August – September 2022 Q&A
Q: Is it ever OK to put a man basket on a crane? My understanding is that OSHA 1926.1400, “Cranes and Derricks in Construction,” states doing so is prohibited.
A: For our readers, the rule you are referring to is 29 CFR 1926.1431(a), which begins, “The use of equipment to hoist employees is prohibited …” The rule goes on to list the basis for exceptions. For line construction, an exception centers around two provisions: the need for access and safety. In a transmission corridor, there are often parallel circuits. An articulating boom in a conventional bucket truck would put the boom elbows in hazardous proximity to adjacent circuits. Additionally, in the past, crane booms had reach that could not be matched by conventional bucket trucks.
Things have changed, and Incident Prevention has been warning readers for years that these exceptions are diminishing. So, here is what to watch for.
First, the manufacturing industry has kept up with the rules. Several companies, such as Manitowoc and Altec, now make telescoping booms that are dual service, being both a crane and an aerial platform device meeting the ANSI A92 standard for elevated platforms. The unit can be configured as a multipart conventional hydraulic crane but comes with a man basket with radio-frequency controls for operation from aloft. There are expected to be gray-area issues with OSHA at some point because the man basket can be used with a crane operator, which makes it a crane performing as an aerial lift. The A92 compliance requires that when the basket is occupied under the A92 standard, the controls are operated by the basket occupants and no one is in the crane seat except in the event of an emergency or for rescue purposes.
From a strict OSHA compliance standpoint, if you are using one of these dual-service units with an operator in the seat, you will be in violation of the exception to 1926.1431(a). The rule states that one of the exceptions is “where the employer demonstrates that the erection, use, and dismantling of conventional means of reaching the work area, such as a personnel hoist, ladder, stairway, aerial lift, elevating work platform, or scaffold, would be more hazardous …” Since the crane you are using is also an A92 manlift, the operator in the seat makes use of the crane a violation of the prohibited lifting of personnel.
You might ask, what’s the difference? It’s the same machine, right? However, you would be ignoring what OSHA sees as an obvious increased hazard: a remote operator instead of operation from the basket. In any case, similar or not, the OSHA standard is prosecuted on the very precise wording of the standard, the intent of the standard and the expectation of compliance. In addition, keep in mind that when the platform is configured and operating as an A92 manlift, it is not a crane nor is it regulated by the 1926.1400 standard. This will eventually be another contested employer/OSHA issue, but for now it’s the best interpretation of the rules.
Q: We were recently advised that it’s hazardous to ground an excavator to a substation ground while the excavator is working outside the substation ground grid. However, no one could explain why this is hazardous. What is iP’s opinion?
A: We agree that it’s hazardous, and here is why. For starters, we rightly must assume the very worst-case situation. OSHA opines in the standards that whatever the situation, if the risk can’t be quantified, it must be assumed to be hazardous, so we must do the same.
The ground grid under a substation is intended to put everything within the boundary of the grid at the same or very near the same potential. As you leave the boundary, the resistance of the earth between the grid and its very low-resistance deep-earth connection and the point of contact of the earth outside the grid will be at a different potential. There is a good possibility that the near earth outside the extent of the grid will be very close to the same potential, but keep in mind that the station is typically built on compacted fill dirt. At some distance, the earth away from the station is natural earth of some unknown conductivity. Some readers will immediately think of the substation fence. Not to worry, fencing and the earth outside the fence are considered safe to touch when the difference in potential is an arm’s length. In this case, we are talking about a somewhat greater distance.
Now that we have established that the earth, some distance away from the low-resistance ground grid, is at a different potential, consider what happens if we ground our excavator to the substation. Having grounded the excavator to the grid, the excavator is at the same potential as the station sitting on earth that is at a different potential. Now, a worker standing on the earth at one potential while touching the excavator at a different potential is at risk. The hazard is compounded if the substation ground is loaded with an intermittent ground current from a fault or even if it is continuously exposed to ground currents from induction. We consistently find current on ground paths of 30-50 amps in higher-voltage stations like 345-500 kV.
The next question, then, is how do we keep from getting shocked when touching the excavator that becomes charged by induction from the overhead 500-kV circuit? There are two practical solutions and one not-too-practical solution. Not too practical is grounding the excavator with a temporary installed ground rod. It’s not very practical because tethering a mobile excavator is a tripping hazard. So, here is the first practical solution: When the excavator boom is in the earth, it is in contact with the ground and very unlikely to gather a charge from nearby circuits. The second practical option? Don’t touch the excavator.
A final note: IEEE Standard 1048 Amendment B, which is now under balloting, discusses barricading and establishment of an equipotential zone. This may not always be a practical solution for moving vehicles such as an excavator, but it may be considered in some cases.
Q: What policies are you aware of that address crane/drill rig work (OSHA 1926.1410) in proximity to energized conductors, specifically transmission voltages? The regulations are fairly clear, but I’m wondering if anyone has a working field policy that allows for crane work closer than Table A around energized transmission conductors.
A: If the crane operator is not an electrically qualified operator (i.e., a lineworker), the operation must comply with 1926.1400, “Cranes and Derricks in Construction.” All those requirements are established to prevent the crane from entering that unqualified operator clearance. If we have an operator who is an electrically qualified person, we are purposely bringing that crane boom inside the limits imposed on an unqualified operator. So it stands, then, that if you are “crane” working for power-line work/pole foundations with an electrically qualified operator, the operator of the crane must be 1926.1400 certified as an operator, but you are the power company. That makes the 1926.1400 requirements for fewer than 20 feet sort of moot since you can figure out the limitations yourself. We still must follow all the traditional safety protocols we have always followed to prevent the boom from encroaching into the minimum approach distance. We also have the obligation that the operator, who is a lineworker, must be a qualified and licensed crane operator. The drill rig is a completely different story.
A drill rig that does not hoist and lower by means of a hook and cannot horizontally move a suspended load is not a crane, so choice in the capabilities of your pressure digger matters. Paragraph 1926.1400(a) lists the equipment considered by OSHA to be a crane, and the list includes a dedicated pile driver. The pile driver is included because the pile-driver boom has a hook on a winch that is designed to lift piles vertically to place them in the pile driver. If a low drill is equipped with a hook to manipulate the auger heads for the kelly-bar installation, following the pile-driver logic, the low drill would be considered a crane and require a crane operator. If the operator is also an electrically qualified lineworker, the rules would be the same as for a crane.
The low-drill or pressure-drill rig, absent a lifting hook, is not a crane and doesn’t need a 1926.1400 qualified crane operator. The operator must be certified by the employer as qualified.
Q: We have a 10-foot-by-12-foot subterranean manhole with a completely removable cover for ladder access. The space will contain three aerial transformers, with URD insulated primary leads feeding into the aerial transformers and tape-insulated secondary bushings. Is this considered a vault or an enclosed space?
A: Your space is a vault covered under OSHA 1910.269(t) as well as an enclosed space covered under 1910.269(e). See the definitions at the end of 1910.269, also included below, to help keep them properly classified as you work your way through.
“Enclosed space. A working space, such as a manhole, vault, tunnel, or shaft, that has a limited means of egress or entry, that is designed for periodic employee entry under normal operating conditions, and that, under normal conditions, does not contain a hazardous atmosphere, but may contain a hazardous atmosphere under abnormal conditions.”
“Vault. An enclosure, above or below ground, that personnel may enter and that is used for installing, operating, or maintaining equipment or cable.”
“Vault” basically describes the type of facility whereas “enclosed space” describes a condition that can occur within a vault, manhole or sometimes even a trench. The cover itself doesn’t really qualify the space. Since all vaults are designed with the expectation that people will work in them, they may also be enclosed spaces, especially if they have ladders or steps built in, signaling intention for periodic entry.
What makes it an enclosed space is the part of the definition that reads “under abnormal conditions.” This is interpreted as a cable or device fire that creates a toxic environment via the smoke, electrocution or burn injury from a flash. All of these are hazardous atmospheres that immediately change the space to a permit-required confined space. For this reason, an attendant is not allowed to enter an enclosed space where these potential hazards are present (see 1910.269(e)(7)).
An attendant is not precluded from occasionally entering a manhole or vault under 1910.269(t)(3). In that paragraph, the consideration also includes an assessment of the space if it has energized cables. A vault can be an underground space with cables that pass through, splice or change direction. Once it’s closed up, you won’t be going in again. An enclosed space may be a splicing vault; have other equipment or be a space that has metering or where workers will routinely enter; or the space is configured with the expectation that workers will periodically enter for maintenance or operations. If we don’t look at and use the definitions, trying to figure this out can be as gray as an area can get.
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