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?
Something to do with gas and sparks perhaps? My father worked on the Isle of Grain oil refinery many years ago during its construction. The early works were disrupted by the 1953 tidal floods of the area. There are interesting reports and photos of the flooded area in the local newspapers in the heritage resource library in Rochester near to the bridge.
This is just a length of ladder in a plantroom carrying armoured cables. It is not extraneous, it is not used as a CPC. My thought was that the braiding is superfluous and your responses give me heart that I am not alone.?
..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)
Glad to hear it. Sadly, almost every specification I see does, and these are specs from big multinational companies.
I’ve worked on plants with gas, coal and other nasty stuff. The only time a bonding jumper would be used would be a break in the continuous run of the ladder. Not that that mattered, the support brackets would be welded to the plant structure.
