単相式と多相式のポータブル接地セット：購入者はどちらの構成を選ぶべきか？

We often receive inquiries asking whether a three-phase network always requires one integrated three-phase portable earthing set.

The answer depends on the approved earthing and short-circuiting arrangement.

Some projects use separate single-phase devices for individual conductors. Other projects use a multi-phase assembly with several line clamps, short-circuiting cables, a connecting cluster, and a common earth lead.

The correct configuration depends on the required phase bonding, connection points, phase spacing, cable distances, fault-current duty, access conditions, handling limits, and test evidence. The number of phases in the power system alone is not enough to make the decision.

現地の規制および現場の安全手順に従ってください。

Quick Answer: Choose the Approved Arrangement, Not Just the Phase Count

In portable earthing equipment, “single-phase” and “multi-phase” describe equipment configurations. They do not simply describe whether the electrical network supplies single-phase or three-phase power.

A single-phase device normally provides an individual connection path for one conductor or phase within an approved work arrangement.

A multi-phase set connects two or more phases as one controlled assembly. In a typical three-phase system, this may be sold as a three-phase portable earthing set.

Neither configuration is automatically better.

購入者は以下の点を確認する必要があります:

• How many conductors must be connected
• Whether phase-to-phase short-circuiting is required
• Whether each phase needs an individual earth connection
• 位相間隔
• Distance to the earth point
• Clamp interfaces
• Cable arrangement
• Fault-current rating
• Handling and storage limits
• テストレポートの範囲

IEC 61230 shows both single-phase and multi-phase equipment configurations. Its examples include line clamps, earthing cables, short-circuiting cables, earth clamps, and connecting clusters. The standard also notes that its connection diagrams are examples and are not suitable for every situation.

What “Single-Phase” Means in Portable Earthing Equipment

The term “single-phase equipment” can be misunderstood.

In this context, it does not necessarily mean that the product is intended only for a residential single-phase circuit or a low-voltage single-phase network.

It normally describes an individual device or lead arrangement connected to one conductor or phase position. Depending on the approved system, the device may include:

• One line clamp
• One flexible earthing cable
• One earth clamp
• Ferrules or end fittings
• An operating interface
• A fixed or detachable insulating component where required

Several separate single-phase devices may be specified for work on a multi-phase installation. However, they should not be combined casually in the field.

The project engineer should define:

• How many devices are required
• Which conductors they connect
• Whether they are used independently
• Whether phase-to-phase bonding is also required
• Whether they must have identical ratings and dimensions
• How the complete arrangement is controlled and identified

Single-phase equipment describes the configuration of the portable device. It does not, by itself, define the network voltage, application, or approved work method.

What “Multi-Phase” or “Three-Phase” Means

Multi-phase equipment connects more than one phase or conductor as part of one controlled assembly.

一般的な構成には以下が含まれる場合があります。

• Two or more line clamps
• Phase-to-phase short-circuiting cables
• A connecting cluster
• 支店長
• One or more earthing cables
• An earth clamp
• フェルールとエンドフィッティング
• A controlled assembly drawing
• One kit-level identification system

In a three-phase AC installation, this arrangement is often described commercially as:

• Three-phase earthing set
• Three-phase short-circuiting set
• Three-phase and one-earth set
• 3-phase 1-earth grounding set
• Trifurcating earthing set
• Cluster-type portable earthing set

These names should not replace a technical drawing.

Two suppliers may both quote a “three-phase set” while offering different:

• 支店の配置
• ケーブルの長さ
• Cluster designs
• Number of earth leads
• クランプモデル
• Cable cross-sections
• Fault-current ratings
• テスト証拠

The quotation should therefore show the complete proposed configuration.

Single-Phase vs Multi-Phase Portable Earthing Sets

These are procurement and configuration differences. They are not a universal safety ranking.

When Individual Single-Phase Devices May Be Suitable

Separate single-phase devices may be considered when the approved project arrangement requires independently positioned leads.

They may also be practical where:

• Phase connection points are widely separated
• Distances differ significantly between conductors
• Each phase uses a different connection position
• Different clamp models are required
• One large cluster would be difficult to position
• Equipment must be transported in smaller individual sections
• Modular inspection and replacement are important
• The approved work procedure specifies individual devices

This arrangement can provide more flexibility in lead length and clamp selection.

However, flexibility creates additional asset-control requirements.

The buyer may need to manage:

• Several separate serial numbers
• Multiple inspection records
• Individual storage positions
• Separate cable-length records
• Clamp-model consistency
• Rating consistency
• Replacement-device approval
• Prevention of components being mixed between kits

A group of loose leads should not be treated as one approved set merely because the cable sizes and colors look similar.

Each device should be identifiable and connected to the correct technical documents.

When an Integrated Multi-Phase Set May Be Suitable

An integrated multi-phase set may suit projects that require controlled phase-to-phase short-circuiting within one assembly.

It may be considered where:

• The approved arrangement requires several phases to be bonded
• Phase spacing is known and reasonably consistent
• A connecting cluster is part of the approved design
• Branch-lead lengths can be defined before production
• One kit-level asset identity is preferred
• The full assembly can be handled within site limits
• The storage case can keep all components together
• Test evidence covers the complete multi-phase configuration

An integrated set can make it easier to control the complete supply scope. Missing components may also be easier to identify when every branch, clamp, and earth lead has an assigned place.

However, the arrangement may be less adaptable when:

• Phase spacing changes between sites
• Earth-point positions vary
• Several clamp interfaces are used
• Cabinet access is restricted
• One branch requires a different length
• The connecting cluster is difficult to position
• The complete assembly is too heavy for the approved handling method

One damaged branch or termination may also affect the service status of the complete set.

The buyer should define how component replacement, repair, and re-approval will be managed.

The Approved Work Arrangement Comes First

The equipment supplier should not decide the earthing arrangement from the network description alone.

For example, the following request is incomplete:

Three-phase portable earthing kit for an 11 kV system.

It does not tell us:

• Whether all three phases must be short-circuited together
• Whether individual phase-to-earth devices are required
• Whether a common cluster is allowed
• How many earth points are available
• Whether the neutral is included
• Whether a short-circuiting bar is specified
• What the phase spacing is
• Where the earth point is located
• Which connection interfaces are used
• What fault-current duty applies

The approved work arrangement should come from the project engineer, utility requirement, site procedure, or tender specification.

The supplier can then prepare a matching assembly proposal.

私たちのガイド 携帯型接地キット入札のためのエンジニアリング入力 explains how these requirements should be transferred into an RFQ and technical data schedule.

Phase Spacing and Earth-Point Distance

Physical layout is one of the main factors separating individual and integrated configurations.

購入者は以下を提供する必要があります。

• Distance between phase connection points
• Distance from each phase to the earth point
• Horizontal and vertical offsets
• 機器の操作方法
• Available cable route
• Cabinet or structure dimensions
• Barriers and access restrictions
• Required branch-lead lengths
• Required earth-lead length

An integrated set is especially sensitive to these dimensions.

If branch leads are too short, the assembly may not reach the required points. If they are unnecessarily long, the extra cable can increase weight, slack, storage requirements, and handling difficulty.

Individual single-phase devices also require controlled lengths. “Longer” does not automatically mean “more suitable.”

Cable length should match the approved connection route and equipment arrangement.

For more information, review our guide to 携帯用アースリードの選択要因.

Clamp Interfaces May Change the Best Configuration

Each connection point should be reviewed before choosing the lead arrangement.

Possible interfaces include:

• 丸型導体
• フラットバスバー
• Tubular busbars
• Ball studs
• Fixed earthing points
• Earth bars
• 接地棒
• Switchgear terminals

In some installations, all three phases use the same interface.

その他:

• One phase may have restricted access
• Different clamp orientations may be required
• The earth point may use a different clamp material
• One conductor may require an adapter
• Several operating-pole heads may be needed

Separate single-phase devices may offer more flexibility when different clamps or lead lengths are required.

A multi-phase set can also use different clamp models, but the mixed configuration should be included in the assembly drawing and test-evidence review.

現場の声を力強いメッセージへ。 grounding clamp interface guide explains what dimensions, materials, access details, and drawings buyers should provide.

Fault-Current Rating Must Match the Actual Arrangement

Both single-phase and multi-phase equipment must match the engineer-approved fault-current duty.

購入者は以下の点を確認する必要があります。

• 定格電流
• 定格時間
• Peak-current requirement
• ケーブル断面
• ケーブルの長さ
• クランプモデル
• Ferrules and terminations
• リード数
• Connecting cluster
• Complete test configuration

The same cable cross-section does not prove that two different arrangements have the same verified rating.

For a multi-phase set, the evidence should account for the relevant:

• 支店長
• クラスター接続
• 位相クランプ
• Earth lead
• アースクランプ
• フェルール
• Complete assembly geometry

For separate single-phase devices, the buyer should confirm whether each device has appropriate evidence and whether their combined use follows the approved project arrangement.

The configuration should not be selected from system voltage alone.

私たちのガイド portable earthing kit fault-current ratings explains how buyers should review kA, rated time, peak factor, and complete assembly evidence.

Handling, Weight, and Storage

The most technically suitable configuration must also be manageable under the approved site procedure.

Individual devices may reduce the weight of each item. However, the complete group may require more bags, labels, and inspection records.

An integrated set may simplify kit-level control. However, its combined cables, clamps, and cluster may be heavier and less flexible.

Buyers should request actual product weights and packing dimensions rather than relying on general assumptions.

Inspection, Maintenance, and Component Replacement

Configuration choice affects the equipment-management system after delivery.

Individual single-phase devices

購入者は以下を決定する必要があります。

• Whether every device has its own serial number
• Whether several devices share one kit number
• Whether leads from different kits can be mixed
• How cable length is recorded
• How replacement clamps are approved
• How inspection status is shown
• How incomplete groups are quarantined

Integrated multi-phase sets

購入者は以下を決定する必要があります。

• Whether branch leads have individual identification
• Whether the connecting cluster has its own serial number
• Whether one branch can be replaced separately
• Whether replacement requires a revised drawing
• Whether the replacement preserves the tested design
• Whether the complete kit must be removed from service after component damage
• How repairs are documented

Replaceability should not be confused with interchangeability.

A replacement component may fit physically but still differ in:

• ケーブル長
• 断面
• クランプモデル
• フェルール設計
• 材料
• 評価
• テスト証拠の範囲

Component changes should follow the approved inspection, repair, and configuration-control process.

Test Evidence Must Match the Offered Configuration

The test report should show what equipment arrangement was tested.

購入者は以下の点を確認する必要があります:

• Single-phase or multi-phase configuration
• Number of line clamps
• Number of earth clamps
• ケーブルの数
• ケーブル断面
• ケーブルの長さ
• リードアレンジメント
• Connecting cluster
• フェルールとエンドフィッティング
• クランプモデル
• 定格電流
• 定格時間
• ピーク電流基準
• Assembly drawing number
• 適用規格
• テスト結果

IEC 61230 covers portable equipment used for temporary earthing or earthing and short-circuiting on isolated or de-energized AC and DC installations, including overhead and underground networks. Its scope includes complete equipment and certain separate components, while relevant working procedures remain outside the standard.

A report title stating “IEC 61230 portable earthing equipment” does not automatically prove every single-phase and multi-phase configuration offered by the supplier.

The buyer should be able to connect:

Test report → tested drawing → supplier quotation → production drawing → product marking

Single-Phase vs Multi-Phase Decision Checklist

No single answer should decide the configuration by itself.

The final choice should follow the combined technical and operational requirements.

見積もり前に購入者が提供すべきもの

A useful RFQ should include the following information.

A request stating only “three-phase grounding set” does not provide enough information for a reliable quotation.

サプライヤーが返品すべきもの

The supplier should return:

• 提案された構成
• 組立図
• Number of line clamps
• Number of earth clamps
• Phase-lead arrangement
• Short-circuiting lead arrangement
• Connecting-cluster details
• ケーブル断面
• 実際のケーブル長
• クランプモデル
• Ferrule and termination details
• Operating-pole interfaces
• 完全なアセンブリ定格
• 試験報告書参照
• Marking proposal
• Kit and component identification
• 梱包計画
• Spare-component list
• 技術的な逸脱

The buyer should compare these items before comparing price.

よくある購入者のミス

Assuming Every Three-Phase Network Needs One Integrated Set

The network phase count does not automatically determine the portable equipment configuration.

The approved work arrangement comes first.

Treating Single-Phase Equipment as Low-Voltage Equipment

“Single-phase” describes the equipment configuration in this context. It does not automatically limit the product to a low-voltage single-phase supply.

Choosing by the Number of Components

More components do not automatically provide more flexibility or protection. Fewer components do not automatically make a set easier to control.

The configuration must match the work point.

Ignoring Phase Spacing

Fixed branch-lead lengths may not fit the actual installation.

Provide measured distances and drawings before production.

Comparing Cable Cross-Section Only

Cable size is only one parameter.

Buyers should also compare clamps, lengths, terminations, clusters, ratings, and test evidence.

Mixing Independent Devices from Different Kits

The devices may have different lengths, ratings, clamps, production batches, or inspection status.

Configuration control should prevent unintended mixing.

Replacing a Branch Without Reviewing the Complete Assembly

A physically similar branch may not match the tested drawing or approved kit rating.

Accepting a Report Without an Assembly Drawing

Without the drawing, the buyer may not know whether the evidence covers an individual device or an integrated multi-phase arrangement.

Selecting the Configuration from a Product Photograph

A photograph cannot confirm phase spacing, lead lengths, ratings, terminations, or test scope.

How We Review a Configuration Inquiry

When we receive an inquiry, we review the configuration in a fixed order.

We Confirm the Approved Work Arrangement

We ask whether the phases must be earthed individually or connected through a multi-phase short-circuiting arrangement.

We Identify the Number of Connection Points

We confirm the number of phases, conductors, earth points, and any neutral connection.

We Review Phase Spacing and Earth Distance

We request measurements, photographs, and drawings.

We Check the Clamp Interfaces

We identify the conductor, busbar, stud, earth bar, or other connection point for every lead.

We Compare Individual and Integrated Layouts

We review lead lengths, cluster position, handling, and access.

We Confirm the Fault-Current Duty

We ask for the engineer-approved rated current, time, and peak requirement.

We Review the Tested Configuration

We compare the proposed drawing with available test evidence.

We Confirm Identification and Storage

We define kit IDs, component labels, bags, cases, and inspection records.

We Declare Technical Deviations

Any difference from the tender or tested design should be identified before production.

This process is more reliable than choosing a configuration from the terms “single-phase” or “three-phase” alone.

FAQ

Does a three-phase network always require a three-phase portable earthing set?

No. The required configuration depends on the approved earthing and short-circuiting arrangement, connection points, phase spacing, fault duty, and site procedure.

What does single-phase portable earthing equipment mean?

It normally describes an individual device or lead arrangement serving one conductor or phase connection. It does not simply mean equipment for a single-phase electrical supply.

Can three single-phase devices replace one multi-phase set?

Only when the project engineer and approved procedure permit that arrangement. The ratings, interfaces, cable lengths, identification, and test evidence must also support it.

Is an integrated multi-phase set easier to manage?

It may be easier to control under one kit ID and storage case. However, it may also be heavier and more dependent on fixed phase spacing and branch lengths.

Which configuration is easier to repair?

Individual devices may allow modular replacement. An integrated set may require a more detailed configuration review. In both cases, replacement parts must match the approved rating and design.

Does the test report need to show the lead arrangement?

Yes. Buyers should be able to identify the number of leads, cable sizes, cable lengths, clamps, terminations, connecting cluster, rating, and drawing reference.

Can different clamp models be used in one multi-phase set?

They may be used when required by the actual interfaces, but the complete mixed configuration should be technically reviewed and supported by suitable evidence.

Should every lead have its own serial number?

That depends on the project’s asset-management system. Buyers may use one kit ID, individual component IDs, or both.

見積もり依頼を受ける前に、購入者はどのような情報を提供すべきでしょうか？

Provide the approved arrangement, application, number of phases, phase spacing, earth distance, interfaces, fault duty, cable requirements, operating method, documents, marking, and storage requirements.

実用的な購入者向け要約

Single-phase and multi-phase describe portable earthing equipment configurations. They do not simply describe the phase count of the electrical network.

Individual single-phase devices may offer more flexibility where connection distances, clamp interfaces, or work positions vary.

An integrated multi-phase set may provide a controlled phase-bonding arrangement where spacing, branch lengths, and cluster position are clearly defined.

Neither configuration is universally better.

Before selecting, confirm:

• Approved earthing arrangement
• Number of phases or conductors
• Phase-to-phase bonding requirement
• 位相間隔
• Earth-point distance
• Clamp interfaces
• ケーブルの長さ
• Fault-current duty
• 操作方法
• 取扱い及び保管上の注意
• 交換制御
• テスト証拠
• マーキングとトレーサビリティ

The best configuration is the one that matches the approved work method, actual connection geometry, complete assembly rating, and controlled test evidence.

For product sourcing after the technical configuration has been approved, buyers can review our 携帯型接地・短絡対策キット.

現地の規制および現場の安全手順に従ってください。