anltechnical
New member
- Location
- USA
wires in conduit are not hot!!!
Non-zero net current flowing in the wires inside a ferromagnetic (iron, steel) conduit will cause inductive heating in the metal of the conduit. But that normally requires a pretty high current to be noticeable.wires in conduit are not hot!!!
Wires in conduit can get hot. Wires in no conduit can get hot. That is why there are rules about wires in the NEC.wires in conduit are not hot!!!
Non-zero net current flowing in the wires inside a ferromagnetic (iron, steel) conduit will cause inductive heating in the metal of the conduit. But that normally requires a pretty high current to be noticeable.
I've seen 80% loaded conductors cause a conduit to get warm. And it has been warm for years. 90 degree's F.
Agreed.Note that the OP states that the wires are not hot but the conduit is hot. I am assuming that means that the wires are not as hot as the conduit and so it is not possible that they are the sole source of the conduit itself heating up.
But, in this case according to the OP, are not hot.Wires that are loaded do give off heat.
wires in conduit are not hot!!!
I observed the same thing when I took part in wiring one of those huge mail-order warehouses. I sure I could have circled the earth several times with all the wire I pulled.
The point is that, even without an 'load' to speak of, but with all the circuits powered up, SOME raceways were noticeably warmer than neighboring conduit. These pipes contained wires for a multitude of sensors, readers, and solenoids - everything went to the PLC cabinet.
Fast forward to today, where I daily deal with "wires" that stay rather cool (maybe 'only' 180 degrees F) while they make neighboring steel hot enough to glow and even melt.
The secret lays in the fluctuating magnetic field of the electricity flowing through the wires. It's not current, really - it's much more about frequency. Kick the frequency up to a few thousand cycles, and nearby steel starts getting hot.
This is the same principle used in the new "induction" ranges - where the pot gets hot, but the cooktop does not. (Well, not as hot as the pot does!)
An inductive range uses a multi-turn coil around the core. Inductive heating in a conduit will be at most a single turn.a
First thing that came to my mind too. 3 phase installation requiring parallel conductors, but done by an amateur having one conduit holding all Phase A, one with Phase B, one with Phase C, instead of one of each phase in each conduit.I only seen a hot conduit once where a contractor had tried to pull isolated parallel phases in EMT like we do with PVC, he didn't know it would be a problem, but that was a long time ago.
was line side and load side of each circuit passing thru the same nipple? Even one common line conductor and several switched load conductors still has cancelling effect as the line conductor is carrying the same current as the sum of the load conductors.I've seen instances where a load management system was installed with lots of single-wires going through the same nipple causing the conduit to get noticeably warm.