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Hello, I'm working on a project where there's a non-conductive pipe with wires carrying electricity running through it. I'm attempting to connect this pipe to another pipe, like a cross (x), and I was thinking of using magnetism to connect them. Will magnets affect the electric current inside the non-conductive pipe?
Question Date: 2013-07-19
Answer 1:

Thanks for sending us your interesting question! Magnetic fields always impact charged particles that are in motion (i.e., electrical currents - the flow of electrons through a wire), but do not have an impact on stationary charges (for example, the electrons that are sitting stationary in wires that are not connected to electrical sources). In fact, magnetic fields are also generated by the motion of charged particles, so wires that have electrical current flowing through them can actually deflect a compass needle. The following pages (from NASA) do a nice job of introducing the relationship between electricity and magnetism: Magnetism and Magnetic Fields.

As for your question: Yes magnetic fields are going to have some impact on the electric currents that are flowing through the wires in your project. Depending on the orientation of your wire(s) in relation to the magnet(s), the most likely effect will be to cause a very slightly reduction in the efficiency of current flow through the wires. A (somewhat oversimplified) way to think about this is to first imagine that current is flowing through a wire with no magnetic fields around. In this case, the electrons can flow down the center of the wire without bumping into the walls very often. However, when the wire is placed into a magnetic field, some of the electrons will be deflected from the center of the wire by the magnetic field and end up colliding with the walls of the wire: the electrons end up "bumping through" the wire, which is less efficient than flowing down the center. The number of electrons that are deflected from the center of the wire will depend on the relative orientation of the wire to the magnetic field.

Above, I put "very slight reduction" in italics and underlined because the impacts of magnetism are small enough to be unnoticed in day-to-day applications, like your project. In general, the two special cases when magnetic effects become important enough to consider are: 1) in very high magnetic fields (for example, MRI machines at hospitals or highly specialized research tools) or 2) near very large electrical currents (for example, the electrical wires that bring electricity out of power plants).

Good luck with your project, and please feel free to send us more great questions!

Answer 2:

You are right to think that magnets can effect currents flowing through wires. They absolutely do. But if you have a magnet near a wire, you are just biasing nudging the electrons in that wire ever so slightly off course. The name for this is the Hall Effect. (You can learn more about it here: Hall effect)

The electrons will still flow through the wires with no problem. Additionally, the magnetic field from a magnet dissipates with distance, and so unless the magnets are almost directly touching the wires, they will likely have no effect at all. In either case though, I don't think you'll notice any effect at all... you're good to go!

Answer 3:

A constant magnetic field won't affect current in a wire. A changing magnetic field, such as if you are moving the magnet around, will induce a voltage in the wires, but it will be extremely small.

Answer 4:

I don't entirely understand how you plan on connecting these pipes, but I can still answer your question.

Magnets will affect the electrical current inside the non-conductive pipe, and vice versa. Moving charges, aka current, produce a magnetic field around them. The natural law concerning electrical currents producing magnetic fields is known as Ampere's circuital law. The magnetic field produced may attract or repel the magnets you use to join your pipes. However, I doubt the magnetic field generated by your current-carrying wires will be strong enough to affect the magnets. A typical small bar magnetic has a strength of 10 milliTesla (mT). If you're using rare-earth magnets they may have a strength of about 1,000 mT. A wire carrying 1 Amp of current (a lot of current, or enough to kill you) will generate a magnetic field approximately 0.1 mT at distance of 1 cm from it. Consequently, your magnets will be much more occupied with each other than with the whatever field the wire is putting out.

Keep in mind that if you move your magnets relative to the wire you will induce another electrical current that may or may not complement the current already flowing. This phenomenon is a story for another day, but if you want to read more about it look up Faraday's law of induction.

Keep questioning,

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