Airbus Stevenage, ITC

• Wrote the integrated test and commissioning procedure to BS EN 62305-3 Section 7, covering prerequisites, design parameters, pre start checks, test procedures, interface, documentation, demonstration, instrumentation, staffing and permits.
• Inspected the whole system: a 25 x 3 mm bare aluminium air termination network with all roof plant, flues and ducts cross bonded; 25 x 3 mm PVC sheathed down conductors connected to the steel frame at high and low level; and a bare 25 x 3 mm copper earth termination network terminating on earth bars in inspection housings, with external joints silver brazed and Denso wrapped.
• Tested every earth by the fall of potential method in soft ground: earth isolated at the earth bar, current probe at about 50 m and potential probe at about 30 m, driven no more than 200 mm, with the potential probe moved 5 m each way and the three readings averaged. Where the ground was hard we used the dead or known earth method against an independent electrode.
• Continuity tested every conductor that could not be seen, with leads connected at low and high level, and calculated the combined resistance of the earth ring against the 10 ohm maximum in BS EN 62305-3.
• Pre witnessed the results before offering the system for formal witnessing, then completed the test sheets and certificate for the O&M manual and upload to the project document system.

The system was inspected, tested and certificated with all earth readings recorded against the site plan and a combined resistance below 10 ohms.