In brief
- A rod in the ground proves nothing until someone measures its resistance and the reading is written down.
- Concealed joints and rod tops get buried first, so inspect the electrode, the clamp and the pit before backfilling.
- Ask who did the work, how the depth and conductor size were decided, and what test equipment they carry.
Contents
An earthing installation in Burao is only as good as the person who sets the rod, tightens the clamp and records the reading. The fault path exists on paper but not in the ground, so a fault may fail to trip the circuit breaker quickly.
What do earthing installation skills gaps look like in Burao?
The gap shows first in the decisions made before the rod goes in. A competent installer reads the specification, then picks the rod material, length and burial depth to suit it.
Watch for these workmanship defects:
- The rod top sits too shallow or too deep against the drawing, with no record of why.
- The conductor from the main earthing terminal to the rod is undersized, or a different size from the one specified.
- Clamps are hand-tight, mixed metals touch directly, or the joint sits where it needs corrosion protection. Confirm from the site investigation whether the pit bottom sits below the water table, and apply the corrosion protection the specification requires.
- The pit is filled with rubble and no inspection cover, so the connection can never be opened again.
- The test link or disconnection point is missing, so resistance cannot be measured later.
None of these are visible after the slab goes down. The check belongs before backfilling, against the project specification, not after the client reports a shock.
Why does this gap weaken fault protection?
In a fault, current runs from the live conductor into exposed metalwork, then through the earthing conductor and the electrode to the earthed source or neutral point. That loop must stay low enough in impedance for the protective device to operate. When resistance is high, the fault current is small, the device may not trip, and metal parts of the installation can stay live.
Resistance depends on soil resistivity, rod length, rod diameter, moisture and contact between rod and soil. Sandy or rocky ground pushes resistance up. General practice is to drive deeper, use multiple rods spaced apart, or use a conductor laid in a trench. The actual depth, spacing and conductor size must come from the project's specification and the engineer, not from a rule remembered on site.
A second gap is testing. An earth resistance tester used without the correct leads, spacing or a reference reading gives a number that means nothing.
How do you check the work before it is covered?
Attend the inspection before backfilling. Walk the route from the main earthing terminal to the pit and compare what is installed with the drawing.
Ask these questions on site:
- Which specification clause sets the rod depth, material and conductor size, and can the installer point to it?
- What is the measured earth resistance, who measured it, and with which instrument and calibration date?
- Are the clamps the correct type for the metals joined, and are they tight and protected against corrosion?
- Can the rod and the connection be re-opened later through an inspection pit?
- Does the installation connect to the lightning protection and to the main earthing terminal as the drawing shows?
The electrical supervisor, not the client, should hold the answers. If no test record exists, ask for a repeat test witnessed by the supervisor, and keep the result with the as-built drawings.
What to do next
Request the rod depth, conductor size and clamp type in writing from the contractor, then attend the test and photograph the instrument display, the rod top and the connection. File the reading with the as-built drawings.
Frequently asked questions
Can I accept an earthing installation without a resistance test?
No. The rod and joints are buried after backfilling, so a reading taken then is hard to repeat. Ask for the test before backfilling and keep the recorded value with the as-built drawings.
Why does the earth resistance reading change after the rains?
Soil moisture lowers resistance, so a reading taken in wet ground can look better than the dry-season value. Note the date and ground condition with every reading so the dry-season figure is known.
Local reporting: this article is written for building work in Burao and Somaliland. Ground conditions, prices and rules differ between places; confirm the details for your own site.