It is the earth core.
It is made like that and the core is not itself insulated, in that type of cable.
You need to fit your own G/Y sleeving over it.
However it should be stripped inside of the enclosure rather than outside
that will be, i havent got a 25mm grommet, it's 3 oclock on friday and if i dont finish i wont get paid and cant go down the pub........., but i have got a gland, wayhey!!
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