The Cisco N9K-PAC-650W-B is a 650 W rack AC power supply for the Nexus 9300 platform, and its airflow direction is port-side exhaust. Cisco's ordering table is explicit about the pair: N9K-PAC-650W is port-side intake and N9K-PAC-650W-B is port-side exhaust, so the B suffix here denotes exhaust, not intake.
Airflow direction: get this right or the switch cooks
Airflow has to match the hot and cold aisles of the rack the switch is going into, and a supply blowing the wrong way is a returns event rather than an inconvenience. Cisco documents the same intake and exhaust pattern on the 1200 W members of this family: N9K-PAC-1200W is port-side intake and N9K-PAC-1200W-B is port-side exhaust. Within the power supply family the B suffix is consistent and it means exhaust.
The fan modules invert the same letter
Fan modules on this platform use the opposite convention to the power supplies, which is the single most valuable thing this page can tell a buyer. Cisco lists NXA-FAN-30CFM-F as forward airflow, meaning port-side exhaust, and NXA-FAN-30CFM-B as reverse airflow, meaning port-side intake. A B power supply and a B fan module therefore blow in opposite directions.
| Part | Suffix | Airflow direction |
|---|---|---|
| N9K-PAC-650W | None | Port-side intake |
| N9K-PAC-650W-B | B | Port-side exhaust |
| NXA-FAN-30CFM-F | F | Port-side exhaust |
| NXA-FAN-30CFM-B | B | Port-side intake |
Never infer airflow direction from a suffix letter across part classes on the Nexus 9300 platform. Read the direction from Cisco's own description of the specific part number, and confirm that the supplies and the fan trays fitted to one chassis agree with each other before the switch is racked.
Condition, testing and what ships
Supplies are refurbished Cisco parts carrying the original part number, tested on receipt and tested again on the bench before despatch. Parts including power supplies carry the 1-year Enterasource warranty, and shipping is free FedEx Ground to the lower 48 states. Airflow direction is confirmed against your chassis and rack orientation at the time of quotation rather than assumed from the code on the order.
Compatible platforms and related switches sit in the Cisco networking hardware range, including the Nexus 9372TX. The wider switch catalogue is under Cisco switches.
Frequently Asked Questions
Does the B suffix on a Nexus power supply mean intake or exhaust?
Exhaust. Cisco's ordering table lists N9K-PAC-650W as port-side intake and N9K-PAC-650W-B as port-side exhaust, and the same pattern applies to the 1200 W members of the family. This is worth stating plainly because the opposite assumption is common and because the fan modules on the same platform use the letter the other way round.
Can a B power supply be paired with a B fan module?
Not if consistent airflow is the goal. On this platform NXA-FAN-30CFM-B is reverse airflow, meaning port-side intake, while the B power supply is port-side exhaust. Pairing them puts opposing air paths in one chassis. The matching fan for a port-side exhaust supply is the F module, which Cisco describes as forward airflow, port-side exhaust.
How much power does this supply provide?
Six hundred and fifty watts of AC output, which is the lower of the two ratings Cisco offers on this Nexus 9300 supply family; the other is 1200 W. Both ratings are available in intake and exhaust variants, and the choice between them is driven by the switch model, the number of powered ports and whether the design calls for supply redundancy.
What condition are your refurbished Cisco power supplies in?
Every supply is tested electrically on receipt before it enters stock, then cleaned and inventoried. It is tested again on the bench immediately before despatch, in the configuration it is being shipped in. Cosmetic condition is graded per unit, and any physical defect found during either test pass is recorded against that specific part and published on its listing.
