Tag: Q & A

Q: We are contractors with a truck grounding question for work inside substations. Working within a proper clearance, the generation and transmission cooperative (G&T) that owns the transmission circuit coming into the substation believes 4/0 equipment grounding is needed, while the consumer utilities operating the substation say 1/0 or 2/0 is required. We sometimes are required by the G&T to use double 4/0 to meet the required available fault current. Can you explain the disparity in requirements? Also, do we meet the OSHA requirements if we use the 1/0 or the 2/0 for equipment grounding...

Q: We have been reading OSHA 29 CFR 1910.269 regarding two-man work, but we cannot find a definition for “routine switching.” We are under the impression that a trained troubleshooter can replace blown fuses in cutouts without a second man. Since it is not specifically mentioned in the exceptions, do we have this wrong? We have old porcelain cutouts on our 4-kV system where you cannot remove the door with a stick and must grab it with your hand, putting the worker within the minimum approach distance of the energized 15-kV overbuild above. This is especially an issue for us at night and in storms....

Q: We have received some pushback from clients when setting up transmission pulling on EPZ mats that are constructed over crane mats, covered with galvanized cattle panels, overlapped, stapled down and bonded together. We follow a model passed down through our parent company’s safety research committee. Our clients have asked if the installation is certified. We did some research, found ASTM F2715 and are now wondering if that is what we should be doing. Can you help?

Q: Why do some experts say ground rods won’t work to trip a circuit? A: The experts say this because they are right depending on the conditions, which we’ll soon discuss. But let’s start with a definition of the idea of “remote ground” as the point at which we connect a protective system to earth. The lower the resistance of that remote ground connection to earth, the more current flows and the faster a fault clears. So, what we should be doing as a rule is using the best available ground to remote earth. The problem is that we often overlook a key element in this debate, which is that the ground...

Q: We don’t provide self-rescue equipment for lone workers, but we recently heard that OSHA is requiring self-rescue equipment as part of the General Duty Clause. Are you familiar with this? A: This is a complex question, part of which might border on legal arguments. Incident Prevention relates legal opinions to our readers from case outcomes that we are familiar with, but in practice avoids rendering advice or opinions that may border on legal terms. The rescue requirements in the OSHA rules do not address self-rescue. Many employers address self-rescue in part based on their interpretation...

Q: We have a crew performing pole change-outs with the line energized. They are suspending phases with a link stick and digger derrick to provide more clearance between phases to install new poles and hardware. The question is, can the operator leave the controls with the phase lifted? We thought they could, but it seems there has been a change to OSHA 29 CFR 1926.1417(e). A: The good news is that you cited the wrong rule. Pole change-outs fall under the 1910.269 operation and maintenance rules. You cited the rule for construction (OSHA 1926). The operation and maintenance rule – found at 1910.269(p)(1)(iv)...

Q: I read what was written about an air gap for worker protection in the June-July 2020 issue of Incident Prevention magazine, but one of our engineers who sits on a National Electrical Safety Code advisory committee brought something to my attention. NESC C2-2017 444.2 states,  “Air gaps created (e.g., cut or open jumpers) for de-energizing equipment or lines for the purpose of protecting employees shall be tagged and meet minimum clearances as specified in Table 444-1 or separated by a properly rated insulator.” What are your thoughts on this matter? A: Thanks for your question. Our...