Earth electrodes and lighting columns

This Q & A is one of the thousands posted in our Technical Expertise area and answered by our Voltimum Experts.

Question:

Lighting columns are sometimes installed in a pre-installed plastic sleeves. Some DNOs have asked for earth electrodes to be installed on these columns using this installation method as they say they are insulated from the general mass of earth.

Others have root protection consisting of a thermoplastic coating or thermoplastic adhesive tape. Most standard columns have, as a minimum, bitumen-based root protection.

What is the opinion of an expert on the necessity of installing earth electrodes on lighting columns installed in plastic sheaths and also the need for earth electrodes with root protection as indicated above?

Answer:

Gary Parker, ECA

I would have thought the column would be classed as an exposed conductive part, there would be no need to have an electrode with these if they are adequately connected to the earthing system.

If the DNO are requesting this as part of an EV future proof element, as a supplement to their earthing or as a precaution against lost neutrals, that is their choice. I don't see any reason from a BS 7671 point of view to have a separate electrode.  Providing all the column is adequately connected, it should be fine.