---
title: "readAttributeRmsVoltageSwellPeriodPhaseC(completion:)"
framework: matter
role: symbol
role_heading: Instance Method
path: "matter/mtrbaseclusterelectricalmeasurement/readattributermsvoltageswellperiodphasec(completion:)"
---

# readAttributeRmsVoltageSwellPeriodPhaseC(completion:)

## Declaration

```swift
func readAttributeRmsVoltageSwellPeriodPhaseC(completion: @escaping @Sendable (NSNumber?, (any Error)?) -> Void)
```

```swift
func readAttributeRmsVoltageSwellPeriodPhaseC() async throws -> NSNumber
```