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.
- Items
- 6
- Photos required
- 8
- Built for
- Subcontractors
Who runs it
The facility electrician on the quarterly electrical round, working entirely outside the enclosure with the unit energized.
When in the schedule
Every quarter, scheduled for a loaded part of the day so the reading reflects real heat, not an idling unit.
The checklist
Every item, and the photo that proves it
The photo count on each row is what RTI would require before the item can be submitted. Copy the list as is, or load it into RTI and let the gate enforce it.
Cooling and temperature
- 2 photos
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.
- 1 photo
Enclosure and winding temperature within normal range
Any built-in winding temperature indicator read and compared to the last round, enclosure skin not hot to a back-of-hand check for the load it's carrying.
Sound and load
- 1 photo
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.
- 1 photo
Load current read at the secondary
Phase currents clamped at the secondary and compared against nameplate rating, no single phase running far above the others.
Terminations and grounding
- 2 photos
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.
- 1 photo
Ground and bonding connection intact
Enclosure ground and the equipment grounding conductor landed tight and unbroken, no corrosion or paint under the lug.
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.
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 8 required photos exist. Approved walks roll into a branded turnover package with a tamper-evident record behind every line.
Submission state
The gate is enforced on the server, so it holds even if the phone is offline when the walk happens.
Verified against
Common questions
- What does this dry-type transformer quarterly checklist cover?
- 6 items across 3 sections, covering cooling and temperature, sound and load, terminations and grounding. 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 does every item ask for a photo?
- 8 of the 6 items call for photo evidence. 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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