Leveraging Intelligent PDUs and Monitoring: Rack Power Solutions for Modern AI Applications

Overview

The starting point is the density jump: racks that used to run 15-20 kW now exceed 60 kW for AI and can reach 100 kW. The question therefore becomes less how many outlets a PDU offers and more how many kW the inlet plug and circuit can carry. Table 2 converts common high-current inlets to usable kW with the 20 % UL/NEC derating: 208 V 60 A gives 17.3 kW, 208 V 100 A gives 28.8 kW, 415 V 60 A gives 34.5 kW, 415 V 100 A gives 57.5 kW and 480 V 100 A gives 66.5 kW.

IEC-market equivalents follow: 400 V 63 A gives 41.5-43.6 kW and 400 V 125 A gives 82.3-86.6 kW. On the server side, Table 3 lists maximum power: A100 6.5 kW (3+3 PSU), H100/H200/B100 HGX 10.2 kW (4+2), B200 12 kW and MI300X 10.2 kW. Because PSU redundancy may be 3+3, 4+2 or 5+1, the PDU count and per-path load for the same server change with the scheme chosen.

Hardware details get their own treatment. C21 outlets carry the same 20 A/250 V as C20 but with a thermal rating up to 155 C, while Saf-D-Grid and RF-203 support 480/277 V operation. The paper notes that traditional 5 kAIC branch breakers may be inadequate for AI racks and recommends 10 kAIC breakers or fuses. It also cites an ASHRAE supply range of 15-32 C and 20-80 % RH.

Three applications close the calculation. Eight Dell XE8640 servers at 208 V/60 A exceed 60 kW. Six XE9680 servers at 415 V/60 A use 5+1 PSU redundancy and need 4 PDUs, or 6 if PDU redundancy is also required. Temperature, leak and vibration sensors are added to the examples. This is a manufacturer publication using mostly North American figures, so comparison with local rules is left to the reader.

Key points

1. Racks that ran 15-20 kW now exceed 60 kW for AI and can reach 100 kW.
2. Derated inlet capacities: 208 V 60 A 17.3 kW; 208 V 100 A 28.8 kW; 415 V 60 A 34.5 kW; 415 V 100 A 57.5 kW; 480 V 100 A 66.5 kW.
3. IEC inlets: 400 V 63 A 41.5-43.6 kW; 400 V 125 A 82.3-86.6 kW.
4. GPU server maximum power: A100 6.5 kW (3+3), H100/H200/B100 HGX 10.2 kW (4+2), B200 12 kW, MI300X 10.2 kW.
5. C21 outlets match C20's 20 A/250 V with a thermal rating to 155 C.
6. Saf-D-Grid and RF-203 outlets support 480/277 V operation.
7. 5 kAIC branch breakers may be inadequate; 10 kAIC breakers or fuses are recommended for AI racks.
8. 6 x XE9680 at 415 V/60 A with 5+1 PSUs needs 4 PDUs, or 6 with PDU redundancy.

Using it in design

• In the rack-power calculator, offer inlet presets (voltage, amps, plug), apply 80 % continuous derating and show kW per feed.
• Check rack IT load against N+N feed capacity so each path can carry the whole rack alone.
• Catalogue GPU servers with PSU count and redundancy scheme (N+N vs N+M) so PDU count and per-path load compute correctly.
• Flag AI racks using 5 kAIC branch protection and check outlet type against PSU inlet (C19/C20/C21, Saf-D-Grid).

Who should read it

Electrical designers sizing rack power distribution for AI racks above 60 kW.

Related standards

• IEC 60309
• UL 60950/62368
• NEC Article 645
• ASHRAE 90.4

Publication details

Authors

Legrand

Publisher

Legrand

Year

2026

Document number

LIT# V2295 R5

Document language

English

Source type

Manufacturer

Access

Free to read

Licence

Copyright retained; citation only — the publisher’s terms apply to the original document

Citation