---
title: "readAttributeRmsExtremeUnderVoltagePeriodPhaseC(with:)"
framework: matter
role: symbol
role_heading: Instance Method
path: "matter/mtrclusterelectricalmeasurement/readattributermsextremeundervoltageperiodphasec(with:)"
---

# readAttributeRmsExtremeUnderVoltagePeriodPhaseC(with:)

## Declaration

```swift
func readAttributeRmsExtremeUnderVoltagePeriodPhaseC(with params: MTRReadParams?) -> [String : Any]?
```