The Technical File | Groundforce Groundforce Shorco | Technical File Issue 3.0 Single Acting Manhole Brace The Single Acting Manhole Brace range consists of a series of non-modular, (single piece) hydraulically adjustable legs which are connected together to support square or rectangular excavation sizes ranging from 1.15m to 3.0m. The range consists of 5 individual legs, each incorporating a single acting hydraulic ram unit that provides on-site length adjustment in each leg. Note: these legs are relatively light duty in terms of load capacity and the single acting hydraulics necessitate manual retraction after pressure release. Features / benefits Relatively lightweight - can be used with small excavators. Simple and quick to assemble on site. Ideal for light to medium duty applications in 4-sided excavations. Single acting hydraulics requires only a single hose connection. Hydraulic isolation valve is available on some models to prevent fluid loss on de-pressurisation. 540 Legs, being constructed from high strength aluminium alloy, weigh only 35kg making them ideal for use with utility companies. Compatibility Legs A and B are interchangeable with each other. Legs 400S and 400M are interchangeable with each other. 540 Legs are non-interchangeable with other leg types. 1.3.1