In short
Keep critical spares on the shelf before you need them: the cable sizes, breakers, contactors, bearings, seals, gaskets and fasteners used on your most important machines. A short, well-chosen store list prevents most avoidable downtime.
Key facts
- Build the store list from your critical machines, not from a generic catalogue.
- MCBs protect small circuits; MCCBs handle higher currents with adjustable trips; RCCBs detect earth leakage but do not protect against overload.
- XLPE-insulated cable runs hotter than PVC cable, so it carries more current for the same size.
- Grade 8.8 and 10.9 bolts are high-tensile; never replace them with ordinary mild-steel bolts on flanges or rotating equipment.
- Gasket material (CAF, graphite, PTFE, spiral wound) must match the fluid, temperature and pressure.
Most plant stoppages are not caused by a major failure. They are caused by a small part nobody had in stock — a contactor, a bearing, a gasket, a length of cable. A maintenance store that holds the right consumables turns an eight-hour wait into a thirty-minute repair.
Start from your critical equipment
Walk through the plant and list the machines that stop production when they fail — main pumps, compressors, boilers, chillers, conveyors, cooling-tower fans. For each one, record the bearing numbers, seal sizes, belt sizes, motor starter components and gasket dimensions. That list, not a generic catalogue, is your minimum stock.
Electrical consumables
Cable
Power and control cable is specified by conductor, insulation, number of cores and cross-section (mm²).
| Insulation | Max conductor temperature (typical) | Notes |
|---|---|---|
| PVC | 70 °C | Economical, general purpose |
| XLPE | 90 °C | Higher current for the same size, better in hot plant areas |
Armoured cable is used where it is buried or at risk of mechanical damage. Cable size must be chosen by a qualified electrician from the load current, run length (voltage drop), installation method and ambient temperature — Pakistan's summer heat reduces current-carrying capacity, especially in cable trays near hot equipment.
Switchgear and protection
Switchgear and protection devices are worth stocking in the ratings your panels actually use:
- MCB (miniature circuit breaker) — overload and short-circuit protection for lighting and small power circuits.
- MCCB (moulded case circuit breaker) — higher currents, often with adjustable trip settings, for motor feeders and distribution.
- RCCB / RCD — trips on earth-leakage current to protect people. It does not protect against overload, so it is used together with an MCB or MCCB.
- Contactors and overload relays — the parts in a motor starter that wear out most often.
Also keep cable glands, lugs, industrial IP55/IP65 sockets and LED fittings in the sizes you use.
Mechanical consumables
Bearings, seals and packing
Bearings are the classic critical spare. Record the full bearing number (it encodes type, bore and clearance) and keep at least one set for each critical pump and motor. Stock bearings, mechanical seals, oil seals, O-rings and gland packing to match.
Fasteners
High-tensile fasteners are graded by strength:
| Grade | Tensile strength (approx.) | Typical use |
|---|---|---|
| 8.8 | 800 MPa | General high-tensile bolting, flanges, machinery |
| 10.9 | 1000 MPa | Heavily loaded joints, couplings |
| SS 304 / 316 (A2 / A4) | Lower than 8.8 | Corrosive environments |
Never replace a high-tensile bolt with an unmarked mild-steel bolt on a pressure flange or a rotating machine.
Gaskets
| Gasket material | Suitable for |
|---|---|
| CAF (compressed asbestos-free fibre) | Water, low-pressure steam, oils, general service |
| Graphite | Higher temperatures, steam, thermal oil |
| PTFE | Aggressive chemicals, food-grade service |
| Spiral wound | High pressure and temperature, cyclic service |
Gaskets can be cut to your flange drilling from sheet, so keeping a few sheets of the right material is often more useful than a box of ready-cut sizes.
Keep the store working
- Label shelves with the machine each spare belongs to.
- Set a minimum quantity and reorder when stock reaches it.
- Store bearings flat in their original packing, and rubber seals away from heat and sunlight.
Need a part matched?
Tell us the size or send a sample and we will match it. You can view the consumables range or send us your store list for a quotation.
Frequently asked questions
What is the difference between an MCB, an MCCB and an RCCB?
An MCB protects small circuits against overload and short circuit. An MCCB does the same for higher currents and often has adjustable trip settings. An RCCB detects earth-leakage current to protect people from shock but does not protect against overload, so it is used together with an MCB or MCCB.
Is XLPE cable better than PVC cable?
XLPE insulation tolerates a higher conductor temperature (typically 90 °C versus 70 °C for PVC), so an XLPE cable can carry more current than a PVC cable of the same size and copes better in hot areas. PVC cable is more economical for general wiring.
Which gasket material should I use for steam?
For low-pressure steam, CAF gaskets are commonly used; for higher temperatures graphite gaskets are preferred, and spiral-wound gaskets are used for high-pressure or cyclic service. Always check the gasket's temperature and pressure rating against the line conditions.
Which spare parts should a factory maintenance store keep?
Stock the parts that would stop critical machines: bearings, mechanical seals and gland packing for main pumps and motors, contactors and overload relays for starters, the breaker ratings used in your panels, belts, gaskets for common flange sizes and high-tensile fasteners.
