10kV surge arrester selection should begin with the power system, not with the “10kV” label alone. Buyers must confirm the nominal system voltage, grounding method, maximum continuous operating voltage, temporary overvoltage conditions, protected equipment, installation environment, and mounting interface. A model may appear suitable by voltage class yet still have the wrong continuous operating capability, protection characteristics, housing, terminals, or dimensions for the project.
Before selecting a 10kV zinc oxide surge arrester, confirm:
- The system voltage, frequency, grounding method, and temporary overvoltage conditions.
- The required arrester ratings and the equipment being protected.
- The indoor or outdoor environment, mounting arrangement, dimensions, and project documents.
Start With the Actual 10kV Power System
A zinc oxide surge arrester is a protective device that limits transient overvoltage and directs surge current toward earth. Its metal oxide elements become conductive when the applied voltage rises above their normal operating condition. After the surge, the arrester returns to its normal high-resistance state.
The phrase “10kV system” identifies a nominal system class. It does not mean that the correct arrester must have a 10kV rated voltage.
LEEYD’s currently listed 10kV models, for example, have an arrester rated voltage of 17kV and a maximum continuous operating voltage of 13.6kV. These values describe different characteristics and should not be replaced by the nominal system voltage.
Confirm Nominal Voltage and Frequency
State the nominal system voltage and frequency shown in the project documents. Also confirm whether the stated voltage is phase-to-phase or phase-to-earth.
Ambiguous voltage information can lead to an incorrect comparison between the system and the arrester rating.
If the project already specifies an arrester rated voltage, maximum continuous operating voltage, discharge current, or residual voltage, include those requirements without shortening them to “for 10kV.”
Identify the System Grounding Method
Confirm whether the neutral is effectively grounded, resistance grounded, isolated, or uses another grounding arrangement.
Grounding affects the voltage that a healthy phase may experience during an earth fault. It is therefore an important input to arrester selection.
Two projects with the same nominal system voltage may require different reviews because their grounding and temporary overvoltage behavior differ.
Define Temporary Overvoltage Conditions
Temporary overvoltage is a power-frequency voltage rise that lasts longer than a lightning impulse. It may result from an earth fault or another system condition.
The expected magnitude and duration must be compared with the selected arrester’s capability.
Do not assume that a higher arrester voltage is automatically safer. Raising the arrester rating may reduce protection performance for the connected equipment.
The final choice must balance:
- Continuous operating conditions.
- Temporary overvoltage withstand.
- Required protection level.
The power-system engineer or project protection study should establish these conditions. A supplier should not infer them from the nominal voltage alone.
Compare the Electrical Ratings Correctly
Electrical values on a surge arrester datasheet describe different functions. Treating rated voltage, MCOV, reference voltage, and residual voltage as interchangeable can result in the wrong model.
Arrester Rated Voltage
Arrester rated voltage is a designated voltage value used to identify the arrester’s operating characteristics.
It is not the same as the nominal system voltage. It is also not a statement that the arrester can absorb a surge only up to that number.
For LEEYD’s listed 10kV product range, the six current models shown on the category page have a rated voltage of 17kV. That shared rating does not make their structures interchangeable.
Maximum Continuous Operating Voltage
Maximum continuous operating voltage, commonly abbreviated as MCOV, is the power-frequency voltage that may be applied continuously across the arrester under specified conditions.
LEEYD lists an MCOV of 13.6kV for the current 10kV models on its product page.
The project engineer must confirm that the actual continuous voltage across the arrester is compatible with this value and with the system grounding arrangement.
DC 1mA Reference Voltage
The DC 1mA reference voltage is measured at a specified DC current. It is used as an electrical characteristic for product verification and model comparison.
It is not the system operating voltage.
LEEYD lists 25kV for:
- YH5WS-17/50.
- YH5WS-17/50Q.
- YH5BS-17/50.
- YH5WS-17/50L.
LEEYD lists 24kV for:
- YH5WR-17/45.
- YH5WZ-17/45.
Residual Voltage and Discharge Current
Residual voltage is the voltage appearing across the arrester while it conducts a specified discharge current. It helps engineers compare the arrester’s protective level with the insulation withstand of the protected equipment.
Discharge current, impulse waveform, and residual-voltage values must be compared under the same stated test condition.
Do not compare residual-voltage numbers from different current levels or waveforms as if they were equivalent.
LEEYD’s category page identifies discharge current and residual voltage as model-selection factors. However, it does not publish the full values for every listed 10kV model.
Request the model-specific datasheet when the project requires these parameters.
| Parameter | What It Tells the Buyer | Common Selection Mistake |
|---|---|---|
| Nominal system voltage | The voltage class of the network | Using it as the arrester rated voltage |
| Arrester rated voltage | A designated arrester rating | Treating it as the maximum surge voltage |
| MCOV | Continuous power-frequency voltage capability | Ignoring phase-to-earth voltage and grounding |
| DC 1mA reference voltage | A verification and comparison characteristic | Treating it as normal operating voltage |
| Residual voltage | Protective level at a stated discharge condition | Comparing values measured under different conditions |
| Discharge current | The stated impulse-current condition | Selecting from current value without checking waveform and class |
Match the Arrester to the Protected Equipment
The correct model depends on what the arrester protects and where it is connected.
A transformer terminal, switchgear compartment, distribution line, motor, or capacitor bank may impose different protection and installation requirements.
Identify the Protected Equipment
State the equipment type, insulation requirements available in the project documents, and intended installation point.
The arrester should be located and coordinated as part of the system protection design. It should not be treated as an isolated catalog component.
For transformer protection, the project should consider the connection point and electrical distance between the arrester and transformer terminals.
For switchgear, the design must also consider:
- Compartment space.
- Electrical clearances.
- Cable direction.
- Installation access.
- Maintenance access.
Check Protection Coordination
Protection coordination compares the arrester’s protective characteristics with the insulation withstand of the equipment and the expected overvoltage conditions.
The buyer should provide the applicable project specification or coordination requirements.
If these are absent, the selection should be reviewed by the responsible electrical engineer. A model should not be approved only because another project used the same nominal system voltage.
Confirm the Required Accessories and Configuration
Some projects may require a disconnecting or particular mounting configuration.
LEEYD lists YH5BS-17/50 as a disconnecting and mounting configuration. Other models use standard, compact, extended, or in-line terminal structures.
Confirm whether the project requires:
- A disconnector.
- Mounting bracket.
- Cable lead.
- Terminal hardware.
- Insulating base.
- Monitoring connection.
- Other project-specific accessories.
Availability must be checked for the selected model rather than assumed from the product family name.
Check the Installation Environment and Mechanical Interface
Electrical ratings alone cannot confirm that an arrester will fit or remain suitable in the intended location.
Environmental and mechanical information should be part of the RFQ.
Indoor or Outdoor Installation
State whether the arrester will be installed indoors or outdoors.
For outdoor installations, provide the project requirements for:
- Ambient temperature.
- Altitude.
- Pollution conditions.
- Moisture exposure.
- Required housing structure.
Altitude and pollution can affect insulation and external clearances. The project engineer should confirm the required limits.
Do not assume that every composite-housed model is suitable for every outdoor environment.
Housing and Dimensions
LEEYD’s listed 10kV models use different housing dimensions even when their rated voltage and MCOV are the same.
| LEEYD Model | Rated Voltage | MCOV | DC 1mA Reference Voltage | Shed Diameter | Overall Height | Structural Description |
|---|---|---|---|---|---|---|
| YH5WS-17/50 | 17kV | 13.6kV | 25kV | 70/100mm | 265mm | Standard composite-housed configuration |
| YH5WS-17/50Q | 17kV | 13.6kV | 25kV | 104mm | 220mm | Compact configuration with cable lead |
| YH5BS-17/50 | 17kV | 13.6kV | 25kV | 104mm | 220mm | Disconnecting and mounting configuration |
| YH5WS-17/50L | 17kV | 13.6kV | 25kV | 96mm | 314mm | Extended housing and mounting configuration |
| YH5WR-17/45 | 17kV | 13.6kV | 24kV | 104mm | 250mm | Compact in-line terminal configuration |
| YH5WZ-17/45 | 17kV | 13.6kV | 24kV | 104mm | 250mm | Available in multiple housing structures |
These published values support an initial comparison only.
Confirm the current drawing, terminal details, accessories, tolerances, and complete electrical datasheet before ordering.
Mounting and Connection Details
Provide:
- Available installation height.
- Mounting-hole arrangement.
- Terminal orientation.
- Conductor or cable connection.
- Surrounding electrical clearances.
A nameplate photo may identify an existing model, but it does not replace a dimensioned drawing.
Installation and grounding should follow the approved project design and be performed by qualified personnel.
This selection guide does not replace the system study, local safety rules, or manufacturer installation instructions.
Prepare the Technical and Commercial Documents
A complete project inquiry allows the buyer and supplier to compare the same requirement.
It also reduces the risk of approving a mechanically similar model with different electrical characteristics.
Information Required for a New Project
Prepare the following information where available:
- Nominal system voltage and frequency.
- Phase-to-phase or phase-to-earth voltage basis.
- Grounding method.
- Required arrester rated voltage and MCOV.
- Temporary overvoltage magnitude and duration.
- Required discharge-current and residual-voltage characteristics.
- Protected equipment and installation point.
- Indoor or outdoor environment.
- Altitude, ambient temperature, and pollution conditions.
- Housing, terminal, mounting, and dimensional requirements.
- Applicable project specification.
- Required drawings and test documents.
- Order quantity.
Values that are still under engineering review should be marked as pending. They should not be guessed or silently replaced by standard catalog values.
Information Required for a Replacement
For replacement sourcing, provide:
- Complete old model number.
- Clear nameplate photo.
- Full product photographs.
- Electrical datasheet.
- Terminal details.
- Mounting dimensions.
- Installation location.
- Reason for replacement.
Do not confirm a replacement by appearance, the “10kV” description, or the first part of the model number alone.
Similar housings can contain different electrical ratings. Electrically similar products may also use different mounting structures.
Drawings, Test Data, and Project Records
State whether the project requires:
- Dimensional drawing.
- Technical datasheet.
- Type-test information.
- Routine-test record.
- Compliance document.
- Product labeling.
- Specific language.
- Packing format.
LEEYD states that drawings, dimensional information, technical datasheets, test data, and compliance documents may be available according to the selected model.
Document availability varies by model. Each required item should therefore be confirmed before ordering.
| Review Stage | Information to Confirm | Approval Result |
|---|---|---|
| System review | Voltage, frequency, grounding, and temporary overvoltage | Defines the electrical selection basis |
| Protection review | Protected equipment, discharge condition, and required protective level | Confirms coordination requirements |
| Product review | Rated voltage, MCOV, reference voltage, residual voltage, and discharge current | Identifies an electrically suitable model |
| Installation review | Environment, altitude, pollution, housing, dimensions, terminals, and mounting | Confirms physical and environmental suitability |
| Order review | Drawing revision, documents, quantity, labels, packing, and delivery date | Establishes the controlled supply requirement |
Frequently Asked Questions
Does a 10kV System Use a 10kV-Rated Surge Arrester?
Not necessarily.
The nominal system voltage and arrester rated voltage are different parameters. LEEYD’s currently listed 10kV models have a rated voltage of 17kV and an MCOV of 13.6kV.
Final selection must also consider:
- Grounding method.
- Actual voltage across the arrester.
- Temporary overvoltage.
- Protection coordination.
Do not select a model by matching the two “kV” numbers.
What Is the Difference Between Rated Voltage and MCOV?
Rated voltage is a designated arrester rating. MCOV is the power-frequency voltage that may be applied continuously across the arrester under specified conditions.
Both must be checked against the system design.
The nominal network voltage, phase-to-earth voltage, grounding arrangement, and temporary overvoltage conditions determine whether the values are suitable.
Can Models With the Same 17kV Rating Be Used Interchangeably?
No.
LEEYD’s listed 10kV models share a 17kV rated voltage and 13.6kV MCOV. However, they differ in:
- DC 1mA reference voltage.
- Housing.
- Overall height.
- Shed diameter.
- Terminals.
- Mounting configuration.
Full residual-voltage and discharge-current data may also need comparison.
Confirm the electrical datasheet and drawing rather than approving a replacement from rated voltage alone.
What Information Is Needed to Replace an Existing 10kV Arrester?
Provide the complete model number, nameplate photo, full product photos, rated voltage, MCOV, reference voltage, residual-voltage and discharge-current data when available, dimensions, terminals, mounting arrangement, installation environment, and protected equipment.
Also state the reason for replacement.
A similar appearance or nominal system voltage does not establish compatibility.
Are Product Documents the Same for Every Model?
No.
Available drawings, datasheets, test data, and compliance documents depend on the selected model and project requirements.
State the required standard, test item, language, and document format before ordering.
Do not assume that a document supplied for one housing or rating automatically applies to another configuration.
Review the Available 10kV Arrester Models
Prepare the system parameters, grounding method, protected equipment, temporary overvoltage information, installation environment, dimensions, and required project documents.
Then compare them with the available models on the LEEYD zinc oxide surge arrester page.
The published model table is a starting point, not a substitute for the project protection study.
Final model approval should be based on:
- Complete electrical datasheet.
- Current dimensional drawing.
- Installation requirements.
- Responsible engineer’s protection-coordination review.