My hubby is a radio amateur and took EE courses for fun at GA Tech (he was a Chem major but all his friends were EEs) and he'd never heard of Wiggy (I googled it and saw it's been around since 1918), he's always used Fluke.
Here's a report I ran across -- Undocumented Electrical Jumper Causes Mild Shock
An electrician performed a safe condition check with a portable voltage tester, commonly called a "Wiggy," and no voltage was found. The electricians started work and found two wires supplying the receptacle. An additional safe condition check with a Wiggy was performed to verify that no voltage was present. The cover was then removed from a junction box in that circuit, and a third safe condition check was performed with a Wiggy. No voltage was indicated. The electricians disconnected the receptacle from the existing wiring, removed the receptacle box from the wall, and installed the new receptacle. While making the final terminations, an electrician felt a "tingle" in his hand. Work was stopped, and another safe condition check was performed with a Wiggy. No voltage was indicated. Another check was performed with a high-impedance (Fluke) multimeter, and 111 volts were found in the outlet wires. . . . The initial voltage checks failed to detect electric potential in circuit #6 because the high impedance of the transformer limited the current flow to less than that detectable by the Wiggy voltage tester.
Somebody ought to slap whoever put the jumper on there though!
This guy never would have made a lineman.