How to add Enphase Power Control System (PCS) MPU Avoidance Mode to Lyra projects in order to avoid a main panel upgrade
By adding an Enphase Power Control System (PCS) MPU Avoidance Mode to arrays, designers can install a main panel tie-in and avoid main panel upgrades for larger projects that normally would require a main panel upgrade.
Prerequisites:
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Project is on NEC 2020, NEC 2023, or CEC 2022
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Project has a Enphase partial home backup configuration
During the Electrical BOS step, simply select the interconnection method Main Panel Tie-In: Standard load-side tie-in. MPU Avoidance Mode to be activated with current limited to xA (the amperage will be project specific). See example below.
How it looks in the single line diagram
Between the microgrid interconnect device (MID) and the PV system disconnect you'll find a new note in pink that states "PCS set to MPU avoidance mode and current limited to xA" (the amperage will be project specific). See example below.
Real life example
Here we have an example project with the following characteristics:
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Main Service Panel with 200A busbar and 200A main breaker rating (found in the properties panel when the MSP is selected)
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Total array current output of 149.7A (found in the Electrical Design step)
Without PCS, the maximum current output that would be compatible with a main panel tie-in is 32A. Lets review the 120 rule, (busbarA *1.2) - MBR = xA. xA cannot exceed 125% of AC output current. For this example that'd look like: (200A *1.2) - 200A = 40A, 32A * 125% = 40A). Our example project far exceeds this limit.
With PCS, the AC current output is limited to 32A in this case via equipment software, allowing for a main panel tie-in without a main panel upgrade.