Combined Power on MS Devices

Overview

Combined Power allows switches with two power supply modules draw power from both modules at the same time.

Switches with two power supply modules are designed to use them in redundant mode. In this setup, only one module powers the switch at a time, while the other stays on standby to take over if the first module fails.

The second power supply module, called Combined Power, provides PoE power up to its maximum rated limit while acting as a standby power supply for the switch control system. If the primary power supply module fails, the secondary module maintains uninterrupted power to the switch and adjusts PoE power provisioning as explained in the "Power Budgeting with Combined Power" section.

Combined Power Supported Models: MS350, MS355 and MS390 Series. MS390 switches always operate in Combined Power mode.

Configuring Combined Power

To configure the power mode, go to Switch > Configure > Switch Settings. Select either Redundant power or Combined power as the default power supply setting for the switches in your network. If some switches should not use the default setting, assign them to a power mode using custom lists in the power supply settings exceptions section.

This option is available only when the switch has two power supply modules installed and powered. It applies to switches running firmware MS 11.0 or later.

Power Budgeting with Combined Power

Switch Family	Switch Model	Combined Power Budget
MS350	MS350-24P	720W
	MS350-48LP	740W
	MS350-48FP	1440W
	MS350-24X	1440W
MS355	MS355-24X	1440W
	MS355-24X2	1440W
	MS355-48X	1480W
	MS355-48X2	1480W
MS390	MS390-24P	720W
	MS390-24U	1440W
	MS390-24UX	1440W
	MS390-48P	1152W
	MS390-48U	1800W
	MS390-48UX	1590W
	MS390-48UX2-HW	1745W

The switches budget power based on the PoE device classification. The budget can exceed the available power to estimate the total power that might be used. Devices will keep receiving power until consumption exceeds the available power or a power supply module fails. If a failure occurs, lower port numbers have priority, and power will be cut from higher port numbers, denying them power.