I believe it is safe to say that the amount of energized electrical work continues to decrease dramatically with the increased awareness regarding electrical safety and use of safe work practices.

This week’s question is about how much energized electrical work is performed.

Both NFPA 70E and OSHA required work to be performed in a verified de-energies state. The exception to this is if it can be demonstrated that de-energizing introduces additional hazards, increased risk, is infeasible or performing functions that require the electrical equipment to be energized such as voltage testing, trouble shooting, IR scanning etc. It is difficult to create an extensive list of all possible exceptions but some may include electric utilities "live line" work and other parts of the system such as generation may also be an exception as well as other critical/emergency systems.

Here is this week's question:

Other than voltage testing or troubleshooting, IR and others listed above, do you/company/client perform any energized work?
Yes
No
Some - but very limited
Doesn’t apply

Need to be careful of what the definitions are upon which there seems to be quite a bit of confusion. When you say energized work, many people interpret that to mean the power is on, not limited to specific tasks. And that's part of the trouble.

Plus it depends on the equipment. For instance can you "de-energize" a battery? How about a capacitor? What about generators? Is it "dead" if remove the prime mover? What about if we interrupt and block out the excitation circuit? What about induced voltages and/or currents? And if it is "de-enerigzed", with respect to what reference, particularly when considering DC? That's just the tip of the ice berg. Anyone who thinks you MUST do all work while de-energized has never considered a simple battery. This definitely falls into the "feasibility" category.

Then we get into control power vs. main power. Is it de-energized with control power off and main power on? What if it's only on one side of a device such as opening and locking out a breaker and then removing or installing wiring on the load side? What about situations where we have removed main power but not control power such as the common case of common control power in an MCC or when PT's (and maybe CT's) are energized in a breaker control cabinet but not the main power? Is removing control power but leaving main power sufficient for some work such as work inside a breaker control cabinet? How about the act of de-energizing/energizing using control switches or operating breakers and/or disconnect switches? And if you say it can't happen or is very rare...I'm reminded of two cases. First one was an electrician around here that was the poster child for an arc flash. After several attempts to reset a breaker by operations (no comment on the practice) and by the electrician they finally started testing and found a burned up motor. After lockout and replacement when the electrician went to re-energize the circuit, the breaker blew apart and created a significant arc flash on a very high fault current bus. Visual inspection of the breaker wasn't performed. Another case in the OSHA logs indicates that a previous "repair" attempt on a panelboard wedged sheet metal in the panels of a panelboard to cover the empty holes without securing it. The breakers were used for lighting control (hopefully switching duty) and later when the breaker was operated to cut the lights out for the night, the sheet metal fell back into the bus and badly injured the operator rather than the electrician who did the poor maintenance job.

Not too many years ago of course we had the push buttons with the plates or covers so that we could hold in the stop button to interrupt control power and "lock it out"...OSHA still requires "main power" to be disabled but now we're starting to see VCB's with magnetic actuators on them. You HAVE to supply power both to energize and de-energize, and the breakers are often coming with capacitive trip devices on them for this reason. Is it time to revisit the "main power" lockout requirement, whether or not OSHA adopts it since 70E is used in so many other jurisdictions? We just did this with allowances for permanently mounted voltage measurement devices.

Finally, need I bring up generation, transmission, and distribution systems in which the whole de-energized work argument is not only probably a fool's errand at this point in our culture but the fact is that the equipment is specifically designed for and operated while energized. It is common practice to connect and disconnect even outright jumper wires (albeit with gloves or hot sticks) while energized, whether or not saddles and similar line attachment devices are used. Changing insulators and lightning arresters and similar accessories is also typically done by literally lifting an energized line and placing it to the side, changing the accessory, then moving the line back again. Normally all of this is perfectly safe but once in a while something goes wrong. I'm reminded particularly of a ground man on a local crew near here that was replacing an old copper overhead line that had rotted out. When the lineman went to lift the line, it disintegrated in his hands. The lineman wasn't hurt but when it came apart the line fell and struck the ground man on the way down...while energized.

Finally it references voltage testing all over it. When it comes to DC this changes little since the standard way to measure DC current is with a shunt if at all possible. But what about iron core or Rogowski coil CT measurement devices? The argument often made is that since you have to wrap the device around something that it is manipulating the wire/cable/busbar but the exact same argument can be made in many cases for voltage measurement. Arguments have been made as to manipulation of the conductors being the issue...many times manipulation of the conductor is also necessary with voltage measurement. Let's not forget while we're at it that many times the oxide layer has to be scraped off or the probe might in some rare cases have to be stabbed through the insulation to get a reading...both of which are teetering on the edge of crossing over from diagnostic to non-diagnostic energized work.

And let us not forget that depending on equipment design and/or installation practices that opening and closing doors MIGHT be considered energized work. I'm reminded of the outer doors on most drawout switchgear which is quite literally barely a dust cover and does really nothing. Opening or closing that door doesn't expose anyone to inadvertent contact in many cases. There are arguments raised about pinched cables and with drawout gear, obviously that almost always literally can't happen. It also can't really effectively happen if the cabling is terminated properly in a neat and workmanlike manner with a reasonable maximum amount of slack. It is quite a different story with what I normally see where panduits are jammed full where the control cables are looped back and forth 4 times, and roughly half a spool of power cable is coiled up in the bottom of the bucket or half hanging out the door. My suggestion with doors is this: follow NEC to the LETTER. Any door which on opening creates an exposed conductor hazard should be marked "DANGER" (for >=600 V) or "WARNING" (for <600 V) ...EXPOSED CONDUCTORS...KEEP OUT or something similar. That way those of us that service the equipment can determine before opening the door whether or not we need the PPE on or if we can at least open the door and get a good visual inspection done before getting the PPE out, and we can at least see what we're up against without trying to peer through a dark tinted hood.

Anyways...I HATE the energized work definitions. They just leave way too much open to interpretation by people who are decidedly not qualified to do the work and not qualified to pass judgement on the safety of the task because they are not trained and knowledgeable about the equipment construction, operation, and maintenance, yet make decisions on doing just that.

We no longer expose energized components, solely for the purpose of data collection.
We do collect data from energized equipment if the covers have been removed for other 'allowed' reasons. for example, we will 'work near' exposed energized components, during IR scanning, because it is infeasible to do otherwise.

Thanks for your comments Paul and JBD!

I attempt to keep the Question of the Week short and simple but sometimes that does not always work. Especially for this week based on your comments. I added some clarification but this is still a difficult one to completely define so we'll go with the "general intent" of the question - a nebulous response.

Thanks for all of your contributions.

Hi All

I have to agree with Paul's comments particularly at the end and that is with how we define energized work. Especially the 2 categories- diagnostic and repair. Up here in Canada when CSA Z462 first hit the streets in early 2009 this brought on mass confusion, unfortunately with those unqualified and who would never pick up a test instrument or hand tool. I had a client here where there was actually a work stoppage because someone though it was unsafe to test with an instrument with the power on. It has improved in recent years as better education is out there and people have a better perception. However there was a campaign up here in Ontario a few years back on "Dont Work Live". Although the intentions were good of the campaign it did cause some confusion

On a related note, I'm curious what the perspective is regarding racking in or out MCC or switchgear breakers? If this is being done to provide a physical open for LOTO, and no work is being done on the breaker, is this still "energized electrical work"?

Sooner or later if you inset an MCC bucket onto a live bus, it will set off an arcing fault on the bus. They are way too flimsy and depend far too much on handling while blind to do it safely. With draw out breakers some designs have long enough stabs that if it misaligned it can fold over. Not all.