I used an online US cable voltage drop calculator:
Voltage Drop Calculator - https://www.calculator.net/voltage-drop-calculator.html?necmaterial=copper&necwiresize=4&necconduit=steel&necpf=0.9&material=copper&wiresize=0.4066&resistance=1.2&resistanceunit=okm&voltage=208&phase=ac3&noofconductor=1&distance=50&distanceunit=feet&eres=60&x=43&y=23&ctype=nec
For 50ft of 6AWG for the Rottler cable run the voltage drop between start and end at 60A is 2.44V. You can see now how the voltage drops in the transformer (4.66V) and cabling (2.44V) are adding up to cause the problem of low voltage at the Rottler. 208- 4.66- 2.44 =
201V
You may have to run another triple of the same 6AWG (or thicker but not thinner)cables parallel (electrically and physically) to reduce this to 1.22V. Or replace by one thicker complete cable run sized to achieve 'good enough' voltage drop at 60A.
See:
Voltage Drop Calculator
This is a calculator for the estimation of the voltage drop of an electrical circuit. The "NEC data" tab calculates based on the resistance and reactance data from the National Electrical Code (NEC). The "Estimated resistance" tab calculates based on the resistance data estimated from the wire size. Click the "Other" tab to use customized resistance or impedance data, such as data from other standards or wire manufacturers.
Result
Voltage drop: 2.44
Voltage drop percentage: 1.17%
Voltage at the end: 205.56
The calculation result above is based on alternating current resistance and reactance data of 3-phase, 60 Hz, 75°C from National Electrical Code (NEC). The actual voltage drop can vary depending on the condition of the wire, the temperature, the connector, the frequency etc.
Wire material | Copper Aluminum | Wire size | 14 AWG 12 AWG 10 AWG 8 AWG 6 AWG 4 AWG 3 AWG 2 AWG 1 AWG 1/0 AWG 2/0 AWG 3/0 AWG 4/0 AWG 250 kcmil 300 kcmil 350 kcmil 400 kcmil 500 kcmil 600 kcmil 750 kcmil 1000 kcmil | Material of conduit | PVC Aluminum Steel | Power factor (PF) | |
Voltage | | Phase | DC AC single phase AC 3-phase | Number of conductors | single set of conductors 2 conductors per phase in parallel 3 conductors per phase in parallel 4 conductors per phase in parallel 5 conductors per phase in parallel 6 conductors per phase in parallel 7 conductors per phase in parallel 8 conductors per phase in parallel 9 conductors per phase in parallel | Distance (one-way) | feet meters miles kilometers | Load current | Amps | | |
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