SWA Gland (correct termination of)

[Keef]

Topic of much debate...
Is there reasons to fit the earth tag on the inside of the metal enclosure? The one about preventing corrosion does not wash with me as the enclosure is not IP68 rated thus cannot protect from corrosion inside.
I have always been taught to fit brass tag on the outside with a brass nut and bolt to prevent electrolytic corrosion. If you fit brass tag on the inside you get brass(tag)-mild steel(enclosure)-brass(tag)-zinc plated nut. Not a good mix especialy when adorned with another mild steel roofer!
Any oppinions welcome, this could be a big can of worms though. DISCUSS...

 

[boatnik1]

I would always have fitted the tag on the outside because that gives the best contact between the brass gland and the tag. Wether the tag is bolted with a brass or galv bolt shouldn't really make any difference to the connection as the bolt only holds the tag as tight as possible to the box unless you are fitting a secondary tag to the bolt for an earth connection within the box and in this instance a brass bolt is preferable . It's hard to see where the bolt type would make any difference to galvanic/electrolic action as the bolt is going to be making the same contact to a galv box either way, as is the tag. In an area of salt air the galvanic/electrolytic action will be increased and in these areas a non metalic box is preferable with all tags/earth connections within the box.
Once all connections are tight on a galv box I have found it advantagous to paint the outside of the box with hammerite and put a bead of silicone around the lid and holding screws and also around the exposed armour to seal the gap within the gland, but that is because a lot of my work has been around the local harbour. Also always fit the supplied boot.

 

[ian.settle1]

Another reason why it is fitted on the outside is that it can been seen without having to open up the enclosure it is glanded to see if it is fitted.