their wires (#18 AWG). A lot of power switching devices have control taps down to #14 AWG, not #18 AWG. So it's possible your connection isn't as secure as you'd expect it to be.

Not to be flippant or snide...well maybe just a wee bit, but it's just return in kind without makice.

But the fact is Jack, that You do not run Eaton Corporation and they committed themselves to the product WITH its limitations.

It's easy to criticize and find fault with every nuance details but it takes business courage and risk taking to take the best you got know and wait for improvements.

An even better system is the safety system developed by Rockwell. It consists of a number of lockout points to allow easy access, a safety relay, and a pneumatic safety valve as well. There are no single points of failure and it uses all safety-grade designs and equipment. It is in all respects a great demonstration of what can be done with current technology. I don't recall the anticipated failure rate but it is probably 10^-6 or less failures/year and if any one piece of the system fails, it automatically detects this and disables the whole system until repairs are made.

Rockwell submitted the whole thing to OSHA intending on marketing it as a LOTO system. OSHA responded that it is acceptable as a Subchapter O (minor servicing/adjustment and equipment operation) device, but NOT as a general lockout system.

The Grace Engineering device is vastly less complex than the one that Rockwell developed but the basic concept is the same. You can't use their system for Subchapter R/S (electrically safe working condition) lockouts. It is not recognized as a "test for absence of voltage" device because it can't be checked before and after testing. Until we reach the point of having a PERFORMANCE specification to meet OSHA Subchapter J, let alone R/S, we will not be able to throw advanced safety technology at LOTO.