C13 PDU: Outlet Count, Cord Gauge, and Breaker Check

Auditing a rack power distribution unit requires separating three physical checks that a power cord comparison alone does not cover: individual receptacle current limits and total outlet counts, internal branch circuit breaker bank protection, and upstream input cord or terminal conductor sizing.

On the Legrand 0U Rack PDU, the output provides 20 C13 + 4 C19 outlet connections at 230V with 100 N cord retention and Magnetic Hydraulic (curve D) circuit breaker protection. On the Eaton Tripp Lite PDU1230, (16) C13 and (4) C19 receptacles (15A max per breakered C19 bank; 12A max per breakered C13 bank) are protected by 1 - 10A breaker for the C13 bank and 1 - 15A breaker for the C19 bank. Those two datasheets show why total receptacle count never equals simultaneous current capacity until each outlet bank, branch breaker, and input cable is checked in sequence. For the downstream equipment jumper comparison itself, see the power cord comparison guide.

Check receptacle ratings and outlet counts across form factors

Start the audit by verifying the electrical rating of each panel receptacle and the multi-outlet branch circuit rules that govern continuous current draw.

Under OSHA 1910.304(b)(2)(i), receptacles installed on 15- and 20-ampere branch circuits shall be of the grounding type. Grounding-type receptacles shall be installed only on circuits of the voltage class and current for which they are rated, except as provided in Table S-4 and Table S-5. Under 1910.304(b)(4), outlet devices shall have an ampere rating not less than the load to be served. Under 1910.304(b)(4)(ii)(A), a single receptacle installed on an individual branch circuit shall have an ampere rating of not less than that of the branch circuit. Under 1910.304(b)(4)(ii)(B), on a branch circuit supplying two or more receptacles or outlets, a receptacle may not supply a total cord- and plug-connected load in excess of Table S-4. In Table S-4, for a 15 or 20 amperes circuit rating and a 15 amperes receptacle rating, the maximum cord- and plug-connected load to the receptacle is 12 amperes. In Table S-4, for a 20 amperes circuit rating and a 20 amperes receptacle rating, the maximum load is 16 amperes. In Table S-4, for a 30 amperes circuit rating and a 30 amperes receptacle rating, the maximum load is 24 amperes.

At the component level, the SCHURTER 6600-3 is an IEC Appliance Outlet F with screw-on mounting from the front side and solder or quick-connect terminal. On this appliance outlet, the IEC rating is 10 A / 250 VAC at 50 Hz as an appliance outlet F according to IEC 60320-3. On this appliance outlet, the UL/CSA rating is 15 A / 250 VAC at 60 Hz according to UL 60320-1 and CSA C22.2 no. 60320-1. For cold conditions on this appliance outlet, the pin-temperature is 70 °C (10 A, Protection Class I) and the allowable operation temperature is -25 °C to 70 °C.

For higher-current appliance outlets on mixed units, the SCHURTER 4797 is an IEC Appliance Outlet J with snap-in/screw-on mounting from the front side and solder or quick-connect terminal. On this appliance outlet, the IEC rating is 16 A / 250 VAC at 50 Hz as an appliance outlet type J according to IEC 60320-3. On this appliance outlet, the UL/CSA rating is 20 A / 250 VAC at 60 Hz according to UL 498 and CSA C22.2 no. 42.

The Vertiv Geist Combination Outlet C13/C19 has a 2-in-1 design that connects both IEC C14 and C20 plugs into the same high-retention, P-Lock compatible outlet.

Across horizontal and vertical chassis form factors, published datasheets show how receptacle count scales with input voltage, phase, and ambient temperature rating. MPH2 0-U / 1-U / 2-U form factors list maximum receptacle counts of 48 / 12 / 24; receptacle options include IEC 320 C13 and C19 (also NEMA 5-15 and NEMA 5-20), with 20 A UL489-Listed breakers (5000 A A.I.C).

On single-phase international units, the APC AP7553 output has a 230V nominal output voltage, 32 maximum total current draw, and (20) IEC 60320 C13 plus (4) IEC 60320 C19 output connections. On three-phase international units, the Vertiv Geist VP8881 has a combined total of 42 receptacles, including 36 IEC C13 receptacles arranged as 12 per phase in banks of 6. The VP8881 includes 6 individual IEC C19 receptacles at 230V, distributed at 2 per phase.

Audit branch circuit breakers and outlet bank load limits

Once the receptacle mix is confirmed, trace how the unit subdivides its input feed into protected branch circuits.

Under OSHA 1910.304(b)(4)(ii)(C), on a branch circuit supplying two or more receptacles or outlets, receptacle ratings shall conform to the values listed in Table S-5. In Table S-5, receptacle ratings are Not over 15 amperes for a 15 amperes circuit, 15 or 20 amperes for a 20 amperes circuit, and 30 amperes for a 30 amperes circuit.

For example, Vertiv Geist VP8881 has a 230/400V WYE 16A x 3 Phase input (11.0kW load capacity), no internal overcurrent protection, and a 3m 2.5mm² H07RN-F power cable with an IEC60309 16A IP44 plug.

All MPH2 Rack PDU units with input current rating of 30 A and higher feature 100% rated hydraulic-magnetic breakers, and for all UL-listed models, maximum cord and plug-connected loading is limited to 80% continuous loading. Low-profile circuit breakers are used on all MPH2 0-U Rack PDUs with two or three branch circuits; standard-profile circuit breakers are used on MPH2 horizontal models and on certain vertical models that have 6 branch circuits or have a 240 VAC rating. The MPH2 Rack PDU identifies the receptacles with numbers and groups them by branch with a letter referring to the proper circuit breaker. For MPH2 M and R models, the factory-default receptacle Overcurrent Warning Threshold is 90% and Overcurrent Alarm Threshold is 95%, calculated from the maximum receptacle current rating on the nameplate.

Comparing published single-phase and three-phase models illustrates four distinct branch breaker architectures:

• Asymmetric bank breakers on horizontal units: Eaton Tripp Lite PDU1230 is a single-phase 200; 208; 220; 230; 240 V Basic PDU recommended for 30A 200-240V service, agency de-rated to 24 A continuous maximum input amps. Tripp Lite PDU1230 has (16) C13 and (4) C19 receptacles (15A max per breakered C19 bank; 12A max per breakered C13 bank) protected by 1 - 10A breaker for the C13 bank and 1 - 15A breaker for the C19 bank.
• Dual equal breaker banks on vertical single-phase units: The Tripp Lite PDUV30HV uses a 0U metal chassis that distributes power across 38 outlets (32 C13 and 6 C19) arranged in two equal banks protected by 15A circuit breakers.
• Hydraulic-magnetic miniature circuit breakers on international single-phase units: On the Legrand 0U Rack PDU, each magnetic hydraulic MCB has a 16A rated current, 250 V rated voltage, 50/60 Hz frequency, 1 pole as standard (2 poles as CTO option), 3000 breaking capacity (Icn), and UL/CSA, VDE, CCC approvals.
• Six-branch two-pole breakers on three-phase units: Server Technology PRO2 Switched PDU C2W48CE-YQME2M66 meets UL and IEC 62368-1 branch circuit protection requirements through UL 489 rated magnetic-hydraulic circuit breakers or UL 248 fuses. The C2W48CE-YQME2M66 input is 208 V at 50/60 Hz via a 208V Wye 60A IEC 60309 3P+N+G 9Hr plug, with 60 A input current, 48 A rated input current, and 17.3 kW input power capacity. On the C2W48CE-YQME2M66, branch circuit protection consists of six (6) branch 2-pole, 20A trip circuit breakers compliant with UL 489, CSA C22.2 No. 5 and IEC/EN 60947-2, rated ≤ 16A with a 10 kAIC interrupt rating.

Internal breaker count can also cap the total power capacity of a universal chassis even when the input cable is identical. Vertiv Geist Facility Side Cable FSC3U002 (30/32A, 230/400V WYE) supports 11.0kW on a 3 Breaker UPDU vs 22.0kW on a 6 Breaker UPDU, where max kW is limited by internal UPDU circuit breakers. Similarly, across standard model families, for CE-Mark MPH2 models, single-phase input capacities are 3.7 kW (240 VAC, 16 A) and 7.3 kW (230 V, 32 A), and three-phase input capacities are 11 kW (230/400 V, 16 A) and 22 kW (230/400 V, 32 A). For UL-Listed MPH2 models, single-phase capacities are 1.4 kW (120 VAC, 12 A), 1.9 kW (120 VAC, 16 A), 2.9 kW (120 VAC, 24 A), and 4.9 kW (208 VAC, 24 A); three-phase capacities are 8.6 kW (120/208 VAC, 24 A), 14.4 kW (120/208 VAC, 40 A), and 17.3 kW (120/208 VAC 48 A; 240/415 VAC, 24 A).

In multi-node GPU racks, rack power distribution units (rPDUs) typically derive 200-240 VAC single phase power by dividing a three-phase input power circuit into three individual single-phase circuits. In NVIDIA DGX SuperPOD H100 deployments, the preferred power for high-density deployment patterns is 415 VAC, 32A, three-phase, N+1. For NVIDIA DGX H100 systems, four of the six power supplies must be energized for the system to operate, and a minimum of three power sources (rPDUs) each connecting to two of the six system power supplies guarantees four remain energized if one source fails. NVIDIA DGX SuperPOD guidance states to label all the power connections to indicate the source of power (PDU #) and the specific circuit breaker numbers used within each PDU. When mapping dual feeds or multi-source power zones, combine this breaker check with our redundant power supply feed mapping guide and rack power selection guide for GPU servers.

Check input cord gauge, terminal capacity, and cord retention

The third check separates the upstream input cable or hardwired terminal block from the downstream equipment jumper cords plugged into the receptacles.

On the upstream side, the Legrand 0U Rack PDU uses a 3m (9.84 ft) HO7RNF 3G6 input cable with an IEC 60309 32A 2P+E plug, rated 32A at 230V single-phase (200-240V) for 7.4kW at 230V. APC Basic Rack PDU AP7553 has a 200V, 208V, 230V input using 1 power cord (3.1 meters) with an IEC 60309 32 A 2P + E connection, 7400VA load capacity, and 32A maximum input current. On three-phase 16A units, Vertiv Geist VP8881 has a 230/400V WYE 16A x 3 Phase input (11.0kW load capacity), no internal overcurrent protection, and a 3m 2.5mm² H07RN-F power cable with an IEC60309 16A IP44 plug.

For hardwired installations and chassis grounding, Vertiv documents explicit conductor cross-sections and upstream breaker pairings. In Vertiv Liebert MPH2 Table 2-1, hard-wired MPH2 connection terminals accept solid conductors up to 6 mm² (≤32 A) or 16 mm² (>32 A), stranded conductors up to 4 mm² (≤32 A) or 10 mm² (>32 A), and maximum wire gauge 10 AWG (≤32 A) or 6 AWG (>32 A). In Vertiv Liebert MPH2 Table 2-3, ground-strap wire gauge by MPH2 rating is 14 AWG (12 A NA), 12 AWG or 4.0 mm2 (16 A), 10 AWG (24 A NA), 6.0 mm2 (32 A EU), and 6 AWG (40 A and 48 A NA). In Vertiv Liebert MPH2 Table 2-4, the rated current of the upstream circuit breaker for maximum input current per pole is 15 A (NA) for 12 A, 20 A (NA) or 16 A (EU, WW) for 16 A, 30 A (NA) for 24 A, 32 A (EU, WW) for 32 A, 50 A (NA) for 40 A, 60 A (NA) for 48 A, and 63 A (EU, WW) for 63 A.

On the downstream equipment cord side, the SCHURTER rewireable C13 connector according to IEC 60320-1 is rated 10 A / 250 VAC at 50 Hz (IEC) and 15 A / 250 VAC at 60 Hz (UL/CSA per UL 60320-1 and CSA C22.2 no. 60320-1). SCHURTER rewireable C13 connector variants 3-122-694 (8.5 mm cable diameter) and 3-122-695 (10 mm cable diameter) accept max wire size 3 x 1 mm² (IEC) / 3 x 18 AWG (UL) and 3 x 1.5 mm² (IEC) / 3 x 14 AWG (UL), respectively.

Workplace electrical rules also govern how flexible cords are marked, supported, and strain-relieved inside the rack environment. Under OSHA 1910.305(a)(2)(xi), cable assemblies and flexible cords and cables shall be supported in place at intervals that ensure that they will be protected from physical damage. Under 1910.305(g)(2)(i), specified flexible cords and cables shall be durably marked on the surface at intervals not exceeding 610 mm (24 in.) with the type designation, size, and number of conductors. Under 1910.305(g)(2)(ii), flexible cords may be used only in continuous lengths without splice or tap, and only hard-service or junior hard-service cord No. 14 and larger may be repaired if spliced. Under 1910.305(g)(2)(iii), flexible cords and cables shall be connected to devices and fittings so that strain relief is provided that will prevent pull from being directly transmitted to joints or terminal screws.

Prepare the nameplate, input feed, and breaker diagram for an RFQ

Before submitting a rack power bill of materials or requesting a pre-shipment check, compile three engineering artifacts so the quoted unit and cord bundle match your cabinet layout:

1. Attach the nameplate or specification sheet. Include the nominal input voltage, phase configuration, maximum and agency-derated input current, and total power capacity.
2. Specify the input cord and upstream feed parameters. Record the input plug standard, cord length, input cable conductor cross-section or hardwired terminal gauge, and the upstream panel breaker rating.
3. Provide the branch circuit breaker and outlet bank diagram. List the exact receptacle count per bank, the trip rating and continuous limit of each branch breaker, and how server and switch power supplies are distributed across the banks.
4. Match downstream jumper cord gauges and retention latches. Pair each outlet bank with the required jumper cord conductor size, jacket marking, routed length, and mechanical cord-locking clip style.
5. Submit the package for quoting and inspection. We quote rack PDUs and matched C13/C14 and C19/C20 jumper bundles with complete assembly specifications and pre-shipment inspection records. Send your completed specification through the rack power RFQ checklist or bundle the unit and matching jumper cords through the rack power accessory kit.

Sources

• U.S. Occupational Safety and Health Administration — Wiring Design and Protection Standard
• U.S. Occupational Safety and Health Administration — Wiring Methods, Components, and Equipment for General Use Standard
• SCHURTER AG — IEC Appliance Outlet F Technical Datasheet
• SCHURTER AG — IEC Appliance Outlet J Technical Datasheet
• SCHURTER AG — Rewireable IEC Appliance Connector Technical Datasheet
• NVIDIA — DGX SuperPOD Data Center Design Guide
• Legrand — Vertical Rack PDU Technical Data Sheet
• Vertiv — Liebert Rack PDU Installer and User Manual
• Vertiv — Geist Monitored Rack PDU Specification Sheet
• Vertiv — Geist Rack PDU Family Overview and Model Guide
• Server Technology — Switched Rack PDU Specification Sheet
• Tripp Lite by Eaton — Single-Phase Basic Rack PDU Specification Sheet
• Tripp Lite by Eaton — Vertical Basic Rack PDU Submittal Drawing
• APC by Schneider Electric — Basic Zero-U Rack PDU Specification Sheet