# Unison ER4 Max Current Draw

## 120VAC Calculations

Given an input of 120VAC, the ER4 will draw a maximum of 8 Amperes -- 2 Amperes per option module or processor.

ETC recommends feeding the ER4 with a dedicated 15 or 20A breaker or disconnect.

Given that the Power (Watts) does not change for higher input voltages, we can use the formula W=VA (or P=IE) to determine max amperes at other voltages.

W= |
VA |
---|---|

W= | 120(8) |

W= | 960 |

W= | VA |

960= | 230(x) |

x= | ~4.2 |

Voltages other than 120VAC

The ER4 will draw a maximum of 4.2 Amperes at 230VAC. A CME will draw approximately a maximum of about 1.1 Amperes at the same voltage.

Using the same calculations at 277VAC, the ER4 will draw a maximum of ~3.5 Amperes at 277VAC. A CME will draw appoximately .875 Amperes at the same voltage.