Subpart K — temporary power is where the citations are.
On a data center construction site the permanent electrical system is engineered, inspected and largely fine. The temporary system is assembled by whoever needed a receptacle, and it is where people get hurt.
For all 125 V, single-phase, 15, 20 and 30 amp receptacle outlets on a construction site that are not part of the permanent wiring, the employer must use either ground-fault circuit interrupters or an assured equipment grounding conductor program. Not neither, and the AEGCP has specific documented requirements most sites do not meet.
§ The assured equipment grounding conductor program
If you choose AEGCP over GFCI, the standard requires all of the following — and this is why most sites simply use GFCI:
- A written description of the program, available at the jobsite.
- At least one competent person designated to implement it.
- Daily visual inspection of each cord set, attachment cap, plug and receptacle before use.
- Continuity testing of the equipment grounding conductor, and a test that the conductor is connected to its proper terminal — before first use, after repair, after suspected damage, and at least every 3 months.
- Test records identifying each tested item and the last date, maintained until replaced.
An AEGCP declared in the site safety plan with no written description, no designated competent person, and no test records — while GFCI protection is also absent. That is two findings, not one.
§ Sections
| Section | Topic |
|---|---|
| 1926.402 | Applicability — installation safety requirements |
| 1926.403 | General requirements — approval, examination, guarding of live parts, working space |
| 1926.404 | Wiring design and protection — GFCI/AEGCP, grounding, overcurrent |
| 1926.405 | Wiring methods, components and equipment for general use — including temporary wiring at 1926.405(a)(2) |
| 1926.406 | Specific purpose equipment and installations |
| 1926.407 | Hazardous (classified) locations |
| 1926.408 | Special systems — over 600 V |
| 1926.416 | General requirements — work practices, protection of employees, passageways and open spaces |
| 1926.417 | Lockout and tagging of circuits |
| 1926.431 | Maintenance of equipment |
| 1926.432 | Environmental deterioration of equipment |
| 1926.441 | Batteries and battery charging |
§ 1926.417 — lockout and tagging of circuits
- Controls that are to be deactivated during the course of work on energized or de-energized equipment or circuits shall be tagged.
- Equipment or circuits that are de-energized shall be rendered inoperative and shall have tags attached at all points where they can be energized.
- Tags shall be placed to plainly identify the equipment or circuits being worked on.
It requires tagging and rendering inoperative. It does not spell out verification, stored energy release, or a documented procedure. On a data center project — where the gear being worked on may be fed from a temporary source, a permanent source, or both — Article 120 is the standard that actually describes what to do.
§ Working next to live gear
The defining feature of data center construction is that it very often happens adjacent to, or inside, an operating facility. A fit-out crew installing a new data hall is working thirty feet from energized 480 V distribution serving a customer.
Two consequences. First, both 1926 and 1910 apply on the same property, and the crews need to know which side of the line they are on. Second, once any part of the new installation is energized for testing or commissioning, NFPA 70E applies to it — the equipment does not care that the project is not finished.
Physical separation, signage under 1926.200, and a clear, communicated energization status for every piece of gear is the control. More on the energization boundary →
The moment it is energized, 70E applies
Qualified person training for electrical subs, commissioning agents and anyone who will work energized gear on a live project.
Onsite training Bring it onsite