Wiring three phase: Oxtools/BarZ approach

[rabler]

Anyone seen Tom Lipton's latest Epic Egress youtube video, and the approach on wiring in the three phase? Basically he wired the whole shop off a three phase panel even though it's currently run off a 30HP RPC. So two legs are driven from the utility transformer and the third leg in the panel is from the RPC. Makes sense to me IF he does go with three phase power from the utility. If he keeps the RPC, I think I prefer having the 3 phase self contained from the single phase. But, I hadn't even thought of that approach ...

 

[FOMOGO]

I watched it this morning, and found the 3phase panel setup interesting. Too late for me, as my panel is in and a have a 3phase breaker panel for my converter waiting for me to get to it. If I was just starting it would be something to consider. Not sure if that meets code or not, but don't see why it wouldn't.

 

[C-Bag]

I also watched that partially because watch everything Tom puts out, but also because shop power is something I’ve been contemplating. The one thing I was surprised by was that his well pump was not 3ph. Not that I’m any kind of expert but the two we’ll pumps I was exposed to were 3ph. That’s how my FIL got 3ph into his shop. Tom mentioned that there was a 3ph pole tantalizingly close, but who knows how much PG&E would charge to run him 3ph.

 

[woodchucker]

I didn't see anything surprising, seemed pretty basic. Having watched Stan help other guys he is very good about this. His business is doing industrial buildings, setting up ---- you name it---- so he's quite savvy on wiring. I guess I didn't know enough to realize it was unusual.

 

[rabler]

. I guess I didn't know enough to realize it was unusual.

More of a "wish I'd though of that" than saying it is unusual. And then going on to figure I'd probably keep my current config even if I'd thought of it. I only have 2 or 3 three phase machines, and lean toward VFDs for the smaller stuff so don't expect that to grow radically even if I do get more. But it is rather elegant.

 

[C-Bag]

I thought it was interesting that the only job of that big 30hp phase converter was to generate the third leg. But don’t know enough beyond that to just wonder…..

 

[woodchucker]

well, that's all a rotary phase converter does, is generate the 3rd leg.
That's all mine does. I have 2 legs, and by spinning that motor, I get a 3rd leg.
I don't have a 3phase breaker box, nor do I need one. I only have one machine currently.
But if I had a number of pieces of equip and knew I'd buy and sell equip as needed, I think having the panel makes good sense.

 

[rabler]

I thought it was interesting that the only job of that big 30hp phase converter was to generate the third leg. But don’t know enough beyond that to just wonder…..

That's all an RPC really does. The other two legs are just passed through from the single phase.

I guess in the end it is just a question of how many single phase (120/240) vs 3 phase breakers you use, since you don't want to pull single phase power off the generated leg with an RPC, but no reason not to (in fact it's better for load balancing) if you have utility line 3 phase.

 

[C-Bag]

well, that's all a rotary phase converter does, is generate the 3rd leg.

Well I just learned something I didn’t know. I just assumed it was like a vfd and generated all three, doh!

 

[rabler]

Bad thing in that configuration would be that you could put a single phase breaker on your generated leg (i.e., in the wrong slot on the panel), and it would not pull 120V but would give you around sqrt(3) * 120V = 208V when the RPC was running.

I guess this is classic high leg delta, so shouldn't be a problem for an experienced industrial electrician, but a DIY Joe shop owner might run into trouble with this. Maybe @Bi11Hudson will weigh in with some thoughts.