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PROTECTIVE EQUIPOTENTIAL BONDING. 411.3.1.2

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"Dad?"

"Yes son"

"Have you noticed the extra words added to the bonding regulation, 411.3.1.2?"

"No, what are they?"

"The regulation now says with regard to extraneous-conductive-parts, they need bonding if they are LIABLE TO INTRODUCE A DANGEROUS POTENTIAL DIFFERENCE"

"Why have those words been added Dad?"

Z.

Parents
  • 0

    How can an extraneous-conductive- part introduce a dangerous potential difference into an installation? It is normally at Earth potential.

    The key concept there is potential difference, rather than absolute potential. If all the other metalwork inside your installation is at say 115V or 230V (even briefly due to an earth fault during clearance times, or for a longer duration, say due to a broken PEN conductor), then a part held at true earth potential creates a hazardous potential difference, across which someone could receive a fatal shock.

       - Andy.

Reply
  • 0

    How can an extraneous-conductive- part introduce a dangerous potential difference into an installation? It is normally at Earth potential.

    The key concept there is potential difference, rather than absolute potential. If all the other metalwork inside your installation is at say 115V or 230V (even briefly due to an earth fault during clearance times, or for a longer duration, say due to a broken PEN conductor), then a part held at true earth potential creates a hazardous potential difference, across which someone could receive a fatal shock.

       - Andy.

Children
  • 0 in reply to AJJewsbury

    So it is not just the extraneous-conductive-part that is hazardous on its own. On its own it may be quite harmless. It is only hazardous in combination with other aspects within an installation. The wording should make this situation clearer.

    Z.

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