Why a Military PDU Specification Deserves Its Own Effort
Knowing how to specify a military PDU separates a clean procurement from a long argument at acceptance. The specification tells suppliers, in one document, what the power distribution unit must do. Written well, every supplier prices the same thing and acceptance criteria are fixed before the order. Written badly, it is one line — "MIL-STD compliant, 10-output, rack-mount PDU" — that every supplier reads differently.
This article builds a rugged power distribution unit specification item by item. Vehicle DC distribution questions are covered in our military vehicle electrical architecture guide, and automatic source transfer and remote monitoring in our military PDU guide. Here the focus is the requirement sentence and how to verify it.
Before You Write: Platform, Sources and Load List
The first page of the specification rests on three inputs:
- Platform and installation: a 19-inch shelter cabinet, an armoured vehicle hull, an outdoor military power distribution box on a mast or wall, or a ship's equipment room. Location drives every mechanical, environmental and EMI requirement.
- Sources: mains, generator, UPS, batteries, alternator, charger — each with voltage, frequency and availability.
- Load list: voltage, continuous and inrush current, criticality and operating modes for every consumer.
Without a load list, the supplier guesses or offers its largest enclosure.
The 12-Point Checklist
1. Input Sources and Source Transfer
State the number of sources, voltage and frequency range, number of phases and priority order. Is transfer automatic or manual? If automatic, what triggers it, and how long an interruption can the load tolerate during transfer? If no-break supply is required, say whether the PDU or an upstream UPS provides it.
2. Output Count, Voltage and Current
Give the output count including spares, and voltage (AC or DC), continuous and inrush current per channel. Write total current separately and say whether it assumes every channel at full load or a diversity factor; otherwise two suppliers propose two different units.
3. Protection: Breakers, Fuses, Reverse Connection
Require overcurrent and short-circuit protection on every output; specify breaker or fuse, field replaceability and the number of spare fuses. Input over/undervoltage, surge protection and, on DC systems, reversed-battery protection are separate requirements. Reverse-connection protection can also sit in a dedicated unit such as the TPB-01 reverse polarity protection unit; then state the responsibility boundary.
4. Switching, Emergency Stop and Bypass
Are outputs switched individually, in groups or in sequence? State which contactors the emergency stop opens and, if there is a bypass switch, which protections it overrides. A bypass keeps power flowing but also silences protection, so its use belongs in the operating documentation.
5. Communication and Remote Monitoring
List the interface (Ethernet, RS-422, CAN), protocol or software, monitored values (voltage, current, frequency, temperature) and remote actions (output on/off, restart). For logging, state the record count and logged values.
6. Mechanical: Rack Units, Dimensions, Weight, Mounting
For a rack unit, give U height, maximum depth and rails; for a vehicle or outdoor unit, the envelope, mounting hole pattern and door direction. Maximum weight and maintenance access are the items most often forgotten.
7. Environmental Conditions
State operating and storage temperature, humidity (condensing or non-condensing), and dust and water protection. If you require an IP rating, define both digits as explained in our IP ratings guide. For vibration, shock and rain, give the MIL-STD-810 revision and method number; "MIL-STD-810 compliant" on its own is not a requirement.
8. EMI/EMC and Power Quality
A PDU shares the cabinet with radar and radios. Choose the MIL-STD-461 revision and the test items you need (for example CE102, CS101, RE102, RS103). On 28 VDC vehicles, state the MIL-STD-1275 revision for input power quality. What each standard actually measures is explained in our MIL-STD-461 and MIL-STD-810 guide.
9. Connectors and Cable Entries
Specify the connector family (for example MIL-DTL-38999), pin assignment ownership, keying against mismating and the cable gland protection class. If the integrator selects connectors, tie this item to the Interface Control Document (ICD).
10. Built-In Test, Fault Indication and Logging
Define the detected faults (over/undervoltage, overtemperature, breaker trip), their indication (LED, alarm, remote message) and the output's behaviour: switch off, or warn and keep running?
11. Verification and Documentation
Put a verification method next to every requirement. Request before delivery: ICD, electrical or block diagram, test plan and procedure, acceptance test report and certificate of conformity. For a test report to a standard, give standard, revision and method number.
12. Delivery, Spares and Warranty
Operation and maintenance manual, spare parts list (fuses, breakers, fans, gaskets), training, and warranty period and scope.
How to Write a Requirement Sentence
Each item should contain one measurable request. Compare:
- Weak: "The PDU shall have a sufficient number of protected outputs and be suitable for harsh environments."
- Strong: "The PDU shall provide at least 10 outputs, each with its own overcurrent and short-circuit protection; each output shall carry 25 A continuously."
The second has a number, a unit and a condition, so it can be verified. Verification uses four methods:
| Method | When? | Example |
|---|---|---|
| Test | Requirements that need measurement | Channel current, source transfer, EMI emission |
| Analysis | When testing is costly or destructive | Thermal calculation, total current budget |
| Inspection | Visual or dimensional checks | Dimensions, labelling, connector type |
| Demonstration | When seeing the function work is enough | Remote output switch-off, emergency stop |
This is also where "designed to" and "tested to" separate: for an item marked "verification: test" you ask the supplier for a report; for an item marked "analysis" a calculation document is enough.
Specification Summary Table
Use this as the skeleton of a rugged PDU specification:
| No | Item | What to write | Verification |
|---|---|---|---|
| 1 | Sources | Number, voltage, frequency, priority, transfer type | Test |
| 2 | Outputs | Channel count, voltage, channel and total current | Test |
| 3 | Protection | Breaker/fuse, input protection, spares | Test + inspection |
| 4 | Switching | Group/sequential switching, emergency stop, bypass | Demonstration |
| 5 | Communication | Interface, monitored values, log | Demonstration |
| 6 | Mechanical | U / envelope, weight, mounting | Inspection |
| 7 | Environmental | Temperature, humidity, IP, MIL-STD-810 methods | Test or analysis |
| 8 | EMI and power quality | MIL-STD-461 items, MIL-STD-1275 | Test |
| 9 | Connectors | Family, pin assignment, keying | Inspection |
| 10 | Built-in test | Detected faults, indication, output behaviour | Demonstration |
| 11 | Documents | ICD, diagrams, test plan and reports | Inspection |
| 12 | Delivery | Manuals, spares, warranty | Inspection |
Reading the Checklist Against TEDEG PDUs
Reading the same list against a datasheet makes gaps easy to spot. The four products in our military power distribution units category answer different items in different ways:
| Item | PDU-RT5002 | PDU-R2D4 | TDG-EDP-D0X | MAR-2 |
|---|---|---|---|---|
| Sources | 3 × 220 VAC 50 Hz; mains → generator, automatic | 180–240 VAC 50 Hz; mains + UPS | 4 DC inputs; 400 A busbar | 220 VAC 50 Hz; manual mains / generator |
| Outputs | 10 × 25 A AC/DC | 8 AC + 2 DC | MIDI-fused, 30 / 60 / 100 A @28 VDC | 9 × 220 VAC, fused |
| Communication | Ethernet, last 100 records | Ethernet 100 Mbps + RS-422 | — | LED indicators |
| Mechanical | 4U 19-inch | 2U 19-inch, ≤ 10 kg | Aluminium enclosure, 14 ± 2 kg | Panel with rain roof, 14 ± 1 kg |
The PDU-RT5002 switches its output off on a fault and sounds an audible alert; with bypass active, faults and warnings are ignored. Its datasheet lists the MIL-STD-461F items — CE102, CS101, CS114–CS116, RE102, RS103 — and MIL-STD-810G coverage across 11 methods: the detail item 8 asks for. The PowerGuard PDU-R2D4 switches outputs individually, in groups or in sequence; it has a surge arrester on the input, emergency stop and bypass on the front panel, and operates at −30 °C … +50 °C.
The military vehicle DC power distribution unit (TDG-EDP-D0X) shows what item 4 looks like in a vehicle, with threshold values: the input contactor opens below 21 VDC and closes above 21.5 VDC, and every threshold except the control unit's switch-on voltages is adjustable. Its watertightness is defined to MIL-STD-810G Method 506.5 Procedure I (30 minutes). The PowerGuard MAR-2 gives every output its own neutral and earth terminal and works outdoors with K1 / K2 contactors and a guarded emergency stop.
Military PDU Manufacturer in Turkey: TEDEG Defence
TEDEG Defence is an Ankara-based defence company that designs and manufactures rack-mount, vehicle and outdoor power distribution products.
| Profile | Details |
|---|---|
| Company | TEDEG Defence Industry A.Ş. |
| Headquarters | Ankara, Turkey |
| Founded | 2023 |
| Registrations and certificates | ISO 9001, EYDEP |
| Cluster memberships | OSSA, SAHA Istanbul |
On the PDU-RT5002, channel count, voltage level and connector type are offered as customer configurations; on the PDU-R2D4, output voltage and current are set per project.
Frequently Asked Questions
Which standards belong in a military PDU specification?
Usually MIL-STD-461 for EMI/EMC, MIL-STD-810 for environment and, on 28 VDC ground vehicles, MIL-STD-1275 for input power quality — each with revision letter and test items or method numbers.
How do I tell "designed to" from "tested to" in a specification?
Write the verification method next to every requirement: "test" calls for a report, "analysis" for a calculation. An item-by-item compliance matrix at quotation stage makes the difference visible.
Do I need a full specification to request a quotation?
No. Sources, output count and channel current, installation, communication interface and operating temperature are enough for a first quotation; the detail can follow during technical clarification.
Should the specification describe a rack PDU, a vehicle DC unit or an outdoor panel?
Describe the installation and sources; the type follows. AC sources in a shelter cabinet mean a rack unit, a 28 VDC vehicle a busbar-based DC unit, and field mains or generator distribution an outdoor panel.
Conclusion
A good military PDU specification carries a measurable value and a verification method in each of its 12 items. Start with the platform, the sources and the load list; then fill in the items and request the documents up front.
Send your specification or load list through the quote form and our engineering team will answer it item by item against the product datasheets. Field example: tactical truck power architecture modernisation.