RoLE System Update

NR/L3/ELP/29987 Module 4 - Maintaining the Integrity and Safe Operation of 25 kV A.C. Electrified Lines

4.4 ‘Green’ Bonds

Connections between the main earthing terminal (MET) of an LV network and the traction return circuit are designated as 'green bonds'.

If disconnected, the LV equipment or LV circuit might no longer be earthed.

As a consequence: a fault on the LV system, or a broken overhead contact line coming into contact with the LV equipment, might not be detected.

Green bonds shall only be disconnected by competent staff and shall work to a method of work authorised as in table 1.

Where the DPE is not competent in assessment of electrical risks, they shall follow the advice of an identified competent engineer

Maintenance Delivery Unit Electrification and Plant Maintenance Engineer
Projects Designated Project Engineer

Table 1 – Authorisers of methods of work

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