100 amp circuit II for phase converter.

[930dreamer]

I started a thread a while back on using 2ga aluminum wire for this circuit. I ended up buying a spool of 1/0 copper wire. While in the shop today I had a few questions.

1. If I understand this correctly I can add a 100 amp breaker to the current panel and tap off of that. I want to start/run a 30hp three phase motor for a phase converter(FLA is 71.6 amps on 230v).

2. Can I run off the panel into a 100 amp disconnect (fused)? instead of a main lug or panel? I don't need extra circuits just the 100 amp one.

3. From the converter I would like to feed it into a three phase panel I already have.

 

[930dreamer]

Anyone?

 

[pattenp]

The 1/0 Cu is fine for 100A. A 100A fused disconnect box fed from a 100A breaker in the main breaker panel is fine. From that point on with the 3 phase you're on your own.

 

[930dreamer]

Thank you, do I need a neutral wire for this?

 

[pattenp]

You don't need a neutral for straight 240V. The neutral is only needed to get 120V. I don't know a thing about the 3 phase converter as to if it needs a neutral.

 

[joe_padavano]

You don't need a neutral for straight 240V. The neutral is only needed to get 120V. I don't know a thing about the 3 phase converter as to if it needs a neutral.

If your three phase equipment has any 120V components, you'll need a neutral.

 

[joe_padavano]

A little more info on the 3PH wiring:

 

[930dreamer]

I have a 100 amp disconnect (three phase)that's rated for 15 hp max on single phase 240v & 30hp max on three phase. I want to use it to start a 30 hp three phase motor(idler) on 240v single phase. I know the hp numbers don't match and I have started the motor with this disconnect before.

I'm trying to not cause an electricial issue in my shop, my plan is to run a 100 amp circuit from the main panel with 1/0 copper wire to the disconnect. This will start the 30 hp idler. Do I need to move up to a 200 amp disconnect or is this wiring voodoo? Thank you!

 

[930dreamer]

Any suggestions?

 

[Norcal]

You do not need a neutral w/ a phase converter, & the manufactured phase must not be used for any single phase loads.

NEC Art. 455 covers phase converters, here is a copy & paste of 455.6(B) 2011 edition.

(B) Manufactured Phase Marking. The manufactured
phase conductors shall be identified in all accessible locations
with a distinctive marking. The marking shall be consistent
throughout the system and premises.

Italics added.

My personal opinion is to use orange for the manufactured phase just like the high leg of 240V 3Ø delta but it is not required to use orange....