When a PDU loses neutrals quietly
Neutral impedance rises long before breakers complain. Here is how one Seoul campus caught it during a routine infrared round.
Neutral issues rarely arrive with fireworks. More often, technicians notice odd harmonic signatures on monitoring graphs or feel unexplained warmth on feeder bundles during evening rounds. The Gangnam site referenced here scheduled quarterly infrared baselines after a vendor swap, then layered handheld reference probes on the same day each quarter so comparisons stayed honest.
During the third pass, a PDU serving a lightly loaded IDF cluster showed a five-degree delta against its twin, even though loads were symmetrical on paper. Instead of resetting breakers, the crew opened the activity log, confirmed recent cabinet moves, and traced a mis-torqued neutral lug hidden behind a cable manager. The fix took twenty minutes once found, but the search discipline took months to engrain.
VaultGrid Academy replays this sequence in the Busway thermal imaging rounds with intentional decoys so participants practice narrating uncertainty without rushing to conclusions. The editorial desk shares these anonymized timelines so readers can borrow language for their own shift briefings.
If your hall lacks a neutral monitoring tap, the article appendix lists three procurement-ready sensor families that play nicely with common BMS cards—informational only, not an endorsement.