PDB most often stands for Power Distribution Board in electrical drawings, panel schedules, and building-services documents. However, PDB can also mean Power Distribution Block in a component catalogue or bill of materials. Some suppliers use Power Distribution Box as well. The document legend and equipment context determine the correct expansion.
| Where you see “PDB” | 最も可能性の高い意味 | 電気的安全におけるそれぞれの役割を明確にするための、漏れ電流、残留電流、および地絡電流の包括的な比較。 | Best clue |
|---|---|---|---|
| Single-line diagram, load schedule, room layout, or feeder schedule | 配電盤 | An assembly that receives a supply and distributes it through protected outgoing circuits | It has an incomer, busbars, protective devices, and multiple feeders |
| Component catalogue, control-panel BOM, terminal schedule, or part number | 配電ブロック | A connection component that splits one or more incoming conductors into several outgoing conductors | It is specified by poles, conductor range, current, voltage, terminals, and mounting method |
| Vendor description or project shorthand | 配電ボックス | Usually an enclosed distribution assembly | The usage varies; verify the drawing legend and specification |
The important distinction is not the wording alone. A board or box is an assembly; a block is a component installed inside an assembly or enclosure.
PDB as Power Distribution Board
In building electrical systems and low-voltage distribution documents, 配電盤 is normally the intended meaning. The board accepts an incoming electrical supply and routes it to multiple outgoing circuits through switching and protective devices.
A typical distribution board may contain:
- an incomer or main switching device;
- busbars for phase, neutral, and protective conductors as applicable;
- miniature circuit breakers (MCBs), molded case circuit breakers (MCCBs), residual-current devices, fuses, or other protective devices;
- outgoing terminals and circuit identification;
- an enclosure that restricts access to live parts.
A distribution board does not inherently step voltage up or down. If the system voltage changes, a transformer, converter, or power-electronic supply performs that function. The PDB distributes power at the voltage presented to its incoming terminals, subject to its ratings and design.
The exact standard category depends on the assembly and market. For example, IEC 61439-3:2024 defines specific requirements for distribution boards intended to be operated by ordinary persons (DBOs) within its stated scope. It does not mean every industrial board called a PDB falls under Part 3.
For the general term without the “power” prefix, see 電気におけるDBの正式名称. For construction and specification factors, use the separate ディストリビューション・ボックスとセレクション・ガイド.
PDB as Power Distribution Block
In control-panel component catalogues and bills of materials, PDB can mean Power Distribution Block. This is not a complete board. It is a conductive connection device used to split an incoming conductor or power path into multiple outgoing connections.
Manufacturer literature demonstrates this usage directly. Mersen, for example, labels its MPDB range as a Power Distribution Block (PDB) and describes the blocks as a way to splice cables or split primary power into secondary circuits.
Do not assume the block provides branch-circuit overcurrent protection. Its function is connection and distribution unless the documented product includes another function. The surrounding design must address conductor ampacity, overcurrent protection, short-circuit current rating (SCCR), insulation, spacing, covers, mounting, and applicable panel requirements.
If the document lists conductor sizes, terminal openings, pole count, tightening torque, or DIN-rail/panel mounting beside “PDB,” it probably refers to the component. Read the complete Power Distribution Block guide before selecting one, or review VIOX 配電ブロック when the project has reached the product-evaluation stage.
Does PDB Mean Power Distribution Box?
It can. 配電ボックス appears in supplier descriptions and project terminology, especially when the equipment is enclosed or portable. However, “box,” “board,” “panelboard,” “load center,” and “consumer unit” are not automatically interchangeable technical classifications.
If a specification says “PDB box,” treat the phrase as a project label until the following are confirmed:
- assembly standard and market;
- rated voltage, current, frequency, and number of phases;
- incoming and outgoing protective devices;
- enclosure and environmental rating;
- intended operator and installation location.
How to Interpret PDB on a Drawing or BOM
Use this five-step check instead of guessing from the acronym:
- Read the legend. Project drawings often define PDB and other abbreviations explicitly.
- Check the document type. A feeder schedule points toward a board; a component BOM points toward a block.
- Inspect the neighboring labels. Incomer, feeder, bus coupler, and outgoing circuit suggest an assembly. Wire range, terminal count, pole, and torque suggest a component.
- Look for an equipment tag or part number. A tag such as PDB-1 may identify a board, while a manufacturer part number should lead to a component datasheet.
- Verify the governing specification. The project specification and manufacturer documentation override informal acronym usage.
This method matters in procurement. Ordering a distribution block when the drawing calls for an assembled distribution board is not a minor naming error; it changes the entire scope of supply.
PDB Compared with Related Electrical Abbreviations
| 略語 | Common expansion | Practical distinction |
|---|---|---|
| 配電盤（DB） | 配電盤 | General board abbreviation; often used without the word “power” |
| PDB | Power Distribution Board / Power Distribution Block | Context-dependent; identify whether the item is an assembly or component |
| 主配電盤 (MDB) | 主配電盤 | Main board at a defined level of the distribution hierarchy |
| SMDB | Sub-Main Distribution Board | Intermediate board supplied from an upstream main board |
| PDP | Power Distribution Panel | Project- or market-dependent term for a distribution panel |
| PDU | Power Distribution Unit | A distinct equipment category whose construction varies by application, such as IT racks or industrial systems |
These abbreviations describe project roles, not universal product classes. Always reconcile the abbreviation with the single-line diagram, equipment schedule, and technical specification. VIOX maintains a broader 電気用語の正式名称リファレンス for adjacent terms.
よくある質問
What is the full form of PDB in electrical engineering?
PDB most commonly means 配電盤 in building and power-distribution documents. In component catalogues and control-panel BOMs, it may mean 配電ブロック.
Are PDB and DB the same?
When PDB means Power Distribution Board, PDB and DB may identify the same general kind of assembly. A project may also use PDB for a particular power board while reserving DB for another distribution-board category, so the drawing legend controls the answer.
Is a power distribution block a circuit breaker?
No. A power distribution block primarily provides conductor connection and power splitting. It should not be treated as a circuit breaker or fuse unless the documented device specifically integrates a protective function.