The Bomb Aimers Panel
The bomb allocation and distribution panels used to fuse each of the 16 bomb stations separately and determine which order the bombs dropped from the bomb bay.
You can see the Nose/Tail Bomb Fusing switches (centre top) and the Bomb Bay station selection switches (top left).
Bottom left is the Bomb Release Control (or Intervalometer) which permitted bomb aimer to control the number of bombs dropped per release and their release spacing.
The picture is from ...
https://www.lancasterraf.co.uk/inside-tour/
The wire you refer to is the final arming device of each bomb,as the bomb drops clear -the wire pulls out a pin which has been locking the arming propeller,the propeller then starts turning in the airflow and completes the arming of the bomb on the way down to its target.
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