High AC Magnetic EMF Emanation - House Wiring Puzzle

[Curiousphy]

Hi, please see attached image below. Do you know why the indicated outlet, out of everything in this mess of a circuit, has particularly high AC Magnetic EMF emanation? The wiring inside the outlet box looks normal and standard (2 neutrals on left, 2 hots on right, grounded correctly, no ground to neutral connection), I even replaced it with a different receptacle, same phenomenon. It's also not caused by external fields, because disconnecting the latter part of the circuit brings the field back down to normal.

What physical phenomenon could explain this? Thanks!

 

[AZFIREBALL]

What are the red wires at the smoke alarms and the red wire at the switch and outlet just below the alarms? And is the fan light always on?

 

[Curiousphy]

The red wires are the signal wires for the smoke alarms. The red wire at the switch below the alarms controls the split receptacle. When the fan lights are on, the field at the problem receptacle goes up to >4 mG. When they are off, the receptacle is at 0.9 mG. If the smoke alarm hot line is disconnected, it falls to 0.2 mG. I would have expected all receptacles prior to the alarms to exhibit the same characteristic, but no, it's just that one receptacle... but when you look inside the box, there's nothing special or wrong about it..

 

[Tom.G]

In that 'problem' receptacle, try twisting the insulated portion of the Black and White wires around each other.

 

[davenn]

What physical phenomenon could explain this? Thanks!

A total abortion of a wiring layout, that's what ... OMG ... that would have electricians rolling over in their graves.
I have never seen something so bad ( and I'm not talking about the drawing).

#1 rule, you should not have power outlets on the same circuits as lighting
give them separate circuits and circuit breakers
and considering all your outlets are double sockets, I would strongly suggest that they be divided into at least 2 sections 2 x lots of 4 outlets each group with their own breakers

Get your wiring sorted out and THEN see if any of your other problems still exist

D

 

[anorlunda]

As others said, there are serious errors in this wiring. Errors that could injure or kill. This is definitely a case where a professional electrician is worth the cost.

But we do not give professional advice here on PF. Thread closed.