Okay, let's break down why you might not be getting 123A for a 480V, 3-phase load using 35 kVA and 44 kVA, and how Notes 1, 2, and 3 (if you can provide them) are probably affecting things.1. The Basic Calculation

The fundamental formula for calculating 3-phase current is:`I = kVA / (√3 V)`Where: `I` is the current in Amperes (A) `kVA` is the apparent power in kilovolt-amperes `V` is the voltage in Volts `√3` is the square root of 3 (approximately 1.732)

Calculations without considering notes



For 35 kVA

I = 35,000 / (1.732 480) = 35,000 / 831.36 = ~42.1 A

For 44 kVA

I = 44,000 / (1.732 480) = 44,000 / 831.36 = ~52.9 ASo, just using kVA and voltage, you're nowhere near 123A. This is why the additional information (Notes 1, 2, and 3) is crucial.

2. The Importance of Notes 1, 2, and 3 (This is the key!)

Without knowing what Notes 1, 2, and 3 say, it's impossible to give you a definitive answer. However, here's how those notes could be affecting the calculation: Note 1: Demand Factor/Diversity Factor

This is VERY common. The note might say something like, "Apply a demand factor of X%" or "Use a diversity factor of Y%." This means that the load doesn't actually draw the full 35 kVA or 44 kVA continuously. It might only draw a percentage of it.

Example

If Note 1 says, "Apply a demand factor of 50% to the 35 kVA load," then you'd use 35 kVA 0.50 = 17.5 kVA in your calculation. That's a HUGE difference.

Note 2: Power Factor (pf)

This is another common factor. Loads with a power factor less than 1.0 draw more current than their kVA rating would suggest. The formula becomes:`I = kVA / (√3 V pf)`

Example

If Note 2 says, "Power factor = 0.8," you'd divide the previous current calculation by 0.
8. This increases the current.

Note 3: Motor Load Considerations (Starting Current)

If the load includes motors (especially large motors), Note 3 might address inrush current or locked-rotor current. Motors draw significantly more current when they start than when they're running. This starting current may need to be factored into the calculation, especially if you're sizing breakers or conductors. The note might specify to use the motor's full-load amps (FLA) rating or a percentage of it. It might even specify to use the locked-rotor amps (LRA) for short-circuit protection.

How to Approach the Problem When You Have the Notes


Write Out the Formulas

Start with the basic `I = kVA / (√3 V)` formula.2.

Incorporate the Power Factor

If Note 2 mentions a power factor (pf), modify the formula: `I = kVA / (√3 V pf)`3.

Apply the Demand/Diversity Factor

If Note 1 specifies a demand factor (DF), multiply the kVA by the demand factor before using it in the formula: `I = (kVA DF) / (√3 V pf)`4.

Motor Load Calculations (Note 3)

If the load includes motors and Note 3 gives specific instructions for motor loads, follow those instructions carefully. This might involve: Looking up the motor's FLA in tables based on horsepower and voltage. Using a percentage of the FLA for sizing conductors. Using the LRA for sizing overcurrent protection.5.

Sum the Loads

If you have multiple loads (the 35 kVA and 44 kVA), and the notes tell you how to combine them (e.g., apply different demand factors to each), do that before calculating the total current.6.

Calculate the Total Current

After applying all factors and adjustments from the notes, perform the final calculation to determine the total current.

Example with Hypothetical Notes

Let's assume the following hypothetical notes: Note 1

35 kVA load has a demand factor of 60%. 44 kVA load has a demand factor of 80%.

Note 2

Power factor is 0.85 for both loads.

Note 3

The 44kVA load is a motor; use 125% of the motor's full load amps (FLA) for conductor sizing. (We need to find the kVA/HP to FLA conversion). Assume the motor is 50 HP.

Calculations


Adjusted kVA

35 kVA load: 35 kVA 0.60 = 21 kVA 44 kVA load: 44 kVA 0.80 = 35.2 kVA2.

Current for 21 kVA Load

I = 21,000 / (1.732 480 0.85) = 21,000 / 706.65 = ~29.7 A3.

50 HP Motor Full Load Amps (FLA)

Using a standard motor FLA chart for 460V 3-phase motors (this is close enough to 480V), a 50 HP motor is approximately 65A.4.

Current for 35.2 kVA Load (Motor Conductor Sizing)

Use 125% of FLA: 65 A 1.25 = 81.25 A5.

Total Current (Assuming conductors are feeding both loads)

29.7A + 81.25A = ~110.95 A

Important Considerations



Overcurrent Protection

The motor's starting current (LRA) might dictate the size of the breaker. Note 3 might provide instructions on this.

Code Compliance

All calculations must comply with the National Electrical Code (NEC) and any local codes.

Professional Advice

If you are not a qualified electrician or electrical engineer, consult one. Electrical work can be dangerous and should only be performed by qualified professionals.

To get to 123A you would need more load from either 35kva or 44kva.In summary, to get a precise answer, you must* provide the exact text of Notes 1, 2, and 3. They are the key to understanding why you aren't getting 123A. Without that information, I can only give you general guidance. Flag for review