They may frown on it, but unless a local code prohibits, the NEC allows it.What you really need to do, is go buy a Wire Stretcher.
Danger mouse, it depends on local AHJ if they like that as a fix or not. Some frown on that practice, especially if they have a hair up their rear when inspecting home owner builds or mods to a system.
1. When you stretch a wire, it gets thinner and therefore won't carry as many amperes.What you really need to do, is go buy a Wire Stretcher..