What does this dry-type transformer quarterly checklist cover?

14 items across 5 sections, covering before the round, cooling and temperature, sound and load, terminations and grounding, 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 facility electrician on the quarterly electrical round, working entirely outside the enclosure with the unit energized.

When in the schedule should this walk happen?

Every quarter, scheduled for a loaded part of the day so the reading reflects real heat, not an idling unit.

Why do these items ask for a photo?

10 of the 14 items call for photo evidence, 12 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 dry-type transformer quarterly inspection?

Louvers half-blocked by pallets or boxes stacked against the enclosure in a tight electrical room, so the winding runs hot all summer. A rising hum or buzz noted by the operator but never logged, so a loosening core clamp is only found after it rattles loose. Termination heat never scanned because the covers stay on, so a warm lug isn't caught until it discolors.

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.

Free checklist

Dry-type transformer quarterly maintenance checklist

A quarterly dry-type transformer 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, NETA maintenance testing standards. Confirm the edition your authority having jurisdiction has adopted.

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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.

Before the round

Nameplate and arc-flash label legible on the enclosure
Nameplate kVA, primary and secondary voltages and tap table readable, and the arc-flash label present and legible, with a faded or missing one reported to the owner.
Enclosure left closed and approach PPE set by assessment
Every panel stays fastened, secondary current is taken at the downstream panel's metering or a clamp point, not inside this enclosure, and PPE comes from the site's arc-flash risk assessment.
No photo

Cooling and temperature

Ventilation openings clear on all sides
Top and bottom louvers unobstructed, no storage against the enclosure, room airflow moving through the transformer rather than around a blocked face.
Enclosure and winding temperature within normal range
Any built-in winding temperature indicator read against the last round, and the enclosure skin read with an IR thermometer for the load it's carrying.
Room ambient temperature read beside the unit
Ambient reading taken near the transformer and compared with the last round and the nameplate ambient rating, with any room exhaust fan or louver serving the space running.
Temperature controller and cooling fans checked where fitted
Where a controller or fans are fitted, no alarm or trip showing, fans running as the controller calls, and any alarm history logged; units without them record none fitted.
No photo

Sound and load

Hum and mechanical sound compared to baseline
Steady 60-cycle hum without a new rattle, buzz or intermittent chatter that points to loose laminations or a slack clamp.
Enclosure anchorage and conduit entries checked
Enclosure anchored level on its pad or bracket, and conduits entering through flexible connections rather than rigid runs that carry hum into the structure.
Load current read at the secondary
Phase currents read at the downstream panel's metering or a clamp point outside this enclosure and compared against nameplate rating, no single phase running far above the others.
Secondary voltage read where metering serves the unit
Voltage at the downstream meter compared with the nameplate secondary at the tap on record, a steady high or low reading reported for a tap review at the outage.
No photo

Terminations and grounding

Accessible connections scanned for heat
Thermography or a non-contact scan across visible primary and secondary terminations, no hot spot standing out against neighboring lugs.
Ground and bonding connection intact
Enclosure ground and the equipment grounding conductor landed tight and unbroken, no corrosion or paint under the lug.

Enclosure and reporting

Enclosure panels and vent screens intact
Every side and top panel fastened, vent screens whole so nothing can be pushed through onto the coils, and no dents closing the cooling gap.
Round findings reported to the owner with readings
Any warm lug, new noise, high ambient or unbalanced phase reported to the owner with the reading or image and carried into the next outage scope.
No photo

What usually sends this back

The failures are almost always the evidence, not the work

Louvers half-blocked by pallets or boxes stacked against the enclosure in a tight electrical room, so the winding runs hot all summer.
A rising hum or buzz noted by the operator but never logged, so a loosening core clamp is only found after it rattles loose.
Termination heat never scanned because the covers stay on, so a warm lug isn't caught until it discolors.

Verified against

Common questions

6 answers

What does this dry-type transformer quarterly checklist cover?: 14 items across 5 sections, covering before the round, cooling and temperature, sound and load, terminations and grounding, 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 facility electrician on the quarterly electrical round, working entirely outside the enclosure with the unit energized.
When in the schedule should this walk happen?: Every quarter, scheduled for a loaded part of the day so the reading reflects real heat, not an idling unit.
Why do these items ask for a photo?: 10 of the 14 items call for photo evidence, 12 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 dry-type transformer quarterly inspection?: Louvers half-blocked by pallets or boxes stacked against the enclosure in a tight electrical room, so the winding runs hot all summer. A rising hum or buzz noted by the operator but never logged, so a loosening core clamp is only found after it rattles loose. Termination heat never scanned because the covers stay on, so a warm lug isn't caught until it discolors.
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.

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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 12 required photos exist. Approved walks roll into a branded turnover package with a tamper evident record behind every line.