From my understanding, energized work is forbidden with the exception of the three following clauses (4.3.2.2):

1. Additional hazards or increased risk (4.3.2.2.1)
2. Infeasibility (4.3.2.2.2)
3. De-energizing at less than 50V (4.3.2.2.3)

If the energized work falls within one of the three exception clauses, then an energized work permit (4.3.2.3) must be issued except for the exemptions to work permit found in clause 4.3.2.3.3.

A qualified worker can then undertake energized electrical work within the limited approach boundary wearing the appropriate PPE.

I have personally not found up to now a clause in the Z462-12 that indicates a distinction between energized tasks. Lists of common tasks are included in Z462-12 table 4A.

When establishing an electrically safe work condition lockout procedure must be used to de-energize equipment. Most lockout procedures involve breaker operation, switch operation and breaker racking.

How can lockout procedures be executed if energized work such as breaker operation, switch operation and breaker racking are not in the exception clauses of 4.3.2.2.

In other words, how is an electrically safe working condition to be achieved if the lockout procedure to attain to the safe working condition is considered to be energized work and it is forbidden because it doesn`t fall under the exemptions found in clause 4.3.2.2?

thanks!

I don’t think you must see that kind of energized work as forbidden. It is more like until you verified that it is de-energized you must assume it is NOT so wear appropriate PPE.

In the NFPA70E 2012 edition annex G Sample lockout/tagout procedure, there is no mention of needing a energized work permit.

Annex J figure J.2 is a flow chart that shows that when you want to lockout/tagout equipment you must follow the lockout/tagout procedures the energized electrical work permit is not required.

Look at the exception clause that was added just after 4.3.2.2 in the 2012 edition. Previously the arrangement of the paragraphs was significantly different. You had section 2 which specified that if LOTO is being performed, follow section 3. If it is energized work, follow section 4. There were two issues and thus the changes in the 2012 edition. First, the previous edition only evoked the energized work permit for shock hazards. Arc flash hazards were not considered. Second, the rules specific to the hazards were contained in section 4, not section 3. Strictly speaking although hazard analysis was required in section 2 regardless of the work, there were no corresponding rules for dealing with hazards in section 3.

Thus the material in section 2 was moved to section 4. Arc flash boundaries were also added to the energized work rule. At this point section 3 now stands alone since it only applies more or less in conjunction with section 4 while de-enerigizing activities are going on. This solved the issues, at least partly. The trick here of course is that you have to interpret when the hazards exist (see definitions section for arc flash hazard, and exposed definitions for shock hazards). The shock hazard definitely does not exist while operating a switching device with the doors closed and latched for instance. The arc flash hazard MAY exist but we get into the interpretational soup of "interaction". Appealing to the task tables which is what the definition seems to suggest is no help either. So there is no way out using the sections that you have looked at so far.

You can't de-energize to perform de-energized work unless at some point the work is actually energized. Previously this did not arise because you were either performing LOTO and thus ignore the energized work permit issue, or you are performing energized work in which case either it applies or the diagnostic work exception(s) apply, or you use a tortured interpretation of the diagnostic exception such as calling all switching activities "startup" work. So a new exception was added right after section 4.3.2.2 which I believe is supposed to "fix" the problem of merging section 2 into section 4 material by allowing an out for energizing and de-energizing equipment (switching).

At least that's my interpretation...the exception is one of the most convoluted and impossible to read, tortured paragrpahs in the entire standard. I submitted a comment on this paragraph to make it more readable for the 2015 edition but my comment was rejected by the committee. Apparently they like the lawyerized version that is impossible to read. The complete text of the exception for you to try to analyze is as follows:

"Exception: Where a disconnecting means or isolating element that has been properly installed and maintained is operated, opened, closed, removed, or inserted to achieve an electrically safe work condition for connected equipment or to return connected equipment to service that has been placed in an electrically safe work condition, the equipment supplying the disconnecting means or isolating element shall not be required to be placed in an electrically safe work condition, provided a risk assessment is performed and does not identify unacceptable risks for the task."

My interpretation is as follows:
Clause 1: "Where a disconnecting means or isolating element that has been properly installed and maintained is operated, opened, closed, removed, or inserted to achieve an electrically safe work condition for connected equipment or to return connected equipment to service that has been placed in an electrically safe work condition,"
In other words if you are place/return equipment in an electrically safe work condition.
Clause 2: "the equipment supplying the disconnecting means or isolating element shall not be required to be placed in an electrically safe work condition"
In other words, ignore the energized work permit rule.
Clause 3: "provided a risk assessment is performed and does not identify unacceptable risks for the task."
Risk assessment is required for this task. Risk assessment is later required for ALL energized tasks anyways. This clause is redundant.

If the exception consisted simply of clause 2 with just a little more context, it would have been far more clear.

The alternative would be to issue an energized work permit every time for all switching tasks. The clear reason for doing so would be infeasibility, or perhaps to claim that doing a task de-energized is less of a risk than the risk that de-energizing itself would impose. Although there are many times where I believe that the latter interpretation is in fact correct such as when de-energizing high incident energy panelboards vs. landing plug-in breakers, this should be the exception rather than the rule.

However from a very practical point of view, let's consider the result. If we in fact require an energized work permit for ALL electrical work, whether it involves energized work or de-energizing to perform the work, then issuance of the permit will become automatic and routine. Dare I say it, nobody is going to be paying any attention whatsoever to the permit at all. The entire purpose of the permit in the first place is an administrative control...to require someone to spend the time determining whether or not the task can be done de-enerigized in the first place. And second, that the second party which is actually authorizing the permit is management and is acknowledging their responsibility in allowing what is known to be a hazardous task to occur, and that there are no practical alternatives. Someone in the decision loop should be taking a look at the criteria for the hazard and making an interpretation that there is just no good alternative. If we just start requiring energized permits for all tasks, then that particular aspect of the rules will be completely ignored. Issuance of energized work permits should definitely be the exception and not the rule. That is clearly not the intent.

So...choose your poison. Either allow a "4th exception" for switching tasks, which appears to be what the exception paragraph means, or torture the "startup" exception. Regardless, from a practical point of view, this is necessary.

I can`t find this exception in the CSA Z462-12. It is in the NFPA 70E 2012 though.

1. No permit needed if you have remote open/close functions. At this point you are operating equipment and not within either the arc flash or limited approach boundaries so no PPE needed. Not H/RC 0...none needed. Once you go to test (step 5), this is diagnostic work. There is already an exception for this in both 70E and CSA Z462. This exception has been there for a long time. It follows the energized work permit rule. So no, no permit needed for this. When it comes to applying grounds though, this would definitely be altering the circuit so no exception there. The greater hazard rule definitely can apply because working live on medium voltage is far more risky than installing the ground and taking the relatively low risk one time, so both this and the infeasibility clauses apply. At this point the circuit tests dead though so technically I'm not sure if you can even say that this is doing "energized work" since it has already been tested dead. As you know the purpose of installing grounds is to prevent induced voltages, another layer of protection against accidental energization even naturally occurring ones (lightning), and to drain off any residual charges in the system to provide an equipotential work zone. If you follow the Z462 procedure, you test first then ground. I have no idea what to do if you actually detect induced voltage under Z462. Under IEEE C2 (NESC) and similar procedures intended for utilities, you ground first, then test.
2. Standing energized work permits are even mentioned in the 2012 edition of 70E at least. The key is to ensure that you apply the same amount of scrutiny that you would apply to the energized work permit. I know of several plants in SK that have standing permits specifically just for the 120 V controls, and have implemented a similar one here.
3. If you have remote trip, I don't know what additional risk there would be for remote close as well. Many plants have what is commonly called a "mimic panel" and with todays microprocessor controlled relays, I can even plug in a battery operated wireless dongle into the front of the relay and sit in my truck outside the room and operate the breaker without being anywhere near it. The safety concern here is if you close when it is unexpected, but that's the reason we have something called lock out procedures.
4. Item 5 is incorrect strictly speaking from a safety point of view. The failure rate for disconnects is one to two orders of magnitude lower for disconnects over circuit breakers. The 70E Technical Committee reduced the H/RC value based on the lower likelihood. However this is invalid from the start. The arc flash hazard is not reduced. Wearing under-rated PPE has about the same risk if an arc flash were to occur as wearing no PPE at all. In fact Doan and a couple others have published a paper testing this and found that although PPE worn according to calculations in IEEE 1584 works 100% of the time (so far), there is only a 50% chance of avoiding injury by following the tables with reduced PPE. Thus, the correct H/RC is either "4" or "0", not "2". Better yet, do your own study. But for the purposes of illustration, we can stick with the tables.