Saw this recently on site, there is a bond across every cable ladder joint. I do not believe that this is necessary as this is not an exposed-conductive-part or an extraneous-conductive-part. Am I right?
..and yet almost every specification I see calls for it...
Mine don't - except where the containment system has deliberate fishplate joints for variable angles to be adopted, where the ladder or tray may be discontinuous and where I actually wan to introduce a bond (if the containment is extraneous)
In a previous life I had the opportunity to be involved in some cable ladder tests - just adding bonds to splice joints might just achieve about 0.12% improvement in conductivity over a substantial length. Credibly loosing all the connections one side is highly unlikely.
We also hit the containment with test currents in the 80kA region - both with and without links - no credible differences recorded.
If it's put in using proper materials and workmanship, the bonding links don't have any useful purpose. The requirements however are still in such places as US based standards, UL certification and a host of glabal company standards
..and yet almost every specification I see calls for it...
Mine don't - except where the containment system has deliberate fishplate joints for variable angles to be adopted, where the ladder or tray may be discontinuous and where I actually wan to introduce a bond (if the containment is extraneous)
In a previous life I had the opportunity to be involved in some cable ladder tests - just adding bonds to splice joints might just achieve about 0.12% improvement in conductivity over a substantial length. Credibly loosing all the connections one side is highly unlikely.
We also hit the containment with test currents in the 80kA region - both with and without links - no credible differences recorded.
If it's put in using proper materials and workmanship, the bonding links don't have any useful purpose. The requirements however are still in such places as US based standards, UL certification and a host of glabal company standards
