Joetools,
As mentioned by the other Members, "Shielding" the Conductors is an effective method to reduce field emissions.
Shielding may be achieved by encasing Conductors in a Metallic Sheath, and by twisting the Conductors.
The Wiring methods performed on an installation, should have an overall result which balances the current flowing through any given Circuit, in a certain raceway or Cable.
This is stated as "Currents Canceling Each - Other's Fields".
A Two- Wire Circuit cancels the fields because each Conductor draws the same level of Current, but the Currents are flowing in opposite directions at any given point along the Two - Wire Circuit.
For example, a 120V 1200 Watt Heater connected with 12-2 NM Cable, will have 10 Amps flowing on the Black Conductor and the White Conductor.
Since these Currents are flowing in opposite directions at any given time, AND the Currents are of equal value on both Conductors, the Fields are canceled.
If the same Heater was connected to some other 2 wire Circuit's White Conductor, this would cause an imbalance of Current flowing in both of the affected 2 wire Cables, and thus would not cancel out the Fields completely.Let me know if you need more descriptions.
*** SIDE NOTE ***
If someone pulls out their "Field Sniffer" (milli gauss meter) to take field strength readings, be sure they know how to use it correctly!
Taking readings at very close proximity to ANY Discharge Lighting Devices (Fluorescent Lamps, HID Lamps, even CRT Televisions and possibly LEDs) will result in high level readings on ANY Meter!
Same will happen with Transformers and such.
The levels will rapidly drop as the distance increases.
Scott
Last edited by Scott35; 03/04/10 05:25 AM.
