Free checklist
Dry-type transformer annual maintenance checklist
The annual dry-type transformer service is the deep pass: the measurements, cleanings and tests a quarterly round doesn't reach. This checklist keeps the full service on record with the photos that make it defensible later. Work is commonly verified against NFPA 70B, NETA maintenance testing standards. Confirm the edition your authority having jurisdiction has adopted.
- Items
- 5
- Photos required
- 9
- Built for
- Subcontractors
Who runs it
The facility electrician recording the inspection during a planned outage, working the connections while the testing firm performs the electrical tests on the same unit.
When in the schedule
Once a year during a scheduled shutdown, coordinated with the NETA technician so the transformer is locked out, cleaned and torqued while it's cold, then tested before it's re-energized.
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.
Isolation and cleaning
- 2 photos
Transformer locked out and verified dead
Primary and secondary isolation confirmed, absence of voltage tested, lockout applied before any cover comes off.
- 2 photos
Windings and enclosure cleaned of dust and debris
Coils and cooling ducts vacuumed and wiped, dust and any tracking film removed from the coil faces and insulators rather than blown around.
Connections and coils
- 2 photos
Bolted connections checked to torque
Primary, secondary and tap connections checked with a torque wrench to the manufacturer's value, any that moved noted for re-scan next round.
- 1 photo
Coils, insulators and taps inspected
No cracked or chipped insulators, no discoloration or heat-glazing on the coils, tap links seated and matched to the intended setting.
Testing observed and recorded
- 2 photos
NETA electrical tests witnessed and logged
Insulation-resistance and any turns-ratio results from the testing tech recorded against the unit, out-of-range values flagged before re-energizing.
What usually sends this back
The failures are almost always the evidence, not the work
- Coils blown out with compressed air that just packs conductive dust deeper into the winding slots instead of vacuuming it out.
- Bolted connections re-tightened by feel with no torque wrench, so half are over-crushed and half never reached spec.
- The unit closed up and returned to service before the testing tech's insulation-resistance readings are back and recorded.
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 9 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 annual checklist cover?
- 5 items across 3 sections, covering isolation and cleaning, connections and coils, testing observed and recorded. 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 recording the inspection during a planned outage, working the connections while the testing firm performs the electrical tests on the same unit.
- When in the schedule should this walk happen?
- Once a year during a scheduled shutdown, coordinated with the NETA technician so the transformer is locked out, cleaned and torqued while it's cold, then tested before it's re-energized.
- Why does every item ask for a photo?
- 9 of the 5 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 annual inspection?
- Coils blown out with compressed air that just packs conductive dust deeper into the winding slots instead of vacuuming it out. Bolted connections re-tightened by feel with no torque wrench, so half are over-crushed and half never reached spec. The unit closed up and returned to service before the testing tech's insulation-resistance readings are back and recorded.
- 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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