Manhole Boxes

Manhole boxes are similar to trench boxes in their basic function, however they incorporate integral end return panels thus providing additional ground support, making them ideal for installing pre-cast manhole rings in trench runs as an alternative to using sheets and frames. There are five basic sizes of Manhole Box available to cater for common sizes of pre-cast manhole rings. Each box can be assembled and installed quickly and without the need for an operative to enter the unsupported excavation. Manhole Boxes can be used in most ground conditions to support trenches with depths of up to 5.5m by utilising the base module with two box tops and a variety of different strut types.

  • Can be used in trenches up to 5.5m deep in conjunction with up to two top extenstion units
  • Five panel lenghts are available to suit all common pre-cast ring sizes.
  • Manhole boxes may be installed in either a pre-dug trench in stable ground, or by a progressive 'dig and push' method.
  • Handrail panels are available for this product.
  • Four-way handling points to aid safe assembly.


Specification Manhole Box Type Reference (plate length)
  2.5m Box 3.0m Box 3.5m Box 4.0m Box 5.0m Box
Plate Height (m) 2.5 (base) 1.5 (top) 2.5 (base) 1.5 (top)
Square Box Assembly Weight (kg)* 2426 (base) 1668 (top) 2702 (base) 1846 (top) 3020 (base) 2044 (top) 3269 (base) 2208 (top) 5038 (base) 3394 (top
Plate Thickness (mm) 107 127
Weight of individual Plates (kg) 1045 (base) 745 (top) 1163 (base) 824 (top) 1282 (base) 903 (top) 1400 (base) 982 (top) 2075 (base) 1475 (top)
Manhole Ring Diameter (mm) 1050, 1200, 1350 1350, 1500, 1800 1800, 2100 2100, 2400, 2700 2700, 3000, 3660
Maximum Trench Depth (m)** 5.5 5.5
Internal width (m) 1.31 - 5.11 (strut length + 900mm) 2.794 - 6.394
External width (m) 1.53 - 5.33 (strut length + 1120mm) 3.047 - 6.647
Clearance below strut (m) 1.5 1.4

* Typical - weights will vary with trench width

** Maximum depth is based on one base and two top extensions being connected together

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