Heathrow Airport, FEGP and Substation Earthing

• Prepared airside RAMS for a two man crew, both holding City and Guilds level confined space training, with buried services training, Heathrow confined space licensing and permit to excavate from the main contractor written into the method.
• For the FEGP pits, aired each pit for ten minutes and lowered a gas monitor to several depths before entry, kept a top man on constant watch with the entrant connected to a winch and escape set, and barriered the open pit throughout.
• Drove copper bonded rods in 1.2 m sections to an initial depth of 12 m using a 110 V percussion hammer and a driving head, coupling each section and repeating until the design depth or the target resistance was reached. Percussion work was swapped every 25 minutes and capped at 1.5 hours per operative per day.
• Tested each earth with a calibrated digital earth tester to prove the one ohm value before handover, at about one day per earth on the FEGP stands and two days for the substation.
• Cleared the work area of all debris during the shift for FOD control and stopped work in any electrical storm.

One ohm earths installed and tested to BS 7430:2011 for the FEGP stands in 2017 and for UKPN Substation 128 in 2018, in a confined space, airside environment. This work is the basis of the airfield and substation earthing service Fabier offers today.