I am trying to replace an old spotlight with a new one. The problem is that the cable coming out of the wall is very short - only about 10cm. The earth was trimmed off rather than being sleeved so it is even shorter - 5cm at most. The new spotlight has the white plastic connector fixed into the base, and the cable from the wall just won't reach There is no slack in it at all to pull more through. Is there any way to safely extend the cable?