"Earth Loop" Connections on UK power connector?

I'm looking at a datasheet for a UK power connector. It has connections for Line (brown), Neutral (blue), Protective Earth (green/yellow), and
E1 and E2 (yellow). It describes the E1 and E2 terminals as "2 functional earths (E1, E2) for high integrity "earth loop"". This is something new to me. Can someone describe how E1 and E2 are used?
THANKS!
Harold
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Here you go
http://www.mkelectric.co.uk/case/cases.asp?caseid 06
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Thanks! So how is this wired up, both at the equipment end and the power distribution end? We've got PE, E1, and E2. Do all three connect to the chassis in the equipment? Is the goal here to just have an earth conductor that's three times as large as the line and neutral? Perhaps we're also looking for increased ground (earth) connection reliability through three contacts in parallel (like bifrucated relay contacts)? Or, is there something else going on here.
THANKS!
Harold
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