9 Conductors

I am getting ready to install a 500Hp 480volt three phase motor on a piece of equipment powered by a VFD. I will be running 9 conductors to the motor not including grounds. These conductors will be running in 3 - 3/1/2 ridged conduits. What is the best practice to run 3 conductors in each conduit and separate them by phase, Phase 1 in a conduit Phase 2 in a conduit and Phase 3 in a conduit or have conduit 1 running an U1,V1 and W1 conduit 2 running U2, V2 and W2 and conduit 3 running U3,V3 and W3 and then pairing up the U's, U1, U2, and U3. the V's V!, V2, and V3 and the W's W1, W2, and W3 at the motor. Is there Harmonics or EMF generated that should be taken into consideration. The wire is "Tray Rated" 500MCM THHN

by ddt01
May 19, 2020

2 Answers

Answer by Foxx

Just to make sure I understand, you plan on running 3 conductors in parallel for each phase and you have 3 conduit runs. Is this so? If it is, each conduit should carry one conductor from each phase and I would be surprised if whatever code you are working under does not require this. If you put three parallel conductors of one phase in an iron conduit you get a magnetic field induced in the iron which heats the iron quite possibly to a dangerous level and also puts an extra impedance in series with the motor feed. If you are using plastic conduit, situation is not as bad but it is still poor practice

+1 vote
by Foxx
May 19, 2020

Answer by ddt01

Thank You Foxx. That's why I was asking

+1 vote
by ddt01
May 20, 2020

Your Answer

You must log in or create an account (free!) to answer a question.

Log in Create an account

Go Ad-Free. Activate your CircuitLab membership. No more ads. Save unlimited circuits. Run unlimited simulations.

Search Questions & Answers

Ask a Question

Anyone can ask a question.

Did you already search (see above) to see if a similar question has already been answered? If you can't find the answer, you may ask a question.

About This Site

CircuitLab's Q&A site is a FREE questions and answers forum for electronics and electrical engineering students, hobbyists, and professionals.

We encourage you to use our built-in schematic & simulation software to add more detail to your questions and answers.

Acceptable Questions:

  • Concept or theory questions
  • Practical engineering questions
  • “Homework” questions
  • Software/hardware intersection
  • Best practices
  • Design choices & component selection
  • Troubleshooting

Unacceptable Questions:

  • Non-English language content
  • Non-question discussion
  • Non-electronics questions
  • Vendor-specific topics
  • Pure software questions
  • CircuitLab software support

Please respect that there are both seasoned experts and total newbies here: please be nice, be constructive, and be specific!

About CircuitLab

CircuitLab is an in-browser schematic capture and circuit simulation software tool to help you rapidly design and analyze analog and digital electronics systems.