Energy distribution boxes, tunnel lighting
FULLY CUSTOMISABLE
The Tunnel Distribution & Lighting Box provides tunnel contractors with a complete solution for temporary electrical installation that complies with competent local authorities.
WE-POWER developed the TDLB to withstand harsh conditions in accordance with BS6164, which provides useful guidance on voltages, equipment enclosures, cabling, electrical protection and lighting systems to be used in tunnels.
Dust, water and concrete casting levels require heavy-duty steel casings and high-quality components mounted inside electrical equipment, such as circuit breakers, transformers and switches, to ensure high performance and continuity of service that meets health and safety regulations in order to protect operators.
USE: Temporary electrical installation in compliance with local standards
INSTALLATION ENVIRONMENT: Tunnels, construction sites, harsh environments
TYPICAL TUNNEL DISTRIBUTION SCHEME – 3300V
For longer tunnels, it may be necessary to step up the voltage at the entrance to 3300 V and step it down to 400 V / 230 V and 110 V at regular intervals. Stepping up to 3300 V requires the use of special cables and connectors, however, the distances that can be fed from a single source are significant (lots of kilometres). The standard practice is to install 3300 V “Half Couplers” on transformers that can be electrically interlocked. This “plug and socket” mechanism enables the installation to be quickly expanded as the tunnelling advances.
Due to the size of the 3300V switchgear, circuit protection is provided at the source, but the power supply for each transformer is individually protected by fuses. The 3300 V transformers can incorporate a single-phase 110 V output to power tunnel lights and small power supplies. Alternatively, dual output transformers can be used to supply 400 V power for bigger machinery, as well as 110 V for tunnel lights and small power supplies.
Reduced LV limits defined in BS7671 but higher at 55 V than those preferred in BS6164. However, all outlets are protected by 30 mA RCDs, which provide additional basic protection.
The additional shock risk associated with this arrangement is minimal.