[Alchemy]

I am setting up a new store and everyone keeps pushing 3 phase power, my total load with a 25% buffer is 21611 watts

I have one machine that the manufacturer specifies as single phase 3 wire 5500wats on a dedicated 3 amp circuit and the other large machine is 3154 watts single phase on a 20 amp dual pole circuit, the rest are common fridges, lighting etc

Is there a need or advantage to 3 phase?

[tkrussell]

I do not think 3 phase is needed for this small load. Have your electrician price the service entrance both ways. Check with the utility for billing charges for both. Compare both costs and make your decision.

[stanfortyman]

If you are in a mall or strip mall it may be required, other than that I highly doubt it.
The advantage to 3-phase is it is much more efficient for motors and similar loads, like A/C units. The other advantage is you get 50% more available power.
A down side is that many 3-phase services are 120/208V delta. This means one out of every three breaker poles is a 208V high leg that you cannot use for 120V loads. So if you have little to no 3-phase loads 1/3 of your main panel will be wasted space, and you'll likely need a sub-panel.

[Alchemy]

If you are in a mall or strip mall it may be required, other than that I highly doubt it.
The advantage to 3-phase is it is much more efficient for motors and similar loads, like A/C units. The other advantage is you get 50% more available power.
A down side is that many 3-phase services are 120/208V delta. This means one out of every three breaker poles is a 208V high leg that you cannot use for 120V loads. So if you have little to no 3-phase loads 1/3 of your main panel will be wasted space, and you'll likely need a sub-panel.

I have a couple of problems,
The install is in an Airport in Mexico, and my spanish is limited, the specialized equipment are both heating units for cooking, but should not be operating continuously, the manufacturer specifies single phase 3 wire. It does give the option of 120/208 or 120/240 on the plate

The original people we had do the plans made so many mistakes I was thinking that the three phase was also a mistake.

[stanfortyman]

Well if the equipment requires 3-phase then you have no choice.

[Alchemy]

Well if the equipment requires 3-phase then you have no choice.

That's my confusion, the plate specifies single phase

[donf]

Just curious, but are you confusing 3 wire with 3 phase?

"3 wire" is a description of a cable.

"3 phase" is the description of the electrical supply to a building.

[Alchemy]

Just curious, but are you confusing 3 wire with 3 phase?

"3 wire" is a descripton of a cable.

"3 phase" is the description of the electrical supply to a building.

No, I wish it were that simple, on the chart of charges the load is balanced between the three phases

[stanfortyman]

That is quite obviously a single phase machine. Whoever suggested otherwise has no idea what they are talking about.

By 3-wire the plate means two hots and a neutral, plus the always required equipment ground.

[Alchemy]

That is quite obviously a single phase machine. Whoever suggested otherwise has no idea what they are talking about.

By 3-wire the plate means two hots and a neutral, plus the always required equipment ground.

Yes that's been my frustration

I just reviewed a pic of the existing panel and I think I know why they are pushing 3 phase, not sure though but I think the unit is already equipped with three phase

[stanfortyman]

That definitely is a 3-phase panel, with one 3-phase branch breaker. Do you know where that goes? HVAC would be my guess.

I have to ask, why is the feeder missing?

[Alchemy]

That definitely is a 3-phase panel, with one 3-phase branch breaker. Do you know where that goes? HVAC would be my guess.

I have to ask, why is the feeder missing?

The blue wires are hvac, not sure what you mean by the feeder,

Would connecting the equipment to 3 phase damage it?

This explains a lot

[tkrussell]

Looks like the 3 pole 40 Amp breaker is the Main Breaker, backfeeding this 3 phase 4 wire 120/208 volt panel.

The feeder conductors seem large, look like #2 copper. I wonder why only 40 amp feeder?

5500 watts at 208 will draw 26 amps. An electrician needs to look at this installation and determine if the existing panel can handle the added 26 amps, plus the existing load, all on a 40 amp feeder.

[stanfortyman]

Looks like the 3 pole 40 Amp breaker is the Main Breaker, backfeeding this 3 phase 4 wire 120/208 volt panel.

The feeder conductors seem large, look like #2 copper. I wonder why only 40 amp feeder?

5500 watts at 208 will draw 26 amps. An electrician needs to look at this installation and determine if the existing panel can handle the added 26 amps, plus the existing load, all on a 40 amp feeder

I got in late last night and read this but did not reply.
I was thinking the same thoughts.

And if this panel is existing what are they talking about with giving him 3-phase, it's already there. Maybe they are talking about an upgrade due to the added load?

[tkrussell]

Yea, who knows, Alchemy needs to consult with an electrician that can review the system.