1. Straight Line Rollers

   • Used in straight trench or duct runs.

   • Placed every 2–3 meters depending on cable weight.

2. Corner Rollers (90° or Variable Angle)

   • Used where the route bends.

   • Protects cable from sidewall pressure at corners.

   • Can be single corner units or multiple rollers forming a curve.

3. Manhole / Pit Entry Rollers

   • Guides the cable safely from drum into a trench, duct, or manhole.

   • Prevents sharp bending at entry points.

4. Triple / Quadrant Rollers

   • Special corner rollers with multiple wheels.

   • Used for large-diameter or heavy HV/EHV cables.

5. Suspension Rollers

   • Used for overhead pulls or when cables need to be supported above ground.

6. Lead-in / Bell-mouth Rollers

   • Installed at duct mouths to prevent sheath damage during entry.

• Roller groove width must be slightly larger than cable OD.

• Frame strength must support cable weight without bending.

• Heavier cables (HV/EHV) → larger, heavy-duty rollers with bearings.

• Straight runs → Straight line rollers.

• Bends → Corner rollers/quadrants (angle depends on route).

• Entry points → Bell-mouth or manhole rollers.

• Standard: every 2–3 m on straight runs.

• Closer (≤1.5 m) for large/heavy cables.

• Always place rollers before and after bends.

• Critical for bends.

• Formula:

  $P=RT$

  Where P = sidewall pressure (N/mm), T = pulling tension (N), R = bend radius (mm).

• Rollers must keep P < cable manufacturer’s limit (usually 500–1000 N/m).

• Underground ducts/trenches → Ground rollers (straight + corner).

• Overhead / substation projects → Suspension rollers.

• Marine / corrosive sites → Galvanized or stainless steel rollers.

1. Measure cable OD and weight/meter.

2. Map the pulling route (length, bends, entry points).

3. Calculate max pulling tension and check sidewall pressure at bends.

4. Select roller type:

   • Straight → standard rollers.

   • Bend → corner/quadrant.

   • Entry/exit → bell-mouth/manhole.

   • Overhead → suspension.

5. Place rollers with proper spacing and ensure stable ground/support.

Rule of Thumb:

• LV/MV short trench pulls → Straight + entry rollers.

• HV long trench pulls → Straight every 2 m + corner rollers + quadrant rollers.

• Extra-heavy/EHV cables → Larger rollers with ball bearings, closer spacing.

• OPGW/overhead cables → Suspension rollers.