How Should a Transformer Be Earthed (Grounded)?
Quick answer — A transformer tank and fittings are earthed to ensure the metal is at earth potential and to carry any fault current back, protecting people and the network. Body/earth grounding uses a low-impedance connection (often copper) to the station earth mat; the neutral is earthed (solidly, or via an impedance) depending on the system. Bonding, low resistance and regular checking are essential.
How should a transformer be earthed?
What is earthed
The tank, the core and clamping frames, the bushings are earthed (sometimes via a core earth/connection), and the neutral is earthed according to the system.
Why it matters
Earthing keeps the tank and fittings at earth potential so no dangerous voltage appears on the enclosure, and it provides a return path for fault current to operate the protection.
Good practice
Use a low-resistance conductor and reliable connections to the earth mat, bond all the metal parts, and test the earth (and the core/neutral earth) regularly. A poor earth is a safety and protection risk.
References & standards
- IEC 60076-1
- IEEE C57.12.00
Related
Related manufacturers
Prolec GE (GE Vernova) · Prolec GE Waukesha · Hitachi Energy USA · Siemens Energy · Eaton · Virginia Transformer Corp
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Technical content is prepared from engineering references, standards frameworks, manufacturer documentation and industry sources. Contractual or compliance decisions should refer to current official standards. TransformerPath Technical Editorial.
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