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GuideSizes chart

RCC manhole cover sizes chart

Use this guide to compare frame size, clear opening, and typical use cases for common RCC manhole cover sizes. Buyers often ask only for the top cover size, but correct selection depends on the full frame-and-opening relationship.

Understand the three main dimensions

Cover size

The visible top cover dimension that sits on the frame.

Frame size

The outer footprint of the full frame assembly placed over the chamber.

Clear opening

The usable inside opening for access, maintenance, and inspection.

Common sizeTypical opening needTypical use caseProduct link
300 x 300 x 50 mmSmall access openingsCompact service chambers and light utility pointsView size
460 x 460 x 75 mmSmall to medium utility openingsDrainage and utility chambers with moderate access needsView size
500 x 500 x 100 mmMedium chamber accessResidential and commercial inspection pointsView size
600 x 600 x 100 mmLarge access openingMunicipal, utility, and maintenance chambersView size
850 x 850 x 150 mmHeavy-duty chamber accessHigher load or larger opening requirementsView size

How to shortlist the right size

  1. Measure the existing chamber opening or required access opening.
  2. Confirm whether the chamber needs a square, rectangular, or round format.
  3. Check the traffic condition and match the load requirement.
  4. Confirm the frame footprint can sit properly on the chamber top.
  5. Review the exact variant page before ordering bulk quantity.

Common sizing mistakes

  • • Ordering by visible cover size without checking clear opening.
  • • Matching chamber width but ignoring frame seating area.
  • • Choosing a size first and checking load class later.
  • • Ignoring maintenance access requirements for workers and tools.