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MaterialsUpdated 18 Sept 2026

Which enclosures can be used in precast and cast-in-place concrete?

Short answer

For electrical installations in pre-cast and cast-in-place concrete, we recommend our IBT range, which has been developed specifically for these applications and tried and tested over many construction projects. Available in different sizes and shapes, IBT enclosures have a robust, highly stable design that performs when the concrete is both wet and dry. The technology prevents the enclosure being crushed under the weight of the concrete, a patented diaphragm sealing system prevents displacement or infiltration as concrete is poured, and a patented support spar mounts the box to vertical or horizontal formwork.

Our IBT range is ideal for electrical installations in pre-cast and cast-in-place concrete, as it has been specifically developed for such applications and tried and tested over many construction projects. The IBT solutions, available in different sizes and shapes, offer a robust and highly stable design that ensures optimal performance both when concrete is wet and when it is dry.

Many buildings require the encasing of electrical wires and enclosures in concrete slabs, as this can lead to shorter construction times while also fast-tracking electrical installation and wiring activities. Reliability of the equipment and positional stability are the two major aspects that should be ensured in such projects.

Our concrete construction pages explain the functionality and features of the IBT range: https://www.spelsberg.co.uk/solutions/concrete-construction/overview/ The full IBT portfolio of housings for pre-cast concrete applications is at https://www.spelsberg.co.uk/solutions/concrete-construction/products/ibt-system/

Our technology prevents crushing of the enclosure under the weight of the concrete, as well as any stressing or failure as the building settles over time. The IBT products also use a patented diaphragm sealing system to prevent displacement or infiltration within the structure when concrete is being poured. Mounting is carried out with a highly secure, patented support spar, which can be used with both vertical and horizontal formwork, supporting quick and easy installation.

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