Substation Inspection Checklist (Routine Visual Inspection)
A general visual and routine inspection of an outdoor or indoor substation, done by looking from a safe position. It does not ask anyone to open, switch or work on live equipment. It records what the inspector saw, so a defect becomes an action with an owner before it becomes an outage or an incident.
On the routine visit set by your maintenance plan, and after a fault or a storm · 46 checks · free printable PDF
Legal basis checked 26 October 2026
What the checklist covers
Perimeter, access control and signage
- Perimeter fence and gates intact, gates locked, no gaps under the fence
- Danger and "authorised persons only" signs in place and legible
- Access log or key register up to date; no unauthorised entry recorded
- No vegetation growing into the yard or near conductors
- No signs of intrusion, theft of copper or earthing, or animal nests
Housekeeping
- Yard surface stone in place and drainage clear
- No combustible material, waste or stored items in the substation
- Roof, doors and cable trenches free of water ingress and vermin
Switch-room and transformer premises (Electrical Machinery Regulations, regulation 6)
- Clear working space kept for operating and maintenance staff
- Ventilation working; equipment at a safe temperature
- Rodent, leak, seepage and flood proofing intact
- Lighting good enough to read every instrument, label and notice
- Doors and gates open outwards and open easily from inside
- Fire extinguishers suitable for electrical equipment, in place and in good order
- No way to reach in and touch bare conductors or exposed live parts
- Entry limited to authorised persons, or people under their control
Transformers
- Oil level gauge within the marked range
- No oil leaks on the tank, radiators, valves or the ground beneath
- Oil and winding temperature readings within the normal range, where the instruments are fitted; maximum pointers recorded
- Silica gel breather colour normal (not saturated)
- Bushings clean, with no visible cracks, chips or tracking marks
- Buchholz relay and pressure relief device show no operation (where fitted)
- Bund walls intact and free of oil and water
- Cooling fans and pumps running when required (where fitted)
Switchgear, insulators and cables
- Switchgear position indicators match the expected switching state
- Protection relay panels show no alarms or trip flags
- Gas pressure or density gauges in range on SF6 equipment (where fitted)
- Insulators and surge arresters free of visible cracks and contamination
- Cable terminations show no visible sign of overheating or discolouration
- No unusual noise, smell of burning or ozone, or visible discharge
- Panel doors closed and locked; interlocks and padlocks in place
Earthing (visible connections)
- Visible earth conductors and connections present, intact and not cut or removed
- Earth connections on fences, gates and equipment frames in place
Batteries and chargers
- Battery charger healthy, with no alarm
- Battery bank clean, with no visible corrosion, swelling or leaks
- Battery room ventilation clear
- Auxiliary supply, lighting and emergency lighting working
Fire equipment and safety equipment
- Fire extinguishers present, sealed and within their service date
- Rubber mats, insulating gloves and operating sticks present and within their test date
- Single-line diagram and emergency contacts displayed
Records
- Readings recorded for trending: oil level, temperatures and maximum pointers, gas pressures, counters (where fitted)
- Defects from the last inspection closed, or still open with an owner and a due date
- Any switching, access or work since the last visit is recorded in the site register
- Next inspection date set
Outcome
- Substation in normal condition
- Any defect reported to the responsible person and logged with an owner and a due date
How to use this checklist
- 1Only an authorised person enters the substation, following the site's access rules.
- 2Inspect from a safe position. Do not open live compartments, switch or touch equipment.
- 3Work through the perimeter, housekeeping, transformers, switchgear, earthing, batteries and fire equipment in order.
- 4Mark every item OK, Defect or N/A, and note readings such as oil level, temperature and battery charger status where gauges are fitted.
- 5Record each defect with its location, report it under your site's procedure, and give it an owner and a due date.
A general guide. Follow your site's own standards and the manufacturer's instructions. Visual checks from a safe position only: opening live compartments, switching, and entering or working on live equipment are for authorised persons under the site's own rules. In South Africa the Occupational Health and Safety Act 85 of 1993 and its Electrical Installation Regulations and Electrical Machinery Regulations apply; on a mine, the Mine Health and Safety Act 29 of 1996 and its regulations apply. Regulation 6 of the Electrical Machinery Regulations, 2011 sets the conditions for enclosed premises housing switchgear and transformers: clear working space, ventilation, proofing against rodents and flooding, lighting, outward-opening doors, suitable fire extinguishers (at unattended premises, while work is in progress), no reach to live parts, and entry by authorised persons only.
Legal basis checked on against: Electrical Machinery Regulations, 2011 (GN R250 of 25 March 2011), regulation 6.
Convert this checklist into a digital form
Run it on an Android phone with no signal, attach photos as evidence, and every failed item raises an issue with an owner and a due date.
Start the trial from here and this checklist is waiting in your workspace as a ready-made form.
Paper finds the defect. Then what?
On paper, a ticked "Defect" box often stays a ticked box. In Inspecable the same checklist keeps going after it is signed:
- Run the checklist on an Android phone with no signal; it syncs when the crew is back in range.
- A failed item raises an issue with an owner and a due date.
- A corrective action cannot close without evidence and a signature.
- Every completed inspection produces a signed PDF with its photos.
Questions
How often should a substation be inspected?
On the routine interval in your maintenance plan, which is often monthly for a visual inspection, plus after a fault, a storm or a break-in. Critical substations may be checked weekly. Thermal scans and oil tests run on their own schedules.
Who may carry out a substation inspection?
A person authorised under the site's electrical rules to enter the substation. The visual checks on this form do not involve operating or working on equipment; anything beyond looking is for authorised persons under the site's own procedures.
What are the most common defects found?
Damaged fencing or locks, missing danger signs, oil leaks on transformers, discoloured silica gel in breathers, rodent or bird entry, corroded or loose earth connections, and battery or charger alarms. Most are cheap to fix if caught early.
Can this checklist be used on a mine?
Yes, as a visual inspection guide. On a mine the Mine Health and Safety Act and its regulations apply, and the mine's own electrical standards set who may enter and what must be checked. Add those requirements to the form.
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