Read earthing measurements together with test conditions and method. One resistance value is not proof of overall installation conformity.
What is an earthing measurement?
An earthing measurement evaluates electrical properties of a defined earthing arrangement using a specified method. The measured quantity and method depend on system type, test purpose and applicable criteria.
So the phrase 'earthing was measured' does not explain test scope. The report should identify which electrode or circuit was tested and why.
What belongs in an earthing report?
The report should identify the facility, earthing scope, test points, instrument and applicable calibration data, method, relevant ground/weather conditions, results and assessment criteria.
The Ministry's current notice says the installation design is required for electrical, earthing and lightning protection inspections. Differences between design and site should be visible in findings.
How should a result be interpreted?
A reading cannot be generalized without considering system arrangement, test location, parallel paths, season and ground conditions, instrument and method. Different tests may answer different questions.
There is no single pass resistance value that applies to every facility. Select and state acceptance criteria according to the protection design and applicable test standard.
Preparation and follow-up
Share current electrical/earthing drawings, prior reports, recent alterations, test access points and safety arrangements in advance. Energized or de-energized conditions may affect method and scope.
If results are adverse, simply repeating the test is not a remedy. Inspect connections, conductors, electrodes and protection design, then recheck after corrective work using a suitable method.
Frequently Asked Questions
What resistance value should an earthing report show?
No single value applies to every installation. Criteria depend on system type, protection arrangement, method and applicable standard.
Is an earthing test the same as an electrical inspection?
No. Earthing measurement may be one part of a wider electrical inspection that also covers panels, protection and connections.
Is an earthing design needed for an inspection?
The Ministry's 2025 notice says the installation design is required for periodic earthing inspection.
How often should earthing be measured?
Confirm intervals from regulations, applicable standards, installation type and operating conditions; do not assume one interval for every system.
What if a measurement is not acceptable?
Verify method and connections, correct potential system defects and perform a scoped reinspection after the work.
Official sources and further reading
- Ministry: periodic inspection procedures and electrical installation criteria
- Ministry: electrical, earthing and lightning-protection report criteria
This article is for general information. Confirm document names, application steps and current requirements with the relevant authority, utility and applicable regulations.
