The Trace Wire is a more advanced tracing spell than the tracing spell.
It can locate the approximate location of an underage wizard, and take the underage wizard as the center to detect magic within a certain range around him.
When underage wizards cast spells in the presence of Muggles, the Office for the Prohibition of Misuse of Magic is warned, and a letter is issued directly to those involved. (The first warning Harry Potter received without investigation is a prime example.)
How do traces come about?
Not detailed in the Harry Potter books. [Most of the fandom settings are on the wand, and a bunch of people directly thought that this was the original setting in the book, which is really speechless. ]
The setting of this book is: generated through contract magic,
Original text: A notice was sent to each student, warning them not to use magic during the holidays.
Students at Hogwarts receive a notice from the Ministry of Magic during the summer holidays prohibiting underage students from using magic outside of school. (This leads me to a similar summer vacation notice I signed before, and this is where the inspiration comes from.)
Third-year students need a guardian’s signature to go to Hogsmeade, and this notice signature is not an accident.
This document will carry contract magic, and the Ministry of Magic uses contract magic. Of course, the magic contract is not a prohibition, but a tracking and warning, which forms the surveillance of underage wizards, which is the tracking spell mentioned above.
The Ministry of Magic’s Misuse of Magic Office is notified immediately when underage wizards use magic in an area where Muggles live, or in the presence of Muggles, or when someone uses magic around them.
There is no indication in the Harry Potter books that any traces of underage wizards are related to wands.
They’ll just check the perpetrator’s wand with a flashback spell to see what magic he’s using.
If the trace is related to the wand, I think it’s just a matter of changing the wand and getting rid of the Ministry of Magic’s tracking.
By the way, when you use wandless magic, the Ministry of Magic usually can’t do anything about you, because there is no proof.
When students at the Waggadu School of Witchcraft and Wizardry were accused of violating the International Statute of Secrecy, they had a powerful excuse: I just waved and never meant to dislocate his jaw.
As for Voldemort’s murder of Old Tom’s family, it was not discovered because Morfin Gaunt (uncle) lived in that area, had a criminal record, and confessed to his “crime”.
(Someone is the culprit, or a habitual offender. Naturally, no one suspects it, and Voldemort was already very powerful at that time, and may have the ability to block the traces of the Ministry of Magic.)