VeriSafe Panel-Mtd. Voltage Tester - Review

Table of contents

RoadTest: VeriSafe Panel-Mtd. Voltage Tester

Author: shabaz

Creation date:

Evaluation Type: Test Equipment

Did you receive all parts the manufacturer stated would be included in the package?: True

What other parts do you consider comparable to this product?: Manual test tools (voltage testers, multimeters)

What were the biggest problems encountered?: No problems encountered

Detailed Review:

Introduction

When doing electrical work there is a real risk of the power accidentally being left on before starting work. Dropping concentration for a few seconds is enough to cause death. Over the weekend I helped a friend repair his hot water boiler, and despite knowing that the power had been switched off, and verifying with a meter, I still felt uncomfortable enough to avoid touching any wiring unless absolutely needed. A fuse of perhaps 5A was fitted, and it would not have helped protect us in the event that the wiring was accidentally still live. It is easy to make a mistake and switch off the incorrect circuit breaker. The dangers are multiplied further in an industrial environment where there is a lot more live wiring, often three phases, and far higher current consumption.

 

What we call a small ‘consumer unit’ or fuseboard in homes in the UK (nowadays there would be circuit breakers and residual current devices (RCD) fitted) is replaced with large cabinets in labs and factories. Wiring the size of pipes is plumbed into the buildings, requiring digging huge trenches. Everything is on a huge scale.

 

According to the US National Fire Protection Association (NFPA) Standard for Electrical Safety in the Workplace (NFPA 70E), establishing a safe work environment involves testing for absence of voltage, and this requires that whatever test equipment you use (voltage tester, multimeter and so on) is verified against a known voltage source both before and after the absence of voltage test is performed. The procedure is quite involved; each phase must be verified, phase-to-phase, and phase-to-ground. Before and after each test, the test equipment must be verified to be functioning against a known voltage source. That’s a lot of test steps!

 

The Panduit ‘VeriSafe’ absence of voltage tester is designed to do all that; it automates the verification procedure, saving the user from having to manually perform these steps, saving time, money and reducing the risk of error. It is basically a device that is permanently wired into the enclosure or controlled area, and it becomes very convenient to do all the tests using a single button-press.

 

Although the NFPA 70E standard is for the US, there could be applicability for the VeriSafe tester in other countries with similar requirements.

 

I was keen to explore this unusual but potentially life-saving product. Here in the UK, I do have some experience with Panduit products, in particular their 19-inch racks. They are known for high quality.

 

This short (5-minute) video provides a quick overview and demo of the VeriSafe solution:

 

 

An Example Lab

One of the labs that I explored contained power distribution units (PDUs) with an emergency cut-off button, and indicator lights for each phase:

 

These PDUs are used to distribute power to aisles of electrical equipment in labs and factories. In this example, a server room is being powered:

 

Sometimes it is achieved with under-floor cabling; here cable trays at ceiling level are used:

 

There are connectors to feed the power all along the aisle:

 

The power requirement to run the server equipment and to cool it all is fairly high! The risks are severe for any engineer who doesn’t ensure a safe work environment when working inside the power cabinets.

 

What's in the Box?

The VeriSafe solution arrived in a very large box, dwarfing my lunch:

 

However, there was a lot in the box – predominantly the cables. The coloured wires are used to connect to all of the phases of power inside the cabinet and to the earth too. Each connection is a pair of wires, i.e. doubled-up for providing a reliable test that can even identify if a cable has become disconnected. The system checks for continuity between the two wires in the pairs basically.

 

It was great to see a very comprehensive 18 page user manual (entirely in English, although the safety warning information page is also in French) inside the box. It is in full colour, with detailed diagrams showing how to perform connections for different wiring systems (three phase delta, wye, single phase and different earthing systems that may be encountered). A set of round stickers is also supplied that are only needed if the VeriSafe product is being installed with different language requirement, and a yellow set of stickers in multiple languages, that has a brief test procedure which can be stuck in a visible location. A nice touch is the QR code on there, for getting all the detailed product information immediately using a mobile phone. Note that it is wise to do this and only use the paper manual as a guideline. The latest VeriSafe online user manual (PDF) should always be used to install this VeriSafe product.

 

The VeriSafe system consists of two key parts; the large isolation module with the multi-colored wires, and a yellow indicator module. The isolation module is wired up to all the phases and to the earth, and then there is a single interconnect cable (with RJ45 style connectors) that joins it to the indicator module that is mounted in a user accessible location. The system is Category 3 (600V) rated.

 

The supplied black 60cm interconnect cable is called the ‘System Cable’ in VeriSafe terminology. Although it looks like it could be replaced with any RJ45 network cable, I believe it is incompatible, and the right-angle part is quite unusual, it fits very deeply inside the indicator module (there is a clip on the indicator module that needs to be partially pulled upward (forcefully) if the cable ever needs removing; it won’t accidentally fall out with vibration).

 

A supplied 3.6V AA sized lithium battery fits inside the indicator module. There are actually a couple of rubber seals (and a small amount of silicone grease), so it is unlikely that dust will get inside this module in ordinary use, and it is approved for wash-down (IP66). The type of plastic wasn’t marked, but it feels very tough.

 

An electrical installer would not need any unusual or additional tool to deploy VeriSafe, apart from perhaps a drill and a punch for a 30mm hole and a 2mm notch. Apparently, this is a standard sized knockout, so no tool may be needed to make the hole. A depth of 90mm is needed behind the knockout for the indicator module. The wires from the isolation module have no supplied connectors, and the wires would be attached to each phase using existing approved connection methods. The user manual goes into the detail of precautions to take and how to route the wires. The isolation module can either snap onto a standard rail (DIN rail) or can be screwed to a surface using three screw holes (screws not supplied; #8, or M4 is the ideal fit for the holes).

 

The indicator module has a simple interface, with just one button to press to start the test. When the wiring is normally live, there will be three lights glowing red to indicate that dangerous voltages are present. When the test is running, a central triangle flashes and then pauses for a few seconds, and then flashes out a code if the environment is not safe to work on. The code tells you (by the number of flashes) if the wiring is live or there is some cable fault.

 

On the other hand, if the environment is safely powered down, then a green outer partial ring glows. That is the only scenario where you can be confident that there is no power, and the environment is safe (engineers should still take precautions however – one can’t predict if someone else will override the power cut-off for example, while you are working. Sensible engineers will place warnings at a minimum, and follow their procedures for ensuring no-one else can switch the power on inadvertently).

 

A nice feature is that the isolation module has four screw terminals that are for two relay contacts that close whenever the system is indicating green. This allows for redundancy by wiring the contacts in series, and the connections can go to a logging system or an industrial IoT system for reporting.

 

Three-Phase Supply Tests

To test the system, I didn’t use a real three phase supply – most individuals do not have access to this, and I wanted to test it in a safe environment before subjecting it to a real mains test.  So, I used a low voltage three phase system. Instead of 208/380/415V RMS (depending on what country you're in), it offers around 6V RMS phase-to-phase! Super-safe, ideal for simulating the power into a factory. Another cool way is to use a variable frequency drive and three step-down transformers.

 

Each of the three phases from the test 3-phase supply were connected to pairs of wires attached to the isolation module. My three-phase test supply has a neutral connection, which I treated as the earth connection. So, all eight wires (two for each phase, and two for earth) from the isolation module were connected to the three-phase test supply.

 

Next I proceeded to run some tests including single points of failure such as a disconnection of one of the wires in a pair from the isolation module. The VeriSafe system behaved as expected. Note that multiple failures are not guaranteed to provide correct indication; for an example, see Peter's RoadTest Review where he identifies and details a scenario where a broken wire falls on a metal chassis connected to earth. There are specific rules on installation that must be followed to prevent a double failure (e.g. using wire ties to prevent a loose wire from falling where it shouldn’t). For situations where more than one fault must not be tolerated, I wouldn’t rule out the idea to install two VeriSafe units, and have a procedure where both units must provide a green signal and both units are to have their relay contacts wired in series to a management platform.

 

Single Phase Mains Supply Tests

With some practice gained in using the VeriSafe product with the safe three-phase supply, I proceeded to hook it up to the single phase real mains supply at home.

 

Here the live and neutral wires are connected to pairs of wires from the isolation module, and the third phase pair and the earth pair are wired together (this is detailed in the VeriSafe user manual). With the mains power switched off, I got the green light as expected.

 

Next, I switched on the mains supply, and the red hazardous voltage indicators came on, again as expected. Pressing the test button caused the triangle to flash a code indicating that voltage was present.

 

Reliability

I was curious, how reliable is the unit, if it is permanently connected in electrical cabinets? The VeriSafe product is designed to achieve a Safety Integrity Level of SIL3, which for this continuous operation product means a probability of failure per hour to be in the range 10-7 to 10-8. In other words, if you had a hundred of these devices deployed, then you could expect to perhaps have to replace one in ten years of continuous operation. Note: I am not a probability or a reliability expert, so please do run the sums if you need to, and let me know in the comments below.

 

In contrast a multimeter is not permanently energised; it is only energised for the length of the tests. However, such a direct comparison is meaningless; an engineer will still use a multimeter and other test tools where needed, and furthermore the risk of not performing the test procedure correctly in ten years is far higher when there are many manual steps to perform, so I’m convinced that the VeriSafe product serves a valuable purpose.

 

Digging further into the safety aspects, the VeriSafe product is designed to meet immunity requirements for safety related systems  based on IEC standards, and meets software requirements for safety related systems too, to IEC standards (the full set is listed in the technical specifications section in the VeriSafe PDF user manual). In terms of electrical requirements, there is no need to have an inline fuse when wiring the isolation module. It is tested to withstand transients of up to 6kV.

 

I was keen to see the internal build quality; there are four screws that hold the IP20 rated isolation module together.

 

The top board performs the majority of the isolation task. The other side of that board contains some physically large disc capacitors, which I believe are Vishay, rated X1 and Y1, designed for permanent connections.

 

The other board contains the processing circuitry. The connections between the boards are with 0.1 inch header pins and sockets, i.e. a board interconnect technique known for reliability (the same techniques are even seen in military equipment).

 

Summary

I love that Panduit thought out-of-the-box to made things safer for engineers in a high risk environment. I was very surprised at the level of sophistication for the VeriSafe Absence of Voltage tester. It is straightforward to install (but read all the instructions, and get familiar with it!) and extremely easy to use, I liked that there is no ambiguity with the indications, a green light is mandatory to determine that the environment is safe to work in (as mentioned, it is wise to still take precautions), and that it collapses multiple manual test steps into a single button-press, eliminating user error in most cases.

 

The internals look well constructed too, and there should be an easy return-on-investment exercise for engineers who know how long it takes them to run manual absence of voltage tests. The risk of making a mistake is of course dramatically reduced, and that should be a huge motivator to evaluate VeriSafe and decide if it is worthwhile to deploy it.

Anonymous
  • The disadvantage is a lack of consistent operation.

    I've seen varying degrees of sensitivity, and we recently checked 4 different ones and found the cheaper versions are usually more sensitive (which = safer).

    Personally I opted for a Fluke version, but in reality most that element14 stock have the necessary requirements for 400v work.

     

     

    neutral back to the source is broken

    Had something very similar in real life. The neutral terminal was not tight and once the load exceeded a certain amount the voltage dropped enough to reset the gear.

    Fixing it was difficult as it was after hours and no access to isolate the supply, so some additional wiring ensued to allow the electrician to loosen and retighten it.

     

    Mark

  • Yes, non contact voltage sticks have their place when testing for voltage presence. The advantage to them is that they are capacitively coupled to voltage presence through the user, so they do not expose the user to direct contact of live terminals and don not require the assumption that the earth / neutral return is intact. The disadvantage is a lack of consistent operation.

     

    Whilst a two probe voltage stick, such as the Duspol, produces more consistent and reliable results, it does have a failing in that if the earth or neutral back to the source is broken, it will not pickup a live terminal. Some will argue that this is an unusual fault, but it doesn't help you much if you are the one it happens to.

     

    Some companies, such as utilities, will opt for testing with both non-contact and a two pole contact probe as the ultimate proof of absence of voltage. There risk of broken neutrals through installation age or copper theft, is a real issue to them and a non-contact probe adds to their safety.

     

    Kind regards

  • the most convenient and versatile I have used is a voltage stick

    It is so easy to check, everyone working on live equipment should be using one.

     

    I was told of an Electrician that had used his Duspol to prove the absense, but he had a voltage stick in his top pocket and it went off as he got close and was about to touch the terminals.

    In this instance he had done the prove-test-prove and nearly got caught by faulty equipment.

     

    I tend to always use the noncontact voltage sticks.

    Better to be safe than harmed.

     

    Mark

  • I would think it will be easy for Panduit to add a 4th test pair in a new product to cover 3 phase and neutral to ground (Just a matter of time I think), in my testing I did find the unit was easily able to detect down to 3V and give a correct indication, I found one fault scenario where the unit gave a false safe indication but this was a contrived fault very un lightly to occur under normal conditions.

     

    This tester is not a "New install tester" and needs to be understood it is testing the absence of voltage in an existing already certified install, does it test better than the manual system... NO, but it is no worse either,  assuming the manual testing procedure was followed to the letter. in this regard and assuming the unit is installed correctly, it is more reliable / repeatable as it is in human nature to take a short cut if under pressure to deliver and people make mistakes from time to time..... Dangerous but it happens all the time. It also provides a much quicker result than a manual process. It could also be used to Augment a safety process rather than completly replace one were the need arises of course. It will never be a substitute for "STUPID" though. but then again, neither is the manual process.

     

    The other part of this device is that the tester is not even remotely exposed to the potential hazard during the testing, with manual testing you are right in there probing arround with metal sticks !!!

     

    The unit will also work for DC supplies so I anticipate uses with Solar and the like in the future,

     

    I had a good conversation with Panduit after my review and as a result they have amended their install guide and added an additional safety note , I was very impressed in their willingness to hear me out and to re-mediate the issue I found. I am now satisfied with the product providing the installer follows the updated install procedure.

     

    here are the two updated documents.

    https://www.panduit.com/content/dam/panduit/en/products/assetfeed/processed/B21052_Rev3.pdf

    https://www.panduit.com/content/dam/panduit/en/general/VeriSafe%20AVT%20Safety%20Notice.pdf

  • Hello Shabaz,

     

    Yes I would say the product is primarily aimed at the US market. However, it looks like their is a CE mark on the product and I am aware of some retailers selling the product with the UK, so presumably Panduit believe the VeriSafe is also applicable to the European market.

     

    Yes the NFPA 70e only requires testing between phases and phase to ground. There are a wide variety supply methodologies within the USA but and they all have a neutral connection. I believe there a 3 phase 4 wire supplies available but are only for use in commercial / industrial environments. From my knowledge of NFPA 70e, absence of voltage tests were only introduced back in 2009 and the acceptance of an automatic voltage test was only included in the last revision. Its use is not mandatory but as an alternative to a hand held tester method.

     

    Neutrals can become live with respect to earth in unbalanced loads and a variety of fault conditions, so are regarded as a live conductor in the UK and are therefore part of the test for dead scenario. There is also a difference in electrical design between the two countries where in the UK a lot of panels will have a main isolator interlocked with the panel door, so power is turned off by default to gain access. I believe that in USA interlocking of that nature is not as common.

     

    If the VeriSafe had an extra channel, then the device could be employed, but for me only in limited circumstances such as main feeders and busbar chambers.

     

    Kind regards

  • Very good road test report.

     

    DAB

  • Funny, but I didn't cut the mains, but unscrewed them from a barrier strip when they were live.  I sure heard it from my classmates for the rest of my time there.  Glad that I lived through that one.

    Gene

  • Hi Gene,

     

    Ouch, that's a scary tale. I've had a small capacitor explode on me, but that's nothing compared to your scenario.

    I've had a couple of other incidents, one was low-voltage but involved someone leaving a large 10xD-cell battery pack on charge (NiCd), using a power supply, and going off to lunch. All the cells popped one by one, and shot across the lab- the first one leaving fragments of ejected content in my eye, but thankfully it was fine. The other time was purely my fault - cutting a mains cable having forgotten it was still plugged in : (

  • Hi Donald,

     

    Thanks for the comments! It is clear you're committed to contributing valuable knowledge, and I appreciate it.

     

    I am not based in the US, so this was quite a challenging product to review, however I'm glad I did, since it provides the opportunity for the experts in the field to read a bit more about the product and provide input that may be missed if no-one reviewed this product.

     

    I did study the specific US NFPA document as best as I could to verify that the VeriSafe system met the rules, and from my interpretation the NFPA document specifies phase-to-phase and phase-to-ground tests, and phase-to-neutral and neutral-to-ground are not covered (I couldn't run a word-search since the document isn't downloadable without a fee, but I did examine it closely). With all the power grid scenarios that are in the VeriSafe user guide (pages 8-10), connections are only made to the phases and to ground. I agree that testing neutral is also good, it appears the UK isolation procedures are diverged from the US ones on that point if my reading of the document is correct (which it may not be). I'd be speculating to say why; it could be their most commonly used wiring systems are different. Furthermore, their standard does explicitly state that the tests can be permanently wired - I appreciate there is uncomfortableness with this compared to physically inserting a test tool to perform the same tests manually, visually examining each result at each stage of the procedure.

     

    So, on paper according to the reading of the rules, and from the tests performed, the device performs correctly, and based on the amount of time it would take testing the pairs specified and the opportunity for error, the product would appear to reduce the risk of error since it reduces it all to a single button-press and a green indication. I also did test all single fault combinations that I could think of, but can test anything specific if requested. I agree that where there are multiple circuits to separately verify, the cost of multiple devices could be expensive, but it should be easy to rule in or out through a simple calculation for anyone interested, if they know the cost of their time and how long they would take.

     

    You're right that the photos are from the UK, I would have taken the opportunity to use a US workplace, and I may request some photos from overseas engineers to update this review at some point if I do not get to visit anytime soon. The point of the photos was to set the scenario where the product is useful, but I was not suggesting that it met UK rules or codes of practice specifically, just that it could have applicability in countries beyond the US.

     

    By the way my qualifications are in engineering but not in the field of electrical installs : ( I try to always be careful not to write anything incorrect or misleading, but do need help from time to time from people, and I found your comments valuable. I can see an opportunity for Panduit to go beyond that US NFPA standard and introduce an additional pair of cables for neutral testing too. But it is also clear that they may need to find ways to go even further, to provide comfortableness to engineers who would rather manually check at each step of that procedure. The standard doesn't say that if a permanent test system is installed that it has to be used; it states such a system 'shall be permitted to be used' to verify the absence of voltage, i.e. I think it is allowing the engineer's (or his/her firms) procedures to be used to make that choice to use the automated system or not. It might be that it is an unsolvable problem for manufacturers to provide the assurance to engineers who prefer to manually execute the procedures, but it would be interesting to explore what things could be done with an ideal system to go further to provide more assurance beyond what the standard says.

  • a very good detailed review and inspection of the VeriSafe. I have been looking at the device for a while now following the initial road test by and to be honest, I am not convinced that the device provides an improved level of safety against the procedures that I already use.

     

    In your example of the PDUs in a lab, the VeriSafe would not actually function correctly as it is not compatible with a 3 phase, 4 wire system that will be in use in that kind of a facility. The VeriSafe only has 4 channels, so cannot test the neutral conductor, which is classified as a live conductor and must also be tested. So your description of testing for dead needs to be extended to include the neutral. i.e. each phase is tested against one another, each phase to neutral, each phase to earth and then neutral to earth.

     

    When initially reviewing the VeriSafe, I did think it would be good for main LV feeds and busbar chambers, but due to the above, I no longer believe that.

     

    The system isn't also designed for use on systems fed from variable speed drives as identified in their own literature.

     

    If VeriSafe devices are introduced, but cannot be used on all circuits, then a different test for dead procedure must be used for those incompatible circuits. This introduces multiple methodologies for a critical safety procedure, and in my humble opinion, has the potential to produce confusion and more likely to lead to incidents occurring.

     

    I am aware of incidents with people using multi-meters for testing for dead procedures, but I am not aware of any incidents carried out by trained electricians using voltage sticks to GS38 and a proving unit, certainly within the UK.

     

    A large driver for this VeriSafe seems to be speeding up the testing for dead procedure. To be honest, such an approach makes me shudder. Speeding up safety procedures very rarely provides improvements. Testing for dead is not a chore, to be got out of the way as quickly as possible. It is an opportunity for the electrician to take a step back and look at what they are working on, where the sources of supply come in, potential back feeds and stored energy and look at the schematics. If it takes an electrician 10 minutes to do that, but gives them the confidence that what they are working on is safe, then for me, that is the best 10 minutes they will have spent that day.

     

    In terms of time spent, looking at the video you produced, the VeriSafe took around 5 seconds to operate. The equivalent test for dead tests I did in a motor starter took 15 seconds. That is a saving of 10 seconds, based on the average sparky wage in my industry, it would take circa 12 years to pay back on the device if one test for dead was carried out each day.

     

    There is however, the issue of how many VeriSafe units are required. For a motor starter, I test for dead on the incoming supply, outgoing feed to motor and control circuits. There is then the motor itself, one VeriSafe for the motor and another for the motor heater. That is potentially five VeriSafe units to cover an individual starter and motor.

     

    The VeriSafe retails for the cost of a top brand name voltage tester and proving unit, with a lock out kit thrown in. I can use that system for all the aspects of the starter and motor, that I would need up to five VeriSafe units to carry out an equivalent test. I am struggling to see how that adds up to cost savings.

     

    I am also struggling to come to terms with the operation of the VeriSafe. In my mind, I still have to make an assumption that the VeriSafe is installed correctly, that its wiring hasn't been altered over the years that produces a fail to danger scenario. With a voltage stick and proving unit, I do not need to make any such assumptions, I can see what I am testing and verifying is dead.

     

    You state that electrical work is a very dangerous business. I respectably disagree with you. When worked on correctly, following the right safety procedures and work practices, electricity is no more dangerous than any other trade. You will probably find in the UK that more people are hurt crossing the road than working on electrics. Unfortunately, the harsh reality of why incidents occur, are the people that work on it and the manner in which they go about things.

     

    I am not trying to undermine your review any way or be disrespectable to you, and I apologise now if this post has come across this way. Some may argue I am stuck in my ways and cannot adapt to new technology, which may be true, but those ways I was taught, have protected me and many others throughout the years, and I have seen what happens when some don't follow those working practices.

     

    Kind regards