We provide periodic inspection, testing and maintenance of the following electrical services: 

Lightning Protection Systems (LPS)

The purpose of this inspection is to ensure that the LPS conform to the design standard in all respects.

The inspection includes checking technical documentation, visual inspections, testing and logging in an inspection report.

Frequency of Testing:
The lightning protection system shall be tested electrically every 12 months [¹].

Furthermore it is considered beneficial to conduct earth resistance testing over different times of the year to get an indication of seasonal variations. An 11 month cycle is typically set so not to exceed the 12 month period and to monitor the affect it has on the electrode value(s).

Lightning protection systems utilised in applications involving structures with a risk caused by explosive materials should be visually inspected every 6 months [²]. Again in this case electrical testing of the installation should be performed once a year, and typically at an 11 month cycle.

Inspection and Testing Procedure:
Visual inspections should be made to ascertain that:
-the design conforms to this standard,
– the LPS is in good condition,
– there are no loose connections and no accidental breaks in the LPS conductors and joints,
– no part of the system has been weakened by corrosion, especially at ground level,
– all visible earth connections are intact (functionally operational),
– all visible conductors and system components are fastened to the mounting surfaces and components which provide mechanical protection are intact (functionally operational) and in the right place,
– there have not been any additions or alterations to the protected structure which would
require additional protection.
Testing should include:
– performing continuity tests, especially continuity of those parts of the LPS which were not
visible for inspection during the initial installation and are not subsequently available for visual inspection;

[¹]BSEN 62305-3 D.6.5
[²]BSEN 62305-3 E.7.1

Surge Protection Measures (SPM) Systems

Lightning Surge Protection Devices (and their means of isolation, if provided) shall be inspected in accordance with manufacturer’s instruction at intervals not exceeding 12 months [¹] or whenever electrical testing of the LPS is performed (typically on an 11 month cycle). SPDs shall also be inspected after any suspected lightning strike to the structure.

[¹]BSEN 62305-3 D.6.7

Power Earthing Systems (HV/LV)

Substation Power Earthing Systems should be inspected, maintained and repaired so as to ensure they will operate in the manner required on an ongoing basis.

Frequency of Testing:

The frequency of inspection and testing should be set according to EPR, risk of theft, damage,
and deterioration.

A 5 year [¹] cycle is typically chosen for infrequent detailed physical examination (testing) and inspection.
A frequent visual inspection is typically carried out on a 1 year [¹] cycle.
If an extraordinary event occurs (e.g. delayed fault clearance), additional ad-hoc inspection
and testing may be required.

[¹]BS 7430 Section 10.4

Testing Procedure:

As part of the maintenance testing is carried out, the tests should include:

– resistance tests across joints using the micro-ohmmeter;

– checking the integrity of the bonding of all normally accessible metalwork (such as the tank of a transformer) to the substation earth or grid;

– measurement of the substation earth value (to be compared with the design specification). Once a new substation earth resistance is obtained, it should be used to recalculate the substation EPR using up-to-date earth fault current data and earth fault current return paths(earth wires/cable sheaths etc.). Safety voltages and conductor current ratings should be recalculated and any deficiencies identified.

– for substations with segregated earthing, checking the integrity of the segregation.

Defects should be listed and prioritised for remedial action.