TM 55-1930-209-14&P-19 Table 9-3.  Preventive Maintenance Checks and Services for Electrical Power Systems(Continued) B - Before D - Daily Q -  Quarterly D - During W - Weekly S -  Semiannually A - After M - Monthly A -  Annually INTERVAL ITEM PROCEDURES EQUIPMENT ITEM TO BE CHECK FOR AND HAVE IS NOT READY/ NO. INSPECTED REPAIRED OR ADJUSTED AVAILABLE IF B   D   A   D  W  M   Q   S   A AS NECESSARY · 4) Clean circuit breakers, contacts and relays with fine sandpaper to remove black discoloration.  Do NOT use emery cloth. · 5) Clean arc chutes on circuit breakers with a fine file.  Vacuum to remove residue. EMERGENCY WARNING ELECTRICAL POWER SYSTEM Fumes from battery electrolyte may be flammable    and    explosive.        DO    NOT smoke    or    have    open    flames    when checking  electrolyte,  or  when  working on   battery   bank.   Avoid   contact   with eyes   and   skin.      Wear   safety   glasses, gloves, and rubber aprons when handling    electrolyte.        Electrolyte    is highly toxic to skin, eyes and respiratory     system     and     can     cause severe burns. 1 ·     · · Batteries a. Check batteries in bank for proper elec- Electrolyte level trolyte level.  Add distilled water or clean low. water to bring level above plates. · b. Check that battery bank is secure and that electrical cable fittings are tight and coated with anti-corrosion grease. Cor- rect as necessary. · c. Check for damage and loose fittings, Fittings, wires wires and fasteners. Replace or tighten and/or fasteners as necessary. damaged or loose. · d. Wipe all battery components clean. e. Replace defective status lamps. f. Check electrolyte level daily and make sure it covers plates in each cell of all batteries. g. Visually check for loose or damaged Cables loose or cabling. Make sure cabling is firmly damaged. attached, free of corrosion, and not sub- ject to rubbing or chafing. · h. Check for loose or damaged electrical Electrical connec- -connections, switches, wiring, mounting tions, switches, systems, hangers, and insulating mate- wiring, and mount- rial. Repair, replace, or tighten as neces- ing systems loose sary using insulated tools. or damaged. 9-6