PROTECTIVE EQUIPOTENTIAL BONDING. 411.3.1.2

Question

"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.

gkenyon · Answer

There could well be an extraneous-conductive-part that is NOT liable to introduce danger. For example, if a metal pipe is converted to plastic within a very short distance - say 5 cm - of entering the building volume from the ground, contact with the short metal part is highly unlikely - the risk is further reduced if the floors are wooden, the metal is hidden away somewhere, and there is no risk of simultaneously touching it and any other conductive parts connected to the MET. So, in addition to being very difficult to effect a suitable bonding connection, bonding it would serve no purpose. Note that in the same Regulation, the "insulating section" wording is now gone.

PROTECTIVE EQUIPOTENTIAL BONDING. 411.3.1.2

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