Break out the pocket protectors and slide rulers for this one. How much CEMF is acceptable in a lighting circuit? I'm trouble shooting a lighting system thats all track lighting. Recently a section burnt up at the coupling and the track, and it supposed a good quality track. Due to its troubled history, I am looking at every angle.
In my research and testing, I discovered a slight unbalance of 0.15 amps via amp clamping all the conductors in the conduit without the grounding couductor.
Is there a way to quantify the resistance of the circuit that is unbalanced? There are two circuits in the conduit with its own grounded conductor. The circuit that the track failed has no measurble CEMF. The second circuit is the one that is reading 0.15 amps. Being that it is in the same conduit as the ciruit that failed, It will affect it some. The big question is is the affect big enough to be concern about?
Even though we may look at a manufacturer as being high quality, they're still bound to occasionally throw a weak product out there. The couplings/wiring connectors are usually the weakest link in any track lighting set up. Most track I've come across is rated for 2400w but I've never pushed any near that far... I've seen receptacles that can be snapped into lighting track just like a fixture, leading me to believe the mfrs have quite a bit of faith in the stuff..
It's not a case of over thinking. I'm confident in my findings. It's a trivial question at best. I'm addressing every possible angle of failure for a report. There is a long history with this system. If it is not documented, it did not happen. I'm just trying to quantify all my findings for my report.
The question is more about CEMF and its affects and less about the track lighting
0.15 is a small amperage. If you are using a clamp meter, it would be tempting to test the accuracy by doubling the loop through the clamp.
If there is a fault to ground, 0.15 amps at 120 volts is about 18 watts. That much heat should be detectable by touch if it all happens at one place. You could try a megger at 250 volts to confirm the problem and pull the lights off the track to eliminate them as a cause.
0.15 amps to ground at 120 volts suggests a ground fault of about 800 ohms, or two faults of about 1600 ohms. It isn't hard to imagine a couple or two with dirt or arcing to be the cause.
I also had problems with track lights that failed at the couplings. It turned out that the ceiling moved when people walked on the second floor.
Let me rephrase my question. Taking the track light out of the equation, how much CEMF, or back emf is too much to cause problem like wires overheating? For example, there is 5 amps unbalance measured in a circuit. It there a way to calculate the impedance of the circuit based on that 5 amps measured?