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The Spare blocks are manufactured from Lycron. The unused space in the frame is filled with solid spare blocks. Using the spare blocks allows the option of fitting new cable in the future. Standard Spare blocks are divided up in seven sizes, 5, 10, 15, 20, 30, 40 and 60 mm in square.
Spare Block

Technical specifications

Surplus room in each frame is filled out with solid insert blocks. Called spares, they bear the designation A/0. Blocks are referred to by their width (A), followed by the designation /0 (indicating solid). Thus a block with a width and height of 15 mm (0.59”) is referred to as 15/0. The length of insert blocks is always 60 mm (2.36”)

Spareblock Sizes
Block Weights


GR/DWC-34/01/SEP 2007 & RDSO/SPN/204/2011

Train EN-45545
HL 1, HL 2, HL 3


Trade name: 
MCT Brattberg SpareBlock


Lycron data

Read Lycron data sheet:
Data sheet Lycron

Lycron is halogen free and flame retardant.


For all approvals, please also see Certificates 


Correct and safe installations

To achieve the highest standard of safety, a cable or pipe transit must be installed correctly. As there are many different types of frame – which may be either welded, bolted or glued into position – and insert block, it is essential that installers known when to use the most appropriate installation method.

For more information, please view following instructions, videos or download manuals as PDFs.

RGS frame, horizontal installation
RGS frame, vertical installation

Download pdf instructions 

Other insert blocks

Standard Block

Standard Block for a fast and safe installation.

See more


Newly developed Insert Block that provides greater flexibility, simple and safe installation.

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Eleven blocks and 66 dimensions.

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The U-Block is used to convert the external dimensions of Insert Blocks, AddBlocks and Spare Blocks to the next modular size.

See more


Insert blocks for Waveguides

See more