Cisco 3750's Adding Power Stack Cables

[MichaelGrech46995]

I have inherited a network that has Catalyst 3750's stacked with the data cables, but the power stack cables were not installed.  The stacks have only two switches per stack and only one power supply in each switch.  Essentially no power redundancy.  I have the power stack cables and want to know if I can install them while in production without consequence.  Or do I need to shut the stack down, connect the power cables, then powerup.  l hope I don't have to do it that way but will.

[Leo Laohoo · Accepted solution]

What is the exact model of the switches and what is exact model of the PS installed. 

I would never use power-stacking cable if, for example, each switch only has ONE x 375wac power supply (750wac for PoE).  If the each switch member has 1100wac PS, then power stacking make sense. 

[MichaelGrech46995]

The switches are Catalyst 3750-X and each switch has an 1100-Watt Power supply.  They are POE switches.

[MichaelGrech46995]

Are there CLI commands to include the power stacking?

[Leo Laohoo · Accepted solution]

StackPower Cabling Configurations

[Joseph W. Doherty · Accepted solution]

For redundancy, you need to carefully analyze power needed if a PS fails.  For example, with your 1100, is that enough to support all your load on two switches with their PoE devices?

Second, I recall there's a limitation to how much power the power cables can carry.  You might find, for example, the cables might not support two 1100 in one stack member and none in the other stack member (of course, not something you would likely do, but, again, pointing out there are cable amperage limitations).

So for redundancy, for your dual 1100, you might want to add a 750 to one, or possible both, switches; or another 1100 to one switch member (again, much depends on you actual power needs and cable limitations - a power stack isn't a chassis power design).