Grounding chain recommendations

[LaSalle1940]

I need guidance/recommendation for specifying a grounding CHAIN (yes, I said "chain", not cable). This would be installed in an atmospheric vessel that will contain molten sulfur. The point is to ensure that the potential between the nozzles where the molten sulfur enters by gravity and the volume of molten sulfur are equal such that no sparks are generated by static electricity as the molten sulfur falls from the nozzles into the liquid volume contained.

As far as I know, the NEC is silent on the nature of grounding chain. As best as I can tell, for the only application I know of--namely, over-the-road tank trucks--it would appear that common carbon steel chain is used. That would seem to work here, since the vessel in question is itself carbon steel. But I need something to back up this recommendation. Thanks.

 

[itsmoked]

You are going to (oh yeah burning sulfur is a problem isn't it!) run the chain from the nozzle into the vat of sulfur,(like those chain gutter downspouts), or from the nozzle to the side of the vat? I am trying to understand the logic of not using cable. Temperature? I believe that very hot things don't need to worry about static since the work-function would have unbalanced charge spewing everywhere, (but I could be easily dissuaded of this). Liquid sulfur is an insulator?

But back to the chain. I don't think you are going to find much on the topic because it is butt-simple. You are bleeding a very tiny current pushed by a high voltage down that chain. Hence no heating, no serious current = no spec. The chain is really chosen by the user to handle the mechanical venue.

Keith Cress
Flamin Systems, Inc.-

http://www.flaminsystems.com

 

[dan769]

I think the temperature of the chamber and sulfer are your only restraints on material choices.
I have done a lot of work in "Low NOISE Low Current" measurements (femto & atto amperes) and have found using braided wire/cable to be the best choice for grounding conductors.
Braided wire is inexpensive and therefore easily replaceable component in your chamber.