Power 8 Power Requirements
IBM Power 8 power requirements by machine type: rated voltage, maximum watts, thermal output in BTU per hour, weight and rack units for the 8286-41A, 8286-42A, 8284-21A, 8284-22A and the 8247 L-models, including the DC-powered variants.
Power 8 is the generation where the power supply feature, not the model name, decides what voltage the machine will accept. Two 8286-42A systems can sit side by side with different supplies and different electrical requirements. This page gives IBM's published electrical rating for every Power 8 machine type this site tracks, and flags where the supply choice changes the answer.
Power 8 power requirements by machine type
IBM published electrical and physical ratings, Power 8 scale-out family
| Machine type | Model | Operating voltage | Max power | Max thermal | Weight | EIA |
|---|---|---|---|---|---|---|
| 8284-21A | Power S812 | 100 - 127 or 200 - 240 V ac | 1,225 W | 4,180 BTU/hr | 28.6 kg | 2U |
| 8247-21L | Power S812L | 100 - 127 or 200 - 240 V ac | 1,225 W | 4,180 BTU/hr | 28.6 kg | 2U |
| 8284-22A | Power S822 | 200 - 240 V ac, or 192 - 400 V dc | 1,810 W | 6,176 BTU/hr | 28.6 kg | 2U |
| 8247-22L | Power S822L | 200 - 240 V ac, or -48 to -53 V dc | 1,810 W ac | 6,176 BTU/hr ac | 28.6 kg | 2U |
| 8286-41A | Power S814 | 100 - 127 or 200 - 240 V ac (900 W), 192 - 400 V dc (1400 W) | 1,420 W | 4,845 BTU/hr | 43.8 kg | 4U |
| 8286-42A | Power S824 | 100 - 127 or 200 - 240 V ac (900 W), 192 - 400 V dc (1400 W) | 2,300 W | 7,848 BTU/hr | 43.8 kg | 4U |
| 8247-42L | Power S824L | 100 - 127 or 200 - 240 V ac (900 W), 200 - 240 V ac (1400 W) | 2,300 W | 7,848 BTU/hr | 43.8 kg | 4U |
All models are single phase at 47 to 63 Hz. Voltage entries in brackets name the power supply wattage that range applies to. The 8247-22L in its DC-powered form is rated at 948 W and 3,235 BTU/hr rather than the AC figures shown. Source: IBM Power 8 server specifications.
The 900 W against 1400 W supply distinction is the trap on this generation. An 8286-42A with 900 W supplies will run on a 120 V circuit. The same machine type with 1400 W supplies takes 192 to 400 V dc instead. Buying a used S824 on model name alone tells you nothing about which of those two machines is arriving on the dock. Get the power supply feature code in writing before the truck is booked.
What a Power 8 actually draws
IBM filed measured power figures for Power 8 under the earlier EU ecodesign regime, and the coverage is far thinner than for Power 9 onward. The one machine type in this family with a cleanly published measurement is the 8284-21A, and it is instructive.
IBM measured idle and maximum power, Power 8
| Machine type | Model | Sockets | Measured idle | Measured maximum | Rated maximum |
|---|---|---|---|---|---|
| 8284-21A | Power S812 | 1 | 283.5 ... 313.5 W | 295.9 ... 370.8 W | 1,225 W |
Range runs from IBM's tested low-end configuration to its tested high-end configuration, declared operating condition class A2. Source: IBM Technical Documentation for EU Regulation 2019/424. Other Power 8 machine types have no cleanly readable filing, so no measured figure is published for them here rather than an estimate.
An S812 measured at 370.8 W flat out against a 1,225 W rating means the machine never asks for more than a third of what the circuit is built to give it. The same ratio broadly holds across the family, which is why a rack of Power 8 machines almost always has more electrical headroom than the nameplate arithmetic suggests. It is also why replacing Power 8 with Power 10 or Power 11 rarely requires electrical work.
Reading the power supply out of a machine you own
From the HMC
Managed system properties lists installed power supplies with their part numbers and status. This is the fastest way to tell a 900 W machine from a 1400 W one without opening the rack.
From IBM i
WRKHDWRSC *CMN and the service tools hardware listing report the enclosure and its installed features. DSPSYSVAL QPRCFEAT gives the processor feature, which drives where in the load range the machine sits.
From the chassis
Power supply CCIN and part number are printed on the supply itself. On a 2U machine the supplies are rear-accessible and readable without downtime, which makes this the reliable check before a relocation.
From the PDU
Measured amps at the outlet under real workload is the only number that reflects your configuration. Everything published here is the boundary that measurement sits inside.
Planning the room around a Power 8 you intend to keep
Circuit sizing follows the rating
An 8286-42A at its 2,300 W rating on a 208 V feed draws about 11.1 A. With the standard 80 percent continuous-load derating that fits a 20 A circuit per feed with real margin, and a redundant supply pair wants two feeds from separate sources.
Cooling follows BTU
One ton of cooling removes roughly 12,000 BTU/hr. Two S824s at 7,848 BTU/hr each is more than a ton and a quarter before storage, network or console hardware is counted.
Supply age is the real risk
Every Power 8 supply is now well into its service life. A machine that has quietly lost redundancy runs fine until the surviving supply fails. Confirm both supplies are present and healthy, not just that the machine is up.
The 47 to 63 Hz range is wider than later machines
Power 8 accepts a broader frequency band than Power 9 onward, which narrowed to 50 or 60 Hz plus or minus 3 Hz. On generator or unstable utility supply this is one of the few areas where the older machine is more tolerant, not less.
Sources: IBM's Power 8 server specifications for the ratings, and IBM's EU Regulation 2019/424 technical documentation for the measured figures.
Confirm which machine type you actually have on Identify Your Power 8, then check the processor feature against the Power 8 CPU reference and the supply part against the part and feature code directory. If the room is the reason you are considering a move, the Power 8 migration options and the end of support position cover the rest of that decision. For the cross-generation facilities walkthrough see AS400System.com's Power server power requirements guide.