IrishSparky
New member
Can piping each of the wires in a three phase feeder in separate pipes cause overheating?
Three Phase piped separately
- Thread starter IrishSparky
- Start date
- Status
- Location
- Massachusetts
Yes and in most cases will be a code violation.
patriot
Member
- Location
- Chapmansboro,Tn.
Why would you want to pipe them separate?
- Location
- Massachusetts
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
How do the EGC's get sized when separated this way? The same as if they were in the conduits with the CCC's?
masterinbama
Senior Member
- Location
- Huntsville Alabama
In the right circumstances it can make things much easier.
Iwires picture looks like a service with a reduced neutral.
- Location
- Massachusetts
I have done isolated phase installations at least two or three times but they were always services not feeders.
- Location
- Illinois
- Occupation
- retired electrician
The arrangement of the EGC will not change for an isolated phase installation. An EGC will be required in each raceway if the circuit is a feeder, and if the ungrounded conductors are run in parallel 250.122(F) will apply.
patriot
Member
- Location
- Chapmansboro,Tn.
In the right circumstances it can make things much easier.
Would'nt that cause exessive heating of your conductors?
That doesn't heat the conductors, it heats metal in between the conductors. The more current the more heat. It's like the core of a transformer, almost. Thats why you can't use metal pipe or metal enclosures unless you cut a slot in the metal between the pvc conduits.
- Location
- Illinois
- Occupation
- retired electrician
This arrangement does increase the impedance of the conductors and does cause some additional heating over what you would have in a conventional installation. It does not cause excessive heating unless you encircle one or more sets of conductors with ferrous materials.
And I have seen pictures of the damage that was caused in an installation like this were steel strut and strut straps were used to support and secure the non-metallic raceways.
And I have seen pictures of the damage that was caused in an installation like this were steel strut and strut straps were used to support and secure the non-metallic raceways.
I don't immediately see how.
Sure, the spacing will increase the impedance but that's because the inductance will increase - a bigger loop. The L part, not the R. And mostly, the heat generated in a conductor is from the R part.
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