Innovative solutions to dealing with NFPA 70E

We adopted NFPA 70E a few years back, and as usual, our safety people haven't taken the time to understand the standard (which I find easy to read and well written) and have gone overboard, and taken a good program and turned it into a painful disaster (permit and full arc flash gear required to open a panel to verify the feed is dead after isolating and applying lock-out tag-out). Makes it a little tough when all you want to do is pop open a panel long enough to see what the fault code on a VFD is.

So it's forced us to start looking at alternatives to the opening the panels. We've found some cool stuff, and I was curious to know how other professionals have been adapting.

Graceport has some useful products:
Voltage indicator - http://www.graceport.com/prod_voltage.cfm

Non-contact test point for outside the enclosure http://www.graceport.com/prod_checkvolt.cfm

Configurable Panel through-ports for programming:
http://www.graceport.com/prod_gp.cfm

Hoffman and Wiegmann Have window kits and panels with polycarbonate windows that are Nema rated. Great for placing over PLC I/O and VFD displays.

On any new equipment I think I'm going to require that the enclosure have polycarbonate windows. I found a company that seems to specialize in Nema rated enclosures with this kind of panel door, but the link is on my work computer.

Any other cool products you guys are using?

Wait, so your panels aren't rated? There was no arc flash study done? Is that why you need the full arc flash gear?

I had the plant manager attempt to call me out when I was looking inside of a panel a few weeks ago, saying "WHERE'S YOUR SUIT AT?" and I was able to casually explain to him that well, for starters it was a category 0 panel, so I wouldn't need a flash suit and secondly I was not within the flash hazard boundary, so I needed no PPE(It was 3 inches on this panel).

If it's not prohibitively expensive I'd suggest a study.

By the way, we use several Graceport products and I would certainly recommend them.

You mentioned checking VFDs - what VFDs are you using? We primarily use Mitsubishis and more often than not opt for the VFD operator panel to be mounted to the enclosure door.

Matrix approach. We're a huge company and we'd end up contracting someone to do the studies for us, so it would be a huge expense. Not to mention that it has to be re-done after any change or five years regardless.

monkeyhead said:

We adopted NFPA 70E a few years back, and as usual, our safety people haven't taken the time to understand the standard (which I find easy to read and well written) and have gone overboard, and taken a good program and turned it into a painful disaster (permit and full arc flash gear required to open a panel to verify the feed is dead after isolating and applying lock-out tag-out). Makes it a little tough when all you want to do is pop open a panel long enough to see what the fault code on a VFD is.

So it's forced us to start looking at alternatives to the opening the panels. We've found some cool stuff, and I was curious to know how other professionals have been adapting.

Graceport has some useful products:
Voltage indicator - http://www.graceport.com/prod_voltage.cfm

Non-contact test point for outside the enclosure http://www.graceport.com/prod_checkvolt.cfm

Configurable Panel through-ports for programming:
http://www.graceport.com/prod_gp.cfm

Hoffman and Wiegmann Have window kits and panels with polycarbonate windows that are Nema rated. Great for placing over PLC I/O and VFD displays.

On any new equipment I think I'm going to require that the enclosure have polycarbonate windows. I found a company that seems to specialize in Nema rated enclosures with this kind of panel door, but the link is on my work computer.

Any other cool products you guys are using?

Click to expand...

Regarding the "checkvolt" product, are they suggesting we use these cheap-a## non-contact testers to verify voltage? I have had several and never really trusted any of them, that's why you use a more expensive CAT-III meter. I know..... then take the time to suit up w/arc flash, etc. etc. Just seems wrong to me.

How do others feel about these non-contact sensors?

We use a lot of Graceports. For the last couple years we have been designing every machine we build in-house to have separate panels, one with just 24VDC, one with 120/480...most things nowadays, the only reason we even have 120 is for a receptacle for a laptop. We also like to put in a window in the 480V panels to see the drives.

I always wondered and cried about having to open a panel just to read something inside. So I think windows are a good thing - properly designed all safetied up and all that stuff.

Non contact sensors. I carry one always. It is great for troubleshooting. I do not rely trust 100% and will use a VOM to ensure dead before I stick my fingers in there.

Dan Bentler

We also go to great lengths to keep from suiting up.

We mount drive hims remotly and sometimes we use these http://www.hoffmanonline.com/produc...159987&cat_3=163442&catID=163442&itemID=42307 in the panel door to mount the him remotly while still protecting it from damage

We use the led cabinet lights with a on/off switch on the enclosure door which helps if you have windows in the panels http://www.hoffmanonline.com/produc...2=77342&cat_3=77347&catID=77347&itemID=256733

We also have contactors on the line side of all drives that can be controlled only from the maintenance screen on the hmi which is used to reset hard faults on a single drive which we have a need for.

We are an ab plant so we use faceplates for switch,plc and drives status on our hmi units.

We use a lot of the graceport stuff also. Most of our new layouts include a ethernet connection,serial to the plc,power receptacle and cli port for the ethernet switchs.

We use breakers with aux contacts to signal on or off condition as well as measure supply voltage or current on many components.

We use sequster panels for our disconnects to isolate 480 http://www.mc-mc.com/portals/1/Product Content/articles/0807_hoffman.htm

http://www.hoffmanonline.com/produc...29999&catid=129999&itemid=89887&view=overview

We also seperate plc and logic controls from 480 starters and drives as well as use aux contacts on startes and e3 overloads to monitor status and conditions.

This is what I've received in NEC newsletter:

Question:
Is a proximity voltage detector appropriate for establishing an electrically safe work condition?

[FONT=Arial, Helvetica, sans-serif]Answer:
[/FONT]NFPA 70E does not prohibit the use of any test instruments, but requires in 130.4 that the user be a qualified person and in 110.6(D)(1)(e) that the user be proficient in the use and understand the limitations of all voltage detectors. Verification of an electrically safe work condition is accomplished by a specific procedure in 120.1. Step (5) of the procedure mandates that each phase be tested "both phase-to-phase and phase-to-ground." This action exceeds the limitation of a proximity tester.

Electricians working on electrical conductors, should never get out of the habit 'test-before-touch' and validating their meters.

With that said, here is a response that was sent into a publication on the same topic.
Keeping personnel away from live voltage is foundational to electrical safety. More importantly, electrical safety demands a precise answer to the question ‘Is voltage present?’. Permanently mounted voltage detectors (voltage indicator and ChekVolt) go a long way in providing the very first answer this question, while a voltmeter provides personnel with a second redundant answer. Lastly, voltage indicators provide visibility of voltage from outside the enclosure without exposing personnel to voltage.

Training and Written LOTO Procedures:
A thru-door voltage detector used in a safety program, must be written in to the LOTO procedure [NFPA 70E 120.(C)(2)]. Employees must be trained in using voltage detectors [NFPA 70E 110.6(D)(4)(e)].

Increase Productivity and Safety with Mechanical LOTO:
Workers performing mechanical LOTO procedures must isolate electrical energy. An externally-mounted voltage detector provides a means to check voltage inside an electrical panel. Without these type of device(s), a mechanic performing mechanical LOTO would be required to work in tandem with an electrician using a voltmeter to physically verify voltage inside an electrical panel. In this case, the electrician is exposed to voltage. With thru-door voltage detectors, the mechanic can verify zero electrical energy without any exposure to voltage.


Reduced Voltage Exposure and Arc Flash Risk
Voltage is the common denominator in an electrical accident or an arc flash; No voltage means: No accident, No arc flash. While performing electrical LOTO with a voltage detector installed, the electrician can pre-check the internal voltage state without opening the enclosure. Next, the electrician should replicate a zero voltage reading with his voltmeter as per NFPA 70e 120.1.(5) This low-cost, redundant voltage-verification task reduces arc flash risk and increases electrical safety for electricians for around the $150 installed cost.

Other benefits of through panel voltage detectors:
· Permanent Device: Unlike a voltmeter, a voltage detector is a permanent part of an electrical system. A voltage indicator has the ability to continuously check voltage between each phase and ground, thereby creating a safer environment for maintenance workers. A voltage indicator is maintenance-free because it receives its power from the line voltage, not from batteries. Permanent voltage detectors are less prone to damage because they cannot fall out of a tool belt like a voltmeter.
· Fuse Status & Power Indicator: Under NFPA 70E, checking fuses or verifying system power requires workers to wear proper personnel protective equipment in addition to performing their LOTO procedure. Having fuse and power status information readily available with a voltage indicator on the outside of the electrical enclosure has proven to eliminate reasons for workers to access the enclosure.
· Labeling Voltage Sources: By wiring voltage detectors to every voltage source inside an enclosure, an electrician immediately knows the location and number of voltage sources feeding the enclosure.
· Stored Energy Detector: The NFPA 70E recognizes the danger of induced voltages or stored electrical energy [NFPA 70e 120.1(6)]. Since stored energy shows up as AC or DC voltages, a voltage indicator alerts personnel to it presence.
· ‘Visible Blade’ Disconnect: For disconnects or circuit breakers without visible blades, a voltage detector is an indication that the blades are fully open. “Wherever possible, visually verify that all the blades…are fully open” [NFPA 70e 120.1(3)].
· Reduced Arc Flash Risk: Using voltmeters to check for voltage on incoming disconnects creates an opportunity for an arc flash. High incident energy (Category 3 & 4) panels further intensify this danger. Safety is a natural byproduct when a voltage detector pre-checks voltage before an electrician performs his voltmeter check.

Response to Promity Detectors

paulB said:

This is what I've received in NEC newsletter:

Question:
Is a proximity voltage detector appropriate for establishing an electrically safe work condition?

[FONT=Arial, Helvetica, sans-serif]Answer:
[/FONT]NFPA 70E does not prohibit the use of any test instruments, but requires in 130.4 that the user be a qualified person and in 110.6(D)(1)(e) that the user be proficient in the use and understand the limitations of all voltage detectors. Verification of an electrically safe work condition is accomplished by a specific procedure in 120.1. Step (5) of the procedure mandates that each phase be tested "both phase-to-phase and phase-to-ground." This action exceeds the limitation of a proximity tester.

Click to expand...

I agree with this statement. However, a combination of a voltage indicator and chekvolt on the outside of the panel gets us a lot closer to meeting 120.1(5). A voltage indicator does the "both phase-to-phase and phase-to-ground.", while the chekvolt-proximity detector allows for the proximty tester to be retested after the disconnect is open. A voltage indicator uses LED's so there is no practical way to retest such a device after the disconnect is open.

The big time saver in thru-door voltage detection is for mechanical maintenance. Reduceing PPE to access a control panel is another benefit.

Electricians working on electrical conductors, should never get out of the habit 'test-before-touch' and validating their meters.

So after reading Phil's responses, my interpretation is that even IF the panel has BOTH the Voltage Detect hockey-puck lights and the Non-contact sensor doo-dad a person still has to use a volt meter to check phase-to-phase and EACH phase-to-ground. That would be six (6) tests...A-B, A-C, B-C, A-GND, B-GND, C-GND.

The hockey-puck only has 4 lights, not 6.

So I don't see that these devices eliminate the need for setting up for live voltage testing (if 480V then it's probably gloves, mats, face shield, coveralls, etc.)

Why spend the extra $$$$ on these devices then? Please correct me if I'm wrong.

The Grace devices have 8 lights, which is what makes it a redundant device. I'm not sure what the thing would do if you energized all three legs at, for example, 100 VDC. I know in cases where there is phase imbalance the GND indicator flashes.

All 120.1(5) says is you need to use an "adequately rated voltage detector". From what I have read it makes no determination of either what constitures adequately rated or specifies any given device as a voltage detector. I would submit that the Grace device satisfies both parts of this requirement. If the device is flashing prior to LOTO you can be confident that it is detecting voltage. If it stops flashing after LOTO you know it is not detecting voltage. Those two case cover the check and measurement requirements of all three phase to phase cases. The place where it comes up short is the testing of phase to ground voltage and confirming that the measuring device is actually functioning. It may handle this correcly also but I can't guarantee that.

Having said that, even if I consider 120.1(5) statisfied by a Grace-style voltage indicator I would still check the thing with a voltmeter, just as a final check. But I wouldn't suit up to do it at that point. I would be 99.99% sure the supply is dead, but I would still try and pick up the last 0.01%. And in reality I STILL wouldn't be 100% sure. But at that point it is no different than jumping on an airplane.

As a side note, how do you guys satisfy the check clause in 120.1(5)? Do you carry an independent voltage source or do you test the line side of the disconnect?

Keith

Keith we where doing line side checks until our safety person said that is still on you have to have PPE. Now we do enclosure source isolation. Local isolation is no longer allowed. We walk a lot.
Every time my ears are blessed to hear someone else complaining about walking. I let them know that don’t have to hit the treadmill when they get home or they should think of all the years we are adding to their lives by helping them exercise.

We require line side isolation. Most of our panels have through the door disconnects anyway, so there is no way to lock them with the panel door open other than going upstream to the source circuit breaker.

We've begun outfitting our panels with separate disconnects on the outside of the enclosure. Like Jeff, we do a lot of walking for the control panels that feed straight back to a circuit breaker in a distribution panel.

One of the Grace options is to have both products combined. Between seeing the LEDs turn off and the proximity test points, I'd feel confident that the hazardous voltage was gone. If you read the label, I think they also recommend re-verifying with a volt-meter, which I would do anyway. I've been shocked enough times in my life to make me a little paranoid. I make it a habit to test anything I touch with my volt meter. I like the redundancy of the whole thing, (and the fact that I don't need to suit up in HRC-2* gear for a 30 second test!)