Will a Faraday Cage protect a Magnetic Compass from electrical deflection?

[JumbleDuck]

Radiation from a conductor called electromagnetic radiation comes in 2 forms electromagnetic radiation and electrostatic radiation. ...

You are confusing fields and radiation: there are electric fields (which arise from any charge, whether moving or not), magnetic fields (which arise from any current, AC or DC) and electromagnetic radiation which contains time-varying electric and magnetic field at right angles to each other. Electric field can't penetrate conductors. Magnetic fields can penetrate conductors (but not superconductors, for other reasons) but are blocked by high-permeability materials. Electromagnetic radiation is generally blocked by conductors, but can get through holes of around its own wavelength or bigger - which is why light gets through the small holes in the front of a microwave oven but microwaves don't.

The point of the helicopter chaps suit, by the way, is simply to provide an alternative path for current that doesn't involve the squishy bits inside. Shielding from electric fields is a secondary effect.

 

[Len Ingalls]

Just a wee point here.. twisting wires isnt perfect, its good, but not 100%
The problem is due to the fact that the cores are not in exactly the same place as each other, close, but no cigar. An improved solution is a different style of cable, namely star-quad where the cores are laid at the corners of a square and then twisted. Each diagonal pair forms 1 conductor, the average location of which is at the centre of the bundle, same as the other conductor. Yet another improvement is to add a 5th core in the middle of the square and connect this to the cable screen.

Would coax (with shield grounded) for each wire help?

or a shielded multi wire cable?
/ Len

 

[JumbleDuck]

Would coax (with shield grounded) for each wire help?

Good point: there's no magnetic field outside a coaxial cable.

 

[William_H]

Perhaps Jumble Duck is correct on terminology.
Re using coax cable or shielded cable there is no magnetic field particularly static magnetic field from DC because the 2 conductors are effectively in the one place so fields produced cancel one another. A bit like twisting the wires together. The screen does nothing to stop magnetic field. olewill

 

[JumbleDuck]

Re using coax cable or shielded cable there is no magnetic field particularly static magnetic field from DC because the 2 conductors are effectively in the one place so fields produced cancel one another.

Coax cable produces no magnetic field because the current distribution is symmetrical. The same doesn't apply to shielded cable: the magnetic field produced will be exactly the same as if the shield wasn't there.

 

[William_H]

Coax cable produces no magnetic field because the current distribution is symmetrical. The same doesn't apply to shielded cable: the magnetic field produced will be exactly the same as if the shield wasn't there.

Ah terminology again. I had in mind shielded single core cable (you might call it coax) while I think you have in mind multiple cored shielded cable. Yes multicored shielded cable will have a (static) magnetic field exactly as if the shield were not there. Coax to me implies a cable of specific RF impedance ie 50 or 75 ohm. But that may just be my terminology regards olewill