Want to trace mains wiring by putting EMF on earth/ground pin

Thread Starter

seanspotatobusiness

Joined Sep 17, 2016
190
I am trying to trace electrical wiring in a brick wall and my wiring detector is not detecting it. I followed a tutorial to make an EMF detector to use with a compact fluorescent light which supposedly generates EMF on the wiring but this did not work. I bought an actual EMF detector but it only detects the wiring of a CFL if it's in physical contact. Would it be difficult/practical to make a circuit which I can connect to the earth pin of my socket to produce stronger EMF which I can then trace with my EMF detector?
 

crutschow

Joined Mar 14, 2008
23,526
A standard AC lamp dimmer will often put a lot of EMI into the wire, especially if you turn it down to about 1/2 brightness with a large wattage bulb.
A nearby AM radio tuned off-station will give you a good indication of how much EMI it is generating.
 

Thread Starter

seanspotatobusiness

Joined Sep 17, 2016
190
A standard AC lamp dimmer will often put a lot of EMI into the wire, especially if you turn it down to about 1/2 brightness with a large wattage bulb.
A nearby AM radio tuned off-station will give you a good indication of how much EMI it is generating.
Thanks. Do you mean a dimmer for use with an incandescent bulb?
 

Thread Starter

seanspotatobusiness

Joined Sep 17, 2016
190
Unfortunately, the EMF drops off too quickly and isn't detectable after <2 cm. I'm not able to detect it through the wall. I think I'm going to need a way to deliberately generate a large EMF. Is it not feasable to generate a large EMF through a ground/earth wire?
 

MaxHeadRoom

Joined Jul 18, 2013
19,192
There are fairly cheap cable detectors that inject a signal into the circuit, if you know the breaker source of the wiring you are trying to detect, it could be used by ensuring the breaker is off and the signal injected into the cable.
Or it could be done with each circuit in turn.
An example is the TG20 (DigiKey).
Max.
 

Janis59

Joined Aug 21, 2017
812
There are some well working ideas:
1) probably Your cabling is those old-days wrapped in alumina or steel or even lead braiding. Thus the EMI are not going out of it. Solution - turn into Your detector the metall regime. Check which regime is active. Mine Bosch have separate wood, iron, non-magnetic and details under voltage regimes. Its so easy to switch on the wrong one.
2) disconnect a electricity. Check if it is well done. Solder the 100 kHz meander oscillator (just RC and three digital NOR elements), modulate it by 400 Hz on/off. This signal must be connected between real GND and one of the search cabling wires. Other is small search coil with opamp and loudspeaker, in which will be easy to hear those 400 Hz. This is very sensitive thingy working so far as some 10-20 cm at max sensitivity. At Biltema chain-shops as well the ebay such complects cost about dollar or slightly more.
3) use a 50 Hz capable EMI measurer, it senses the wires about 1/2 meter afar or if under current then few meter afar. Precise placement would be appreciated by maximum field figures.
4) make a small coil with few thousand of turns, put the diode in series or better the Greinacher multiplier circuit (two diodes, two capacitors) and measurre DC by sensitive tester. There will be milivolt tenths.
5) instead of tester apply the headsets, no diodes, no capacitors. Instead of coil may be used old days open type telephony relays, just cut off all the cantacture so the nude coil with main core be left. The 100 Hz sound will be dull so far as quarter of meter off the wire.
6) Use just the touristic compass. Near the wire with surrent it will become "stiff". The AC component is bit too fast to see the vibrating, but it will badly sense the Earth field and no respond to the slow rotation in hand. The know there is another current around it.
7) use the iron nanopowder some miligrams on the glass plate. Near the wire under current ir will become alive and dribble. Voltage alone have no such effect. However this method is weak working for supersymmetrical two-line cabling.
 
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