Station DC System and Charger Inspection

Inspection template for verifying substation DC supply integrity, charger output, float voltage, and unintentional grounds supporting protective relays and breakers.

Inspection Details and Safety Controls

• Inspection scope and equipment ID documented
  Record the station name, DC system identifier, charger/battery bank ID, and inspection date.
• Work authorization and switching/clearance status verified
  Confirm the inspection is authorized and any required clearance, permit, or access control is in place.
• LOTO and electrical PPE requirements confirmed
  Verify lockout-tagout, shock protection, arc-flash boundaries, and PPE requirements per OSHA 1910.147 and NFPA 70E before exposure to energized DC equipment.
• Test instruments verified and suitable for DC measurements
  Confirm meter calibration status, leads condition, and correct DC voltage range before use.
• Visible hazards or access obstructions present
  Identify any trip hazards, blocked access, missing barriers, exposed conductors, or other unsafe conditions.

Battery Bank and DC Supply Condition

• Battery bank enclosure and rack condition acceptable
  Check for corrosion, leakage, swelling, cracked cases, damaged racks, or missing covers.
• Battery terminals and intercell connections secure and clean
  Inspect for loose hardware, corrosion, overheating, discoloration, or evidence of high resistance connections.
• Battery electrolyte level within acceptable range
  For flooded cells, verify electrolyte level is within manufacturer limits and no cell shows abnormal loss.
• Battery room ventilation and housekeeping acceptable
  Confirm ventilation is operating as intended, vents are unobstructed, and the area is clean and dry.
• DC distribution fuses, breakers, and labels intact
  Verify protective devices are properly labeled, not bypassed, and show no signs of overheating or damage.

Charger Output and Float Voltage Verification

• Charger DC output voltage recorded
  Measure the charger output at the designated test point and record the value.
• Measured charger output within manufacturer or site acceptable range
  Confirm the charger output is within the documented operating range for the station DC system.
• Battery float voltage recorded
  Measure float voltage at the battery bank or specified test point and record the value.
• Float voltage within manufacturer or site acceptable range
  Confirm float voltage is within the documented acceptable range and stable during observation.
• Charger alarms or abnormal indications present
  Check for AC fail, DC fail, ground alarm, overtemperature, overload, or other abnormal charger indications.

Ground Detection and Insulation Concerns

• Ground detector indicates no unintentional ground
  Verify the DC ground detection system shows normal status and no active ground alarm is present.
• Positive and negative pole-to-ground readings recorded
  Record measured pole-to-ground voltage readings for both DC poles at the designated test point.
• Pole-to-ground readings consistent with expected system balance
  Confirm the measured pole-to-ground values do not indicate an unintentional ground or abnormal imbalance.
• Insulation, wiring, and terminal blocks show no damage or contamination
  Inspect for cracked insulation, wet contamination, carbon tracking, loose conductors, or damaged terminal blocks.

Protective Relays and Breaker Control Power

• Protective relay DC supply status normal
  Confirm relay DC supply indicators show normal operation and no undervoltage or loss-of-control-power condition.
• Breaker control power available at designated test point
  Verify breaker trip/close control power is present and stable at the designated point of verification.
• Any abnormal relay, breaker, or DC control indications observed
  Document any alarms, failed indicators, nuisance trips, or abnormal control power behavior.