An Instagram video has gone viral after demonstrating a quick hack electricians use to test a fuse using just a smartphone. The clip, posted by @creationsparkdiy, has now reached 5.2 million views.

If the fuse is blown or the low-voltage breaker is tripped, as will generally be the case in a short, first replace the fuse, or, better yet, use a test breaker, like the Supco Pro Fuse (in place of ...