I believe it was only to split the load. It is a three position switch Turned one way it is on to both terminals and the key cannot be removed. Center is off. Turned the other way is on to both terminals but the key can be removed.

IRWIPI 2005 Peoples Choice
Inky,
"It's not that I haven't done IT... It's that I haven't done IT yet."

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'48 1-1/2 ton Dump
'57 Chevy Panel
'59 Chevy 2 ton Dump