Fingersafe

[petersonra]

Does working in a panel where all connections are "fingersafe" prevent expose of a worker to dangerous voltages?

 

[K8MHZ]

Does working in a panel where all connections are "fingersafe" prevent expose of a worker to dangerous voltages?

Isn't that the idea???

At least, so long as the switch is in the off position, that is.

In class we learned that the design was meant for systems with multiple power sources. In a regular panel, with the switch in the off position, the load terminals are exposed. If the panel is being backfed, that means there will be exposed energized parts even with the switch off. In a finger safe design, supposedly, there wouldn't be.

 

[renosteinke]

"Fingersafe" means that the screws, etc., are shrouded or positioned that your fingers can't touch them. There might still be access to the with a screwdriver or other tool.

 

[don_resqcapt19]

While it may be finger safe, it is still working on or near energized electrical equipment and will trigger the shock and arc flash PPE requirements.

 

[Steve Merrick]

Finger safe

Finger safe

If the inside of the panel meets IP20 "finger-safe" requirements in accordance with IEC 60529, then there are no "exposed" live parts as defined by NFPA 70E and PPE requirements may be reduced accordingly. As long as all components are "suitably guarded, isolated or insulated," then under NFPA 70E Article 100 they are not considered to be "Exposed (as applied to energized electrical conductors or circuit parts)." Since with 100 percent fingersafe panels there and no live parts to which a worker might be exposed, the approach limitations and PPE requirements under Article 130 do not apply. If you are opening the panel for inspection purposes only and you are not using tools or otherwise making contact with potentially live parts, then no additional PPE is required - again, so long as no tools are involved in the work activity.

Remember, Article 130 is all about working on or around exposed live parts. If the parts are all suitably guarded, isolated or insulated they are not "exposed."

Consider a standard 120 volt receptacle. A receptacle with its cover plate installed is considered IP22 compliant (finger safe, drip proof). It has live parts, but they are suitably guarded, isolated and/or insulated, and therefore we are not required to wear PPE to plug in an appliance, and we are we are allowed to approach closer than 4-feet without wearing arc-flash protection.

With that said, sometimes hidden hazards do exist (uncovered power terminals, etc.). it is up to the electrical workers to be qualified to know and recognize the potential work hazards involved and to wear the appropriate level of PPE accordingly, and if work acitvities evolve from inspection only to troubleshooting and beyond to where they may indeed become exposed to potentially live parts, then they must be willing to immediately stop work and regroup and take appropriate precautions for the expanded work (lockout/tagout, live work permits, PPE, approach limits, barricades, etc.)

 

[weressl]

If the inside of the panel meets IP20 "finger-safe" requirements in accordance with IEC 60529, then there are no "exposed" live parts as defined by NFPA 70E and PPE requirements may be reduced accordingly.

Incorrect assumption. NFPA makes NO such conclusions. NFPA makes not distinction if you are to enter a panel with or without tools, NFPA - contrary to IEC - does not spell out that you need to use insulated tools or otehr and how does it affect your exposure to danger.

 

[Steve Merrick]

NFPA 70E is clear that it applies to work on or around exposed live parts. NFPA 70E Article 100 provides a clear definition of what it means by the term "exposed" as follows:

"Exposed (as applied to energized electrical conductors or circuit parts). Capable of being inadvertently touched or approached nearer than a safe distance by a person. It is
applied to electrical conductors or circuit parts that are not suitably guarded, isolated, or insulated."

Wires in a conduit are guarded by the rigid steel and insulated by their jackets, hence you can put your bare hand on a conduit carrying energized conductors without wearing PPE. Live contacts in a receptacle are isolated by the narrow finger-safe slots that can be contacted by a tool, but not inadvertently by a person and are again not covered by 70E requirements.

As there is no US definition of finger safe, manufacturers and AHJs have been using IEC-60529, the international Ingress Protection standard, or IP Code, as a basis for determining if a part is suitably guarded, isolated, or insulated for the porposes of NFPA 70E. This standard holds that an assembly is considered finger-safe (IP-2X compliant) if a 12.5 mm (1/2 inch) metal sphere probe 80 mm in length (the size of an average little finger) is unable to make contact with any potentially energized circuit component within the assembly.

Again, if a worker is not "exposed" to hazardous energy as defined, NPFA 70E protection requirements do not apply. This is not simply my opinion - I have been an insider on this from the beginning. If you think otherwise, consider how you could justify allowing unqualified, unprotected people to change a light bulb or plug in a tool or appliance. They are certainly approaching live parts carrying greater than 50 volts. How is it different because it is in a panel?

 

[jim dungar]

Again, if a worker is not "exposed" to hazardous energy as defined, NPFA 70E protection requirements do not apply.

Correct NFPA70E shock protection requirements do not apply, however the informational note to 130.4(B), in the 2012 version, makes it clear that arc flash PPE may still be required.

 

[don_resqcapt19]

Steve,
What if you are using tools? It is my understanding that finger safe does not prevent you from touching energized parts with tools, so in my opinion, if you are using tools in a panel with finger safe terminals you are exposed to energized parts.

 

[PetrosA]

Steve,
What if you are using tools? It is my understanding that finger safe does not prevent you from touching energized parts with tools, so in my opinion, if you are using tools in a panel with finger safe terminals you are exposed to energized parts.

In my experience, in countries where the concept of "finger-safe" does exist you would never use a bare, uninsulated tool like we do here in the US. I could insert any of my Wiha screwdrivers into a finger-safe screw terminal and it would maintain its finger-safe status with no energized parts exposed. The new generation of CAT rated test leads with shrouded tips are also designed to extend the finger-safe rating to an inserted, energized probe.

 

[pfalcon]

Steve,
What if you are using tools? It is my understanding that finger safe does not prevent you from touching energized parts with tools, so in my opinion, if you are using tools in a panel with finger safe terminals you are exposed to energized parts.

Works the same as with all guarding, from the ANSI-B11 series to the various NFPA series of standards. The definitions are written under the presumption of "without undue force or the use of tools".

So YES. The moment you pick up a tool or meter to service the panel then you are potentially "exposing" hazardous voltages. Hazard protections may immediately become elevated as though the panel was not finger-safe.

... If the equipment has ventilation openings, wires and tools could be inserted through the ventilation holes and contact energized conductors; therefore, the level of exposure is based on the task and associated tools and equipment. ...

Strangely there is no general definition for "exposed". Each of the definitions in that article are qualified with "(as applied to ..." so general exposure is not actually defined but inferred.

 

[don_resqcapt19]

In my experience, in countries where the concept of "finger-safe" does exist you would never use a bare, uninsulated tool like we do here in the US. I could insert any of my Wiha screwdrivers into a finger-safe screw terminal and it would maintain its finger-safe status with no energized parts exposed. The new generation of CAT rated test leads with shrouded tips are also designed to extend the finger-safe rating to an inserted, energized probe.

It is my understanding that using insulated tools does not remove the requirement to use voltage rated gloves.