So a part of our lockout procedure for motors is to pull the fuses from the MCC disconnect. After opening the disconnect, the electrician dons appropriate PPE and removes fuses. There are no exposed energized parts while the door is open, but a fault on that bucket while the door is open would increase the likelihood of injury and exposure to the electrician.

Am I interpreting this correctly that pulling fuses from an MCC disconnect would require an energized work permit?

I would say yes you are interpreting it correctly. While there is no voltage on the fuse, there is voltage in the bucket. If something goes wrong and makes contact with the incoming bus/wires there could be an arc flash. Depending where that bucket is, it is my opinion, there could be a secondary incident at the mains also (up to debate and discussion). We always rate the MCC's with the worst case.

I agree, with the second post, your people should wear PPE. Question: I'll bet I misunderstood you, but do they put on PPE before or after they open the door to the bucket? Not to nitpick, but . . . Thanks and good luck

A PERMIT has nothing to do with PPE. They are related subjects but one does not trigger the other. Permits are required for energized work except for:
1. <50 V.
2. Visual or similar inspections (thermal or UV cameras).
3. Diagnostic readings such as voltage testing where energized work is inherent in the task.
4. Startups...same as #3 but it looks like 70E may do away with this in the 2018 draft.
5. Tasks involved in de-energizing equipment for safe work (LOTO).

The whole point of the energized work permit in the first place is an administrative rule designed to make especially front line personnel think twice about doing energized work and get them to try to find ways to do the work without being energized. It would be patently stupid to use an energized work permit when the task is to de-energize in the first place or the "teeth" for this process totally disappears. Similarly it's pointless to do an energized work permit for instance on voltage checking for the opposite reason (can't de-energize and then do a voltage check).

So you would require arc flash and possibly shock PPE to do a lot of the diagnostic work. A good case in point is using an amp clamp. Prying around and moving cables with insulation that may have been overheated and may flake off while getting a reading or that may otherwise be damaged for whatever reason is a great reason that shock and/or arc flash PPE must be worn. An energized work permit is not required because doing diagnostic work of this nature is inherently energized. But obviously that doesn't mean the PPE requirement goes away.

So I disagree with the others. You don't do an energized work permit just because you get out the arc flash or shock PPE. The reason that you use an energized work permit is because you are doing energized work that could be done without being energized.

But in your case, you're not doing energized work or at best, you are in the process of de-energizing, which at least with the voltage test as a minimum, is inherently energized work. But not work that requires a permit. This is clear in the "EXCEPTION" in the 2012 and 2015 editions that is AT BEST, completely unparseable. I put in a public input to change this but was shot down.

I can't put this in writing (e.g. point to an OSHA letter of interpretation) but I asked this exact question and got the same answer from OSHA...doing energized work permits to do LOTO is silly and totally destroys the whole purpose in doing them in the first place. If I had to do an energized work permit whether or not I did LOTO, I probably wouldn't bother doing LOTO anymore and just come up with creative ways to bypass the limitations on doing energized work.

Thanks, Paul. I agree with what you are saying- an EWP for LOTO is, at best, stupid. However, is there actually a written exception to this in the standard? I can't seem to find it. I'm thinking I'll work with our safety department and we will do a generic risk assessment and document that our standard LOTO practices exempt an electrician from requiring an EWP.

The exemption to work permit fot LOTO in the 2012 eddition stetes that, testing,troubleshooting and voltage measuring shall be permitted to be performed without an energized electrical work permit. Since Voltage measuring is required with LOTO to prove it's absence, LOTO is exempt from energized electrical work permits.

Okay, that makes sense to me. Thanks for clarifying!

The act of opening/closing disconnect devices itself is not energized work. Its not changing wiring in the circuit but operating devices. Plugging in plugs and fuse pulling is where we start splitting hairs especially cutouts, and there are lots of distribution and overhead line work methods that are clearly energized work, but 1910.269 applies and energized work permits are not required. I generally go by the rule if its DESIGNED as a disconnect. Certain disconnect means though where you are plugging onto a bus are inherently arcing fault hazards soarc flash PPE is required though permits aren't. If its load break then arc flash PPE is not required if the 'normal operation' criteria are met.

@PaulEngr

I disagree with your statement -

"The act of opening/closing disconnect devices itself is not energized work.... If its load break then arc flash PPE is not required if the 'normal operation' criteria are met."

If the line or load side of a disconnect is energized then operating that device is absolutely energized work.

The very nature of a disconnect is a fast moving device subjected to mechanical stresses that wear out the components of the disconnect over time (primary contacts, insulators, operating mechanism)...especially under adverse environmental conditions.

At least half of the arc flash damaged devices that I've cleaned up / repaired / replaced in the last 15 years have been disconnects that have hung up when closing / opening, had breakage issues, or had the primary contacts misalign.

Even when operating a device inside an enclosure full PPE should be worn for that application.

If the above is true, then no one using 277 VAC lighting could turn on a light switch without a EWP and proper PPE.

Correct?

Again, there is a difference between work where a permit is required and work that isn't. 70E refers to working on energized equipment in the definitions as making circuit changes, work on energized equipment that is diagnostic in nature as diagnostic work, and more recently operating equipment as 'normal operation' and it looks like under 2018 also 'abnormal operation'. Work permits are only required for one of these four categories. PPE is required for abornmal operation and some diagnostic work. It may or may not be required for voltage checks (depends on if crossing the restricted approach boundary with body parts or uninsulated tools/materials), and is required for applying temporary protective grounding. If disconnects aren't maintained, as with ANY other equipment, they can become hazardous to use. This is the same standard applied to ropes, slings, chains, cables, structures, file cabinets, extension and other cords, vehicle brakes, you name it. A famous OSHA arc flash case occurred at 120 V when an IT employee plugged a damaged cord into a laptop and a similar case occurred with a defective power strip. The injury was to the hands, well under a 15-18" working distance, and frankly no current PPE standard would have offered any protection.

Any defective equipment anywhere should be taken out of service until it is repaired or disposed of. And equipment must be regularly inspected, whether it is electrical or not. There is nothing special about electrical equipment in terms of safety and maintenance.

We have thousands of pieces of equipment and nearly 1/3 of this equipment is fed from a bus way and many fed from MCC. We don't use energized work permit to change fuses but we use Proper PPE and a standardized work instruction. If we are inserting, removing or terminating cable or wire we do a utility interruption request from our facilities group and de-energize the Bus or the MCC (contractors or in-house maintenance). Either way we also use the Job Briefing and Planning Checklist from NFPA or E-Z Power. This equates to a risk assessment/acknowledgment and risk reduction and review process.

If you are opening the breaker to the MCC you should have PPE on. Then keep it on while you are opening the MCC bucket door and taking your voltage measurement. Then the PPE will be required to change the fuse since there is energized equipment still in the MCC bucket and I have seen accidents happen where you come in contact with that. An EWP is not required since no permit is required to open the breaker or the MCC bucket, and the fuse you are changing is de-energized while you are changing it.

Not correct on many levels. PPE should not be required for operating a breaker that has been properly maintained. As per IEEE studies such as IEEE 493 the likelihood of failure during opening is comparable to or less than other workplace hazards that can result in serious injuries or fatalities. Plus this mindset leads us to banning circuit breakers in commercial/residential altogether. Simply stated, its not inherently dangerous. It is more likely to be damaged and requires an inspection before placing back into service after opening due to a fault as per NEMA AB-4 which is quoted by all molded case manufacturers I deal with. Further if not properly maintained, then its impossible to determine proper PPE, as per 70E, so catch-22, you can't safely operate it at all, PPE or not. So failure to properly maintain means 70E doesn't apply.

Doors are another area that is tricky. If there are exposed conductors behind the door then you are right...PPE required. BUT, if not, and even older MCC's have no exposed conductors, then no PPE required because there is no significant hazard. This would be akin to wearing PPE to enter an MCC room or open the outer doors on some NEMA 3R rated gear. Further as per at least the 2014 edition of NEC, all such equipment with exposed conductors, whether it is over 600 V or not, has to be marked with danger labels. So whether shock and/or arc flash PPE is required before opening a door is required to be field marked.

Finally as to PPE while changing a fuse, again it depends on whether or not there are exposed conductors. The conductors in many pieces of equipment are fractions of an inch away from your fingers in many cases but so long as they are insulated, guarded, or inaccessible against inadvertent contact, they are not exposed. Just because you can see copper or the stabs on the top of a disconnect or breaker are energized does not automatically mean it is exposed. Plus even if it is, the required distance is the restricted approach boundary. In the case of 120 V control wiring as an example, the restricted approach boundary means "don't touch it". Many substation panels have nothing more than a flap of plastic over the door mounted equipment for this very purpose.

So

But, according to the NFPA:



Opening up an MCC bucket door or changing fuses would increase the likelihood of injury IF an arc flash were to occur, no?

Rethinking this a bit, let's consider two different cases. The question is, why replace the fuses in the first place? The answer controls which route we are going down.

If the fuses tripped then we're troubleshooting. As part of this task we're going to be doing voltage measurements (and possibly resistance measurements) and thus right out of the starting gate we know that energized work is required. Depending on the task PPE may be required. With MCC's in particular after going through 10 years of OSHA data as well as personal experience over a 20 year period I can't point to a single case of causing an arcing fault by OPENING an MCC door. I know of a couple cases where closing the doors set one off due to prior poor installation/maintenance practices but you can determine these once the door is open. Once the door is open what's the first thing that's going to happen? Yep, test for absence of voltage. With both breakers and disconnects it is not uncommon for a phase to stick closed. And you can test for bad fuses by one of two methods. Either check for resistance across the fuse or check for voltage across the fuse, but the former is a lot safer. And given that a lot of control power transformers and/or electronic things can fool you into thinking that an electrical connection exists when it doesn't, the best way to test is to pop the fuse out and check for resistance.

The next question is when doing this task, can someone cause an arc flash and is PPE required? PPE is required if conductors are exposed. Take a look at the following image:

http://media.fluke.com/images/f-tl175-01c-600x402.jpg

The black probe in the picture leaves about 1" of metal exposed. If someone accidentally sticks the probe in the wrong place or probes contacts that are close together, chances are pretty good that an arcing fault can occur. With probes similar to the red one, there's not enough exposed metal for this to happen. Thus while taking voltage readings, the likelihood of causing an arcing fault is about the same as a visual inspection for contacts. If wires are being pushed/pulled/rolled out of the way, the risk increases and this may warrant PPE. 70E requires shock protection PPE whenever there are exposed, energized conductors. Using touch-safe probe tips as illustrated prevents contact between body parts and exposed, energized parts as well as phase-to-phase and phase-to-ground operator-induced faults. 70E is pretty adamant that voltage rated gloves are the one and only way to achieve this but for truly high voltage work (above 35 kV) gloves are actually prohibited (as per IEEE 516) because they fail to provide enough electrical insulation even as secondary insulation and only hot sticks or bare hands, live line work is allowed. 70E states that some sort of insulation or shock protection PPE is required when working past the restricted approach boundary and using insulated tools certainly meets this requirement. That is also how IEEE 516-2009 interprets it, which is the reference given by 70E as well as OSHA when it comes to approach boundaries.

The second case is replacing fuses to change sizes. In this case the equipment is clearly operating normally and is being updated so PPE wouldn't be required for opening the door or replacing the fuses. Again whether PPE is required or not for testing for absence of voltage depends on the tools and how the subtask is being done.

In either case it is undeniable that for both of the above cases energized work is most certainly required even if the only reason for doing so is to test for absence of voltage. It probably only happens about 0.1% of the time or maybe less but every few years I have personally run cases where either a disconnect blade sticks or a circuit breaker contact sticks shut and the presumed "dead" circuit is definitely live, even if only on one phase. If your experience is that you've never had a circuit breaker or disconnect failed closed, then you haven't been working in the electrical business for very long. Thus the ASSUMPTION that a circuit is energized until tested dead is very true even without considering unusual stored energy scenarios.

This then leads to the question of whether or not an energized work permit is required. First lets consider why it exists in the first place. In the hierarchy of controls, one of the ways of limiting and minimizing exposures to hazards is by administrative procedures. Requiring a permit to do a hazardous activity such as confined space entry, hot work, or energized work adds an extra step to the process and more eyes on it, and an extra check against whether or not the work needs to be done in the first place. Thus the energized work permit is not meant to absolutely prevent the work from being done but to limit it to only the energized work that absolutely must be done.

As such if an energized work permit were to be required for ALL electrical tasks, even those that are being done de-energized (LOTO), the whole purpose of the administrative procedure is destroyed because there is no longer an effective, less rigorous alternative. In other words if an energized work permit is required regardless of whether the work is being done energized or not, then why bother doing it de-energized? That's the whole purpose of the procedure.

For this very reason 70E contains an exception for startup, troublehshooting, and electrical testing tasks because these three tasks can't be done de-energized. So it simply exempts them all carte blanche.

Do NOT lump the three requirements together. There are cases where shock protection PPE is required but not arc flash and vice versa. There are also cases where an energized work permit is not required but either shock protection or arc flash protection or both are required.

This post is somewhat helpful to me.