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Wires and cables in industrial building

Short answer

For power: PVC/XLPE armoured cables (1.1kV) for feeders and motors, unarmoured for panels, flexible cables for portable equipment, and bus ducts for high currents. For lighting: PVC single-core copper wires in conduit (1-6mm²), FR/FRLS/LSZH for fire safety. Special types include fire-survival, heat-resistant, control, and instrumentation cables. Selection based on current rating, voltage drop, installation method, and fire performance.

Describe the various types of wires or cables usually used in industrial building for power and lighting system.

Wires and cables are classified by conductor, insulation, construction and use. The common types in industrial buildings are:

For power distribution

  1. PVC insulated armoured cables (1.1 kV), Cu or Al, IS 1554: 3.5 core or 4 core cables from the main panel to sub-panels and motors, laid on trays, in trenches or buried. Steel armour gives mechanical protection.
  2. XLPE insulated armoured cables, IS 7098: rated 90 °C, so they carry more current than PVC; used for large feeders and HV (11 kV, 33 kV) incoming cables.
  3. Unarmoured PVC/XLPE cables: for runs inside panels, conduits and protected cable trays.
  4. Flexible cables (multi-strand, rubber or PVC sheathed): for portable tools, cranes, hoists, welding sets and moving machines.
  5. Bus ducts / bus trunking: for very high currents (from transformer to main panel), as an alternative to many parallel cables.

For lighting and small power

  1. PVC insulated single-core copper wires (IS 694), 1.0–6 mm²: run in PVC or metal conduit for lighting, fans and socket circuits. Colours: red/yellow/blue (phase), black (neutral), green (earth).
  2. FR / FRLS (fire-retardant, low-smoke) wires: where fire safety matters.
  3. LSZH (low smoke zero halogen) cables: for crowded or enclosed areas; give little smoke and no toxic gas in a fire.

Special-purpose cables

  1. Fire-survival cables: keep working during a fire; for fire alarm, emergency lighting and fire pumps.
  2. Heat-resistant cables (silicone, PTFE insulation): near furnaces and ovens.
  3. Control cables (multi-core, small size, screened): for control circuits, interlocks and PLC wiring.
  4. Instrumentation and data cables (twisted, screened): for sensors and communication, to reduce noise.
  5. Bare or PVC-covered earth conductors (GI strip, copper): for earthing.

Selection points

Current rating with derating, voltage drop, short-circuit withstand, installation method, mechanical protection, fire performance and cost.

✓ Answer checked by Claude Opus 5.5 (high effort)

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