Stray Current Study
Investigation of current flowing outside its intended conductor — through structural steel, pipework, cable armour or earth — which causes corrosion, interference and touch-voltage hazards. Stray current is usually a symptom of an installation defect rather than a phenomenon in itself.
What this study establishes.
Measurement of current in earthing conductors, structural steel, pipework and cable armour.
Identification of the mechanism — neutral-earth interconnection, DC traction, cathodic protection, insulation failure.
Assessment of corrosion risk where DC stray current is present.
Neutral-to-earth voltage and current survey across the distribution system.
Touch voltage assessment on affected metalwork.
Remediation plan — separation of neutral and earth, bonding correction, or insulating joints.
What the work covers.
Investigation of current flowing outside its intended conductor — through structural steel, pipework, cable armour or earth — which causes corrosion, interference and touch-voltage hazards. Stray current is usually a symptom of an installation defect rather than a phenomenon in itself.
On a TN-C-S installation the most common finding is neutral and earth interconnected downstream of the separation point, which sends a share of the load return current through the bonding network. It is an installation error, not a system characteristic, and it is straightforward to find once looked for.
What lands in your inbox.
Measurement of current in earthing conductors, structural
Measurement of current in earthing conductors, structural steel, pipework and cable armour.
Identification of the mechanism
Identification of the mechanism — neutral-earth interconnection, DC traction, cathodic protection, insulation failure.
Assessment of corrosion risk where DC stray
Assessment of corrosion risk where DC stray current is present.
Neutral-to-earth voltage and current survey across the
Neutral-to-earth voltage and current survey across the distribution system.
Touch voltage assessment on affected metalwork
Touch voltage assessment on affected metalwork.
Remediation plan
Remediation plan — separation of neutral and earth, bonding correction, or insulating joints.
How we run it.
Scope & data capture
We confirm the question the study must answer, agree the measurement or modelling points, and collect what the work depends on: earthing and bonding arrangement including the tn system type in use; location of dc sources — traction, cathodic protection, rectifiers, pv; corrosion history on buried or bonded metalwork.
Measurement & modelling
Engineers carry out the measurement and modelling on site and in software, under operating conditions representative of the problem rather than a single convenient snapshot.
Analysis against standard
Results are assessed against IEC 60364-5-54, EN 50162, IEEE 142, with the assessment basis and any measurement uncertainty stated rather than implied.
Report & recommendations
You receive a signed engineering report with findings ranked by consequence, the reasoning behind each conclusion, and mitigation options costed so they can be acted on or deferred deliberately.
Assessed against the published limits.
Common questions.
Typically in one of these situations: unexplained corrosion on pipework, structural steel or buried services; measurable current in bonding conductors that should carry none in service; tingle or touch voltage reports on metalwork. If none of these apply, the study is unlikely to be the right next step and we will say so.
To scope and run the work we need earthing and bonding arrangement including the tn system type in use; location of dc sources — traction, cathodic protection, rectifiers, pv; corrosion history on buried or bonded metalwork. Where any of it is missing we can establish it on site, which changes the scope rather than blocking the work.
Primarily IEC 60364-5-54, EN 50162, IEEE 142, IEC 62305-3. The applicable framework depends on your connection agreement and jurisdiction, so we confirm which applies before measurement rather than after.
Ready to start the engagement?
Tell us about your site and the problem you are seeing. We come back with a fixed scope, a fixed fee, and a named lead engineer.