Wondering: If 10A is pushed through a copper wire in steel conduit versus a copper wire inside aluminum conduit, will the steel be more lossier because of it being ferrous and magnetic? Will the conduit heat up more than aluminum?

 

The magnetic field in a conduit (with feeder pairs or phases) from normal utility voltages is minimal. The loss differences are negligible.

 

AC or DC?
Does the return current flow back through the same conduit?
What are the ends of the conduit (electrically) connected to? Does this form a loop?

 

AC or DC?
Does the return current flow back through the same conduit?
What are the ends of the conduit1 (electrically) connected to? Does this form a loop?

AC. The conductor will be shorted and induced with CT to push 10A. Therefore, m each wire will be in a loop. The goal is to start with aluminum and apply same settings to steel to see if it changes. What are your thoughts?

 

Twisted pairs of current carrying conductors effects are self cancelling when twisted together.

 

The NEC usually requires all current carrying conductors of the same circuit to be included in the same cable or conduit.
https://codes.iccsafe.org/s/ISEP201...de-nec-solar-provisions/ISEP2018-NEC-Sec300.3


The fields cancel away from the wire pair.

300.20 (B)
Where a single conductor carrying alternating current passes through metal with magnetic properties, the inductive effect shall be minimized by
(1) cutting slots in the metal between the individual holes through which the individual conductors pass or
(2) passing all conductors in the circuit through an insulating wall sufficiently large for all of the conductors of the circuit.

FPN: Because aluminum is not a magnetic metal, there will be no heating due to hysteresis; however, induced currents will be present. They will not be of sufficient magnitude to require grouping of conductors or special treatment in passing conductors through aluminum wall sections.

 

Twisted pairs of current carrying conductors effects are self cancelling when twisted together.

One wire will be in conduit for this experiment.

 

The NEC usually requires all current carrying conductors of the same circuit to be included in the same cable or conduit.
https://codes.iccsafe.org/s/ISEP201...de-nec-solar-provisions/ISEP2018-NEC-Sec300.3

View attachment 305534
The fields cancel away from the wire pair.

300.20 (B)
Where a single conductor carrying alternating current passes through metal with magnetic properties, the inductive effect shall be minimized by
(1) cutting slots in the metal between the individual holes through which the individual conductors pass or
(2) passing all conductors in the circuit through an insulating wall sufficiently large for all of the conductors of the circuit.

FPN: Because aluminum is not a magnetic metal, there will be no heating due to hysteresis; however, induced currents will be present. They will not be of sufficient magnitude to require grouping of conductors or special treatment in passing conductors through aluminum wall sections.

One wire will be in the conduit for this so called experiment. In a magnetic conduit, what actually heats up? The wire itself or conduit due to hysteresis? Therefore, will the ampacity be affected?

 

One wire will be in the conduit for this so called experiment. In a magnetic conduit, what actually heats up? The wire itself or conduit due to hysteresis? Therefore, will the ampacity be affected?

Do the experiment, tell us what happens. The NEC has rules for a reason, usually.

 

Do the experiment, tell us what happens. The NEC has rules for a reason, usually.

I will perform! What do you think is going to happen? If I have a wire not inside a conduit, 10A through conductor, and place a steel pipe near it, will the steel pipe heat up? Will there be loses associated to the proximity of steel ferrous pipe?

 

I will perform! What do you think is going to happen? If I have a wire not inside a conduit, 10A through conductor, and place a steel pipe near it, will the steel pipe heat up? Will there be loses associated to the proximity of steel ferrous pipe?

Why do you care what I think. The experimental data will show the effects, if any.

 

What do You expect the experiment to demonstrate ???
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What do You expect the experiment to demonstrate ???
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I just want to see the loses for myself. I would like to see if there are ampacity and heat losses. I would like everyones input on the most efficient way of performing tests to achieving this. I plan on posting results.

 

If there were any known, significant losses, there would be readily available
formulas and various online-Calculators to estimate these losses.

Any Inductive or Capacitive, influences or losses, that may be found,
will be so small that they will be very difficult to measure without specialized equipment.

Purely Resistive Wire losses can be estimated using Ohms-Law.
Charts listing Copper-Wire-Resistance for a given length are very common on the Internet.
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One wire will be in the conduit for this so called experiment. In a magnetic conduit, what actually heats up? The wire itself or conduit due to hysteresis? Therefore, will the ampacity be affected?

Sounds like homework,
What do you think will be the difference if anything
What sort of size effect could you expect ?
How are you going to do the experiment to minimise errors?
Please let us know

 

My prediction: At 10A you will see no measurable difference in the voltage across the wire and no noticeable heating.

At 1000A it might be different.

 

What’s the frequency. At 13.5 Megahertz, we had to remove any steel conduit and splice boxes as wires were burning up inside.

 

What’s the frequency. At 13.5 Megahertz, we had to remove any steel conduit and splice boxes as wires were burning up inside.

60Hz. So you saw the significant heating at higher frequencies?

 

60Hz. So you saw the significant heating at higher frequencies?

You wouldn't see it if they were twisted pairs.
Not very often done in conduit where individual/single conductors are ran together.
They are usually pulled in as straight/untwisted conductors..

 

60Hz. So you saw the significant heating at higher frequencies?

Have you done the experiments yet ?