3-Phase 4-Wire Sub Panel panel form a 1-Phase Risidental Panel?

[vaaoc1425]

I like to know whether it is technically correct to provide a 3-phase 4-Wire panel from a residential single phase panel which I assume which has L1 and L2 and a Neutral.

I was asked to provide a 60 amp sub-panel form a residential panel which I assume 100 Amp or larger. I had a choice of providing a 60 amp single pole breaker in the residential panel to feed the 60 amp sub panel OR provide a 30 amp three pole circuit breaker to feed the 60 amp sub panel.

I am confused as to whether it is technically correct in providing a three pole 30 amp circuit breaker to feed the 60 amp sub panel. The 60 amp sub panel may have five 20 amp circuits totals less then 40 amps. Unfortunately I didn’t have a chance to make a site visit to this moment.

Thank you in advance.

 

[wbd]

First off you can't get 3 phase from 1 phase without a rotary converter, so it is impossible. Next, why can't you feed the subpanel with a 2 pole breaker, this would be more appropriate.

 

[TheBlacksmith]

Would not a two-phase breaker and a four wire cable with two "hot" leads, a dedicated ground lead and a dedicated neutral lead with separate ground and neutral buses in the sub-panel be correct?

 

[tinfoil]

The two hots on a 1 phase house service are 180deg out of phase. THERE IS NO SIMPLE WAY TO CONNECT THIS TO GET THREE PHASE POWER.

A 30amp 3ph circuit breaker should NOT be used from a 1ph panel to supply 60a 1ph load.

 

[advidana]

You better have an electrical engineer look at your project before you get into a jam.

 

[vaaoc1425]

My thread was a "what if", not that I was going to do it.
As I have indicated I also had choice of using a 1-pole 60 amp breaker to feed the sub-panel, which will work I am sure. Also as I have mentioned, I have not had a chance to verify the main panel in person, so the thread was again "what if"!

Thaks for all your info, I have decided to use a 2-pole 30 amp brekaer to feed the sub-panel. I am sure this will work.

 

[waross]

One of my pet peaves;
Reversed polarity vs. 180 deg. out of phase.
When I hear the single, center-tapped transformer winding supplying a single phase service referred to as "180 deg, out of phase" I think that it is akin to calling two batteries in series, supplying 12 and 24 volts, "180 deg. out of phase" with each other.
respectfully

 

[tinfoil]

DC batteries do not have any 'phase'.

Have you got a better way to shorthand explain the split-winding grounded-center-tap one-phase connection?

 

[ScottyUK]

Semantics, semantics...

Is 'The two hot lines are in anti-phase' any better?



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Sometimes I only open my mouth to swap feet...

 

[MikeHalloran]

I rather like 'anti-phase'.

Mike Halloran
Pembroke Pines, FL, USA

 

[jraef]

Weren't there Star Trek episodes where people were in "anti-phase" realms, right next to everyone else but unseen and unable to interact?




Am I coming off and a Trekkie geek?