Free checklist
Power distribution unit quarterly maintenance checklist
A quarterly power distribution unit round is short on purpose: it catches the wear items that fail between annual services. This checklist is sized for a tech with a phone. Every item says what to look at and the photo that proves the round happened. Work is commonly verified against NFPA 70B, NEC (NFPA 70). Confirm the edition your authority having jurisdiction has adopted.
The checklist
Every item, and the photo evidence it needs
The photo count on each row is what RTI would require before the item can be submitted. Work the list here and watch the gate hold, or load it into RTI and let it enforce the real thing.
Approach and labeling
Nameplate ratings and arc-flash label read on the front
Nameplate kVA, input and output voltages and main breaker rating readable for the load checks, arc-flash label legible, a missing or faded one reported to the owner.
Emergency power off guard and label checked where fitted
Guard in place and unbroken, label legible naming what it shuts down; the button is never pressed to test it, since it drops every load at once.
No photo
Status and load
Front-panel status and alarms read
Metering display active, no standing alarms or fault flags, input and output within the unit's normal indication.
Per-phase load checked for balance
Each phase read at the metering, not just the total, imbalance between phases noted for follow-up.
Highest phase current compared with the nameplate ratings
Most loaded phase on the metering display compared with the main breaker rating and the transformer rating where fitted, loading close to either reported to the owner.
Output voltage and neutral current read on the display
Output voltage on each phase within the nameplate range and neutral current noted where the display shows it, a neutral running high against the phases flagged.
Branch circuit monitoring alarms reviewed where fitted
Each branch threshold set against its breaker rating, no branch in high or overload alarm, and alarm history read for circuits creeping up since the last round.
No photoInput source and transfer status read on dual-input units
Both sources shown available, the static transfer switch on its preferred source, and any transfers since the last round read from the event log.
No photo
Cooling and enclosure
Cooling fans and filters checked
Fans running, intake filters and louvers clear, air moving through the section with no hot-smell or discoloration.
Branch breaker positions verified
Breaker on/off state and labeling matched against the panel schedule, nothing tripped or fed from an undocumented position.
Output cable entries and strain relief checked
Output cables or conduits leaving the unit secured at their entries, bushings and strain relief in place, nothing pulled tight or chafed on an enclosure edge.
Thermal scan
Energized-work controls in place before the thermal scan
Covers removed only as the site's energized-work procedure allows, or scanned through IR windows, by a qualified person in PPE from its arc-flash risk assessment.
No photoConnections scanned under load with the thermal camera
Breakers, lugs and bus joints imaged while energized, any warm connection flagged against its phase mates on the same load.
Close-out
Covers refastened and front door latched after the scan
Every cover or dead-front taken off for the scan refastened with all its screws, front door closed and latched, nothing left inside the unit.
Phase loading and alarms reported to the owner
Per-phase currents, the most loaded phase, branches near their rating and any alarms sent to the owner, naming loads that could move to even the phases.
No photo
What usually sends this back
The failures are almost always the evidence, not the work
- Load read only at the main, so one phase quietly running hot goes unnoticed while the total still looks fine.
- Thermal scan skipped because the covers were left closed, and a loose lug cooks undetected between visits.
- Intake filters blinded with drywall dust from ongoing work in the room, so the cooling fans run the section hot.
Verified against
Common questions
6 answers
- What does this power distribution unit quarterly checklist cover?
- 15 items across 5 sections, covering approach and labeling, status and load, cooling and enclosure, thermal scan, and more. Each item spells out what the person walking the job is actually looking for, not just a box to tick.
- Who should run this inspection?
- The electrician or facilities tech on the quarterly electrical round.
- When in the schedule should this walk happen?
- Every quarter, energized, catching load imbalance and hot connections before they turn into an outage on the loads downstream.
- Why do these items ask for a photo?
- 10 of the 15 items call for photo evidence, 11 photos in all. A checklist answer without the photo is a claim; the photo is what makes the record worth something in a dispute and lets a reviewer approve work without re-walking the job.
- What most often fails a power distribution unit quarterly inspection?
- Load read only at the main, so one phase quietly running hot goes unnoticed while the total still looks fine. Thermal scan skipped because the covers were left closed, and a loose lug cooks undetected between visits. Intake filters blinded with drywall dust from ongoing work in the room, so the cooling fans run the section hot.
- Can I use this checklist in RTI?
- Yes. Start a free RTI workspace, build this list as a checklist, and the Photo Gate holds the submit button until every mandatory item is answered and its photos are attached. Approved inspections roll into a branded turnover package with a tamper evident audit trail.
Run it with the Photo Gate
A checklist nobody can submit half-finished
Load this list into RTI, stick a QR tag on the area it covers, and the submit button stays locked until every mandatory item is answered and the 11 required photos exist. Approved walks roll into a branded turnover package with a tamper evident record behind every line.
See all 508 checklists · 6741 items and 5984 photo requirements in total.