---
type: Monitoring Guide
title: "How to Monitor Power Supply (PSU) Health via SNMP"
description: "Read PSU electrical values from ENTITY-SENSOR-MIB and status enums from the vendor MIB, and alert on redundancy loss while the system is still up."
resource: "https://snmp-monitoring.info/monitoring/hardware/power-supply/"
tags: [monitoring]
timestamp: 2026-07-11T00:00:00Z
---

# How to Monitor Power Supply (PSU) Health via SNMP

Read PSU electrical values from ENTITY-SENSOR-MIB and status enums from the vendor MIB, and alert on redundancy loss while the system is still up.

## Related concepts

- Up: [SNMP Hardware Monitoring: Temperature, Fans, Power & RAID](/monitoring/hardware/index.md)

## Frequently asked questions

### Can SNMP monitor power supplies?

Yes. Electrical values — watts, input volts, amperes — come portably from the ENTITY-SENSOR-MIB (1.3.6.1.2.1.99), and PSU presence, OK/failed status and redundancy state come from the server's vendor enterprise MIB under 1.3.6.1.4.1. Together they give a full picture of PSU health.

### How do I detect a failed redundant PSU?

Enumerate the PSUs the chassis should have, poll each one's status enum and electrical output, and alert whenever any single PSU reports not-ok, not-present, or zero output — even though the system stays up on the remaining supply. Don't tie the alert to availability, because a redundant server shows no outage when one PSU dies.

### What OID is PSU wattage?

Power output is an ENTITY-SENSOR-MIB sensor typed watts, with its reading in entPhySensorValue (1.3.6.1.2.1.99.1.1.1.4). Input voltage is a voltsAC/voltsDC-typed sensor in the same table. The exact index for a given PSU is device-specific.

### Is PSU status standardized in SNMP?

Mostly no. The electrical values are standardized in ENTITY-SENSOR, but the presence and OK/failed status enums are vendor-specific, living in enterprise MIBs (iDRAC, iLO, etc.). There's no single universal PSU-status OID, so pull the enum from your vendor's MIB.

## Source

Concept generated from https://snmp-monitoring.info/monitoring/hardware/power-supply/ — the SNMP Monitoring vendor-neutral knowledge base. Content is limited to what that page states (no external claims added here).