I had a question asked of me that I could not find and answer for in the NFPA 70E.
What does the NFPA 70E consider troubleshooting?
An exception to getting an EEWP is troubleshooting but if troubleshooting requires tools it is recommended that insulated tools be used.
So is there anyplace that the NFPA 70E defines what is troubleshooting and where does the line stand for having to get an EEWP?
For example, If I find a blown fuse during troubleshooting a 120 VAC circuit do I have to then put the equipment in an ESWC to put in a new fuse?
Thanks
psears

Hello

In the 2018 edition of NFPA 70E, in Article 100, Definitions, on the bottom of page 13 where it defines "Working On" you will see the 2 categories of working on. "Diagnostic" (testing) which is considered working on energized conductors and circuit parts is defined there. You will also see "repair" defined also. Further up in the standard in Article 130, page 23 under "Exemptions to the Work Permit" you will see that testing, troubleshootiong is exempt form the EEWP

With regards to the fuse replacement on a 120 Volt circuit, you may have to be a little more descriptive to us. Is this an inline fues perhaps? Is there a type of disconnecting means that would isolate the fuse from incoming power? Neverthless if you are installing/ removing a fuse I would at least isolate and test for the absence of voltage prior to installing

I hope that this helps
All the Best

The short answer is trouble shooting is the same as testing. Maintenance means you are adjusting or removing and replacing. Your trouble shooting involves touching with meter leads or inspecting. At no time are you doing anything other that attempting to find a fault. Once you find the fault, then it becomes maintenance and you must shut off power.
An example is locating a blown fuse which is testing. You cannot remove or install a new fuse with the power on.
Suppose you find a bad connection. The process of finding that bad connection is testing because you are not adjusting or repairing that connection. Once you have determined that bad connection is the problem, to fix it you must shut power off.
The only time an energized work permit can be used is if it is determined shutting power off is more hazardous than leaving it on.

Thanks for the clarifications.
The question came up during a discussion about on-site troubleshooting and commissioning of switchgear and when and if an EEWP was required to do the work.
In the process of locating the fault or verifying the circuit, the technicians will remove fuses, disconnect plugs and lift energized terminations.
The justification is that the control voltage is 120 VAC and does not reflect an Arc Flash Condition and therefore a EEWP is not required.
The general attitude is that the EEWP exceptions allowing testing, troubleshooting and voltage measuring also allows the technician to perform these tasks while the power is on.
The question of what is the NFPA definition of troubleshooting then comes up as does at what point during these procedures does an EEWP need to be utilized.

psears

I see this often. People only focused on arc flash and seem to ignore the shock hazard.

EEWP is about recognizing and addressing all hazards.
I believe more people are injured by electrical shock and falls, than by an arc flash.

I need to clarify my previous answer to your question. I find the simplest way to decided if it's trouble shooting is to consider if you are adjusting , like tightening or moving some connection or contact or removing and replacing a fuse, or a breaker, or an overload heater, or repairing a termination or replacing some part, like a control transformer. The testing piece involves some kind of meter and meter leads.

The only time you'd use an energized work permit is if something is more dangerous to shut off than it is to leave on. Examples could be a vent in a hospital ward where there is COVID-19. The justification is the room must maintain a negative pressure and shutting this off could allow the virus to move throughout the hospital. Another is a venting system where there are dangerous chemicals; chemicals that could hurt someone. Another is a control system to a reactor. What about a UPS to a computer system? Sorry, that does not meet the definition unless the UPS was controlling something like that vent for the COVID virus ward. Just because shutting something off is inconvenient does not make it worthy of an energized work permit. I used to teach this stuff and got this question from an older electrician. "Do I have to shut off power just to replace this single pole switch?" He pointed to the light switch in the room. The lighting in this office was 277 volts. The student reasoned that the space was often full of people, and it would be inconvenient to shut off power. I asked him as well as the class, "isn't your death inconvenient? Why not come back when the office is empty? How about doing it after hours?" He replied 'but that would mean overtime!" "Okay, they pay a little OT to save your life. Is that such a bid deal?

It's a very very high bar to justify an energized work permit.

For some clarity, in that same cabinet there could be 480V parts, therefore, insulated tools are required when within 12" of live/exposed conductors/parts at 480 volts. I could also argue that when the 120V comes from a 120/240 or 120/208 *source, you need insulated tools when closer than 12" to live/exposed conductors/parts.

*see 70E, page 24

This is how I think about it, if you need a screwdriver its NOT testing or troublshooting; its work.

Troubleshooting should never require tools, the tools are there to do the work to fix or try something you found when troubleshooting.

Once you need to life a tool, you are no longer troubleshooting/testing, you are working and you should have a EEWP.

The example that you give to a blown fuse is interesting, in most cases I would say that this should be covered in a Standard Operating Procedure (SOP) and therefore not need a EEWP, however, that SOP would include the requirement to follow the necessary procedures to lower the risk to the worker to an acceptable level. That may be wearing proper PPE, de-energization, etc.

I agree with the statement that it goes beyond troubleshooting when you have to start using tools,( removing components, rewiring circuits, etc)
The bone of contention that I keep running into is whether the boundaries apply when the barriers/shields have not been removed.
I have been told that in a 480v switchgear cabinet if the outer doors are closed than the shock and arc flash barriers are not applicable because no exposed conductors exist. If the front door is opened than there is exposed 120/240v conductors ( terminal strips, contactors, etc.) so the shock hazard boundaries are in state but since the barriers to the 480v conductors have not been exposed the arc flash boundary is not in place.
My opinion is that you must be aware of what hazards you are being exposed to or may be exposed to before you begin your work and approach all work from the worst case scenarios.
For example our commissioning technicians use jumpers to activate circuitry to components while performing circuit test and point out that de-activating power to install and remove the jumper is unnecessary. I have done this myself several times but question the logic that shock protection is not needed while performing this task. I point out that if a jumper is misplaced or a component is defective this can result in serious injury.
It is a difficult process to instill the idea of safety in the performance of troubleshooting/ commissioning tasks when the major contention is the inconvenience and additional time that will be involved.
Most of these tasks have been performance evaluated and the timeline for average completion is based on unsafe work practices that ignore safe procedures.

This is the exact philosophy that NFPA 70E and CSA Z462 are trying to enforce. Awareness of the hazards and the risks associated with those hazards.

I think you know the right answer and from your reply you seem to have a great grasp on what the "right" answer is, but its not a digital decision, its a risk analysis. I typically think in low-med-high risk, and only want a worker to be exposed to a low risk scenario when doing their work. For me, this means that there is a low risk of an injury occurring and that injury will be minimal or not life altering.



If the control voltage is over 30V, then I agree, shock protection is 100% required. There is, in my opinion, a chance of contact and therefore death. Its the reverse lottery, you lose once. I know plenty of people, including myself, that have been "biten" by 120Vac or 125Vdc, we joked about it at the time, and never would of considered it a "near-miss". Today, I look back at my younger self and think he was an idiot.

Sure the likelihood of me dying was low, but you only die once.


Yep. Try to explain to them that if there is an incident, think of the time that will be lost, both to the project and to the person affected. I have read accounts where someone was mildly shocked and then tripped and fell, hitting their head and getting a concussion. They were never able to work at the same capacity again. Sure, there are probably old timers that have been "bitten" many times, and are the tough guys. But if they fell and hit their head because they couldn't be bothered putting on gloves, and then never able to play with their grandkids, would they want to make that choice?.

I feel like I'm preaching to the choir.

What has worked for me in the past is to talk to the individual and help them understand the likely outcomes IF there is an incident. It may help them understand that you are only looking out for their life and retirement.