Subpart CC — the loads on a data center site are enormous and the lines are close.
Generators, chillers, cooling towers, transformers and switchgear lineups. Heavy, expensive, frequently picked over occupied areas, and often near energized overhead distribution — because the substation is being built at the same time.
Crane contact with an energized overhead power line. Subpart CC devotes five sections to it (1926.1407 through 1926.1411) for exactly that reason, and on a data center campus the utility tie work and the equipment setting frequently overlap in time and space.
§ The picks
Standby generators. Heavy, tall, and usually set in a yard adjacent to the utility service.
Chillers and cooling towers. Roof or yard, large wind area, frequently over occupied space.
Transformers. Dense loads, tight tolerances, often placed inside a partially complete structure.
Switchgear lineups. Long sections, awkward rigging points, set inside the building envelope.
Air handlers and fan walls. Large, light, and unforgiving in wind.
§ Power line safety — the three zones
| Section | Situation | Requirement |
|---|---|---|
| 1926.1407 | Assembly / disassembly within the prohibited zone | De-energize and visibly ground, or maintain the minimum clearance distance |
| 1926.1408 | Equipment operation up to 350 kV | Determine the line voltage. Default clearance 20 feet, or use Table A distances if the voltage is known. If neither, de-energize and ground |
| 1926.1409 | Equipment operation over 350 kV | Greater clearances |
| 1926.1410 | Operation closer than the Table A distance | A specific, documented set of encroachment-prevention measures including a dedicated spotter, insulating link, proximity alarm and planning meeting |
| 1926.1411 | Power line safety while travelling with no load | Reduced but still specified clearances |
If the line voltage has not been determined, the clearance is 20 feet — not "looks far enough." Determining the voltage requires contacting the utility, which takes time nobody has budgeted, which is why this gets skipped.
§ Ground conditions
- 1926.1402 — the equipment must be assembled and used on ground that is firm, drained and graded sufficiently, with supporting materials (blocking, cribbing, mats) to achieve adequate support.
- The controlling entity — typically the GC — is responsible for ensuring ground conditions and informing the crane operator of known hazards beneath the setup area.
- On a data center site, "known hazards beneath" means the duct bank. Greenfield campuses are threaded with electrical and communications duct banks, often at shallow depth. Outrigger loads over an unmarked duct bank is a real and repeated failure mode.
Coordinate crane setup against the underground utility drawings, not just the surface grade. On a campus where the electrical infrastructure is being installed in parallel with the structure, the as-builts change weekly and the marked locations may be days out of date.
§ Operator certification and qualification
- 1926.1427 — operators must be certified or licensed, by type and capacity of equipment.
- The employer must additionally evaluate each operator to confirm they can safely operate the specific equipment for the assigned work — certification alone is not sufficient.
- Signal persons must be qualified (1926.1428), and riggers must be qualified for assembly/disassembly and for hoisting personnel.
A certified operator assigned to a machine configuration they have not been evaluated on. The evaluation requirement is separate from the certification and is frequently treated as satisfied by the card.
Full-practice EHS with 70E depth
A CSP with 35 years covering the whole site, not just the switchgear room.
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