"HEATING TEST SETUPS
Conduit in Air, EMT in Air
In the heating tests on wires installed in rigid-steel conduit or EMT the wires were laid out in series and folded back on themselves a sufficient number of times to provide the number of wires to be tested. Thermocouples were inserted, as...
I believe you may have missed this part in my post
"SINGLE- VERSUS 3-PHASE HEATING
To determine the effect on conductor heating by single- and 3-phase currents, 12 type RH-RW, no. 6 AWG wires were installed in 2-inch rigid conduit in air, and tested by first using single-phase current and then...
Three phase runs slightly hotter, I finally got my hands on an old AIEE study(IEEE before it was IEEE) that was discussed in the old NEC code panel discussions. I haven't read the study completely though I think my original question may have more to do with what you all were trying to get in my...
Yep, thanks. I don't expect the conductors insulation to degrade or for the conductor to be operating precisely on the table temperature at the specific current in the table, I would expect some safety factor in there.
But a huge concern of mine if you are interested, is time current curves of...
Thanks, this section currently has different and conflicting interpretations in the industry. I would probably still be researching it even if everyone agreed on one interpretation, but it is especially frustrating with different interpretations and methods of application. I have been reading...
Thank you. That makes sense, I was just trying to picture the magnetic fields and thought maybe the three phases 120 degrees apart might produce more heat compared to single phase that decays to zero 120 times a second, while the three-phase system has a strong constant magnetic field. I'm still...
I believe I need to add, I was reluctant to post the code section originally because I am more interested in my core question. I know of many of the industries reasons given for this code section such as load diversification, removing conductor safety factor and because another code section...
When I was thinking about posting on here I was wondering if he specifically, might have an idea. I think he responded to about all of my few threads. I'm an infrequent user and just saw the announcement with this thread, I only corresponded with him a few times but man was he gracious to me...
The allowance is not for how many conductors are in a conduit I could have 6 single phase conductors in one conduit and 6 three-phase conductors in another conduit, same wire and conduit characteristics but I can use a larger overcurrent device on the single phase circuits.
The allowance I am...
I apologize, as you can tell I have a lot to learn. The basis of my question is would a circuit conductor increase in temperature more if it were part of a three-phase circuit than if it were part of a single phase circuit, all other characteristics being the same.
For example, two same size...
Good Morning,
I am not coming up with an answer in my search, could anyone confirm or deny whether a circuit conductor would experience more temperature rise with three-phase current than if the same R.M.S. current was single-phase. Alternating Current, 60 Hertz.
If you want to know why I want...
I agree, i believe i mentioned that in the original post. but there is already another requirement which both the equipment grounding conductor and the ungrounded conductors must both be able to survive the available fault current, so really if each of the grounds need to be that big then the...
I am seeking direction, information, resources and thoughts on the following subject. The common interpretation of the National Electrical Code does not allow you to use multiple smaller equipment grounding conductors in place of one larger one (except in a few cases such as a cable assembly...
i use zinc grease for aluminum, galvanized steal as well sometimes. copper grease just seams like it's a lot better for conductivity, i'll get the DLO out one of these days and check for any real difference.
thanks everyone
do you think copper based grease on the threads of a hot dipped galvanized pipe would likely noticeably(naked eye, no measuring equipment) speed up corrosion of the galvanized pipe in normal environments such as buried in typical soils, maybe slightly more corrosive locations than urban areas...