# Q Series 6kV/3kA Radial-Leaded Metal-Oxide Varistors

> Surge-type radial-leaded zinc-oxide varistors designated 6 kV / 3 kA, 10D–20D; varistor voltage 82–1,100 V, max. peak current 10 kA (8/20 µs).

- Series code: Q
- Product line: [Varistors](https://www.songtian-ste.com/en/products/metal-oxide-varistors/) › Radial-leaded varistors
- Part numbers: 656 · [part list (JSON)](https://www.songtian-ste.com/data/parts/q-annex-q.json)
- Page: https://www.songtian-ste.com/en/products/metal-oxide-varistors/q-annex-q/
- Chinese version: https://www.songtian-ste.com/zh/products/metal-oxide-varistors/q-annex-q/
- [Ask AI about this series](https://www.songtian-ste.com/en/products/metal-oxide-varistors/q-annex-q/?ask=Help%20me%20choose%20a%20part%20from%20the%20STE%20Q%20series.)

## Key specifications

| Parameter | Value |
| --- | --- |
| Nominal varistor voltage | 82–1,100 V |
| Max. peak current (8/20 µs) | 3,500–10,000 A |
| Surge designation | 6 kV / 3 kA |
| Max. continuous voltage | 50–680 VAC / 65–895 VDC |
| Max. energy (10/1000 µs) | 30–720 J |
| Operating temperature | −40 °C to +125 °C |

## Engineering details

### Overview

Surge-type (Q) radial-leaded metal-oxide varistors with zinc-oxide discs, designated 6 kV / 3 kA. Disc sizes 10D, 14D and 20D, nominal varistor voltage 82–1,100 V, max. continuous voltage 50–680 VAC / 65–895 VDC. Max. peak current 3,500–10,000 A (8/20 µs, one pulse), max. energy 30–720 J (10/1000 µs). Operating temperature −40 °C to +125 °C.

#### Series features

- Three disc sizes, 10D, 14D and 20D; nominal varistor voltage 82–1,100 V
- Max. continuous voltage 50–680 VAC and 65–895 VDC
- Max. peak current, 8/20 µs, one / two pulses: 3.5 / 2.5 kA (10D), 6 / 4.5 kA (14D), 10 / 6.5 kA (20D)
- Operating temperature −40 °C to +125 °C

#### Typical applications

- Equipment surge-immunity designs for a 6 kV / 3 kA generator condition
- Power supplies, smart meters, PLC and communications equipment
- Appliances, industrial controls, lighting and photovoltaic equipment
- Relays, solenoids and semiconductor switching networks

### Specifications

|   |   |
| --- | --- |
| Function | Radial-leaded zinc-oxide varistor for transient overvoltage clamping. The varistor alone is not an equipment immunity result, an SPD, a fuse or a thermal disconnector. |
| Type designation | Q = surge type, designated 6 kV / 3 kA |
| Nominal varistor voltage | 82–1,100 V at 1 mA; 10D from 390 V, 14D and 20D from 82 V |
| Max. continuous AC voltage | 250–680 VAC (10D) · 50–680 VAC (14D, 20D) |
| Max. continuous DC voltage | 320–895 VDC (10D) · 65–895 VDC (14D, 20D) |
| Max. peak current 8/20 µs, 10D | 3,500 A one pulse · 2,500 A two pulses; clamping voltage measured at IP = 25 A |
| Max. energy 10/1000 µs, 10D | 82–180 J (390–1,100 V) |
| Rated power / capacitance, 10D | 0.4 W · 90–300 pF at 1 kHz (reference) |
| Max. peak current 8/20 µs, 14D | 6,000 A one pulse · 4,500 A two pulses; clamping voltage measured at IP = 50 A |
| Max. energy 10/1000 µs, 14D | 30–365 J (82–1,100 V) |
| Rated power / capacitance, 14D | 0.6 W · 180–3,700 pF at 1 kHz (reference) |
| Max. peak current 8/20 µs, 20D | 10,000 A one pulse · 6,500 A two pulses; clamping voltage measured at IP = 100 A |
| Max. energy 10/1000 µs, 20D | 100–720 J (82–1,100 V) |
| Rated power / capacitance, 20D | 1.0 W · 360–7,500 pF at 1 kHz (reference) |
| Max. clamping voltage | Specified per part number at one test current IP per disc size (25 / 50 / 100 A). Compare only at the same current and waveform. |
| Pulse ratings and 6 kV / 3 kA | One- and two-pulse 8/20 µs ratings do not define a 6 kV / 3 kA immunity test sequence. |
| Q vs. Z series, electrical | Continuous voltage, varistor voltage, clamping voltage, peak current, rated power and capacitance equal the Z series at the same disc size and voltage; only the 10/1000 µs energy differs. |
| Q vs. Z series, energy | Equal or higher 10/1000 µs energy: 10D +12–36 J (about 16–34%); most 14D values up to +16 J; 20D equal |
| Q vs. Z series, dimensions | 10D: D max. +1.0 mm, T max. +0.5–2.0 mm; some 14D and 20D values: T max. +0.5–2.0 mm |
| Operating temperature | −40 °C to +125 °C |
| Dimensions, 10D | D max. 13.5 mm · T max. 5.5–9.5 mm · lead pitch F 7.5 ±0.5 mm · lead Ø d 0.7 ±0.05 mm |
| Dimensions, 14D | D max. 16.0 mm · T max. 4.0–9.5 mm · lead pitch F 7.5 ±0.5 mm · lead Ø d 0.7 ±0.05 mm |
| Dimensions, 20D | D max. 21.0 mm · T max. 4.0–9.5 mm · lead pitch F 10.0 ±0.5 mm · lead Ø d 1.0 mm straight / 0.8 mm bent, ±0.05 mm |
| Lead forms | Long straight · single outward bend · short straight · front/rear raised |
| Lead length | Long straight ≥16 mm; short or bent 2.5–<6 mm ±0.5 mm or 6–10 mm ±1.0 mm. Coating run-down, bend height and taped H0 depend on the lead form. |
| Packing | Bulk or taped; taping for 7.5 and 10 mm lead pitch, component pitch 25.4 mm |
| Hand soldering and rework | 350 °C max. · 3 s max. · solder point at least 2 mm from the coating |
| End-of-life protection | Sustained abnormal voltage can raise leakage current and heat the varistor. Coordinate a fuse or thermal disconnector. |
| Further data on request | 6 kV / 3 kA test standard, waveform, generator impedance, coupling, polarity, phase angle, pulse count and interval, operating mode and acceptance criteria · pulse recovery and post-pulse limits of varistor voltage, clamping voltage and leakage · derating of continuous voltage, peak current, energy and leakage current up to +125 °C · max. standby and post-surge leakage current, V-I curves, dynamic resistance and temperature coefficients of clamping and varistor voltage · TOV and failure-mode data · 6 kV / 3 kA test reports, repetitive-pulse curves and endurance, damp-heat, thermal-cycling, vibration, lead-strength and solderability results |

### Variants

Ranges by dielectric, package and lead style within this series.

| Variant | Body dimensions | Varistor voltage / max. continuous voltage | Peak current (8/20 µs, one / two pulses) / energy (10/1000 µs) / rated power | Lead / land pattern | Notes |
| --- | --- | --- | --- | --- | --- |
| 10D-Q | D max. 13.5 mm · T max. 5.5–9.5 mm | 390–1,100 V · 250–680 VAC · 320–895 VDC | 3,500 / 2,500 A · 82–180 J · 0.4 W | F 7.5 ±0.5 mm · d 0.7 ±0.05 mm | Compact Q size; 10/1000 µs energy higher than the 10D Z type at every voltage. |
| 14D-Q | D max. 16.0 mm · T max. 4.0–9.5 mm | 82–1,100 V · 50–680 VAC · 65–895 VDC | 6,000 / 4,500 A · 30–365 J · 0.6 W | F 7.5 ±0.5 mm · d 0.7 ±0.05 mm | Widest voltage range in the series. Energy equal to or higher than the 14D Z type. |
| 20D-Q | D max. 21.0 mm · T max. 4.0–9.5 mm | 82–1,100 V · 50–680 VAC · 65–895 VDC | 10,000 / 6,500 A · 100–720 J · 1.0 W | F 10 ±0.5 mm · d 1.0 mm straight / 0.8 mm bent, ±0.05 mm | Highest peak current and energy in the series. Electrical ratings equal the 20D Z type; select Q for its construction and a system surge test. |

### Selection guide

Treat 6 kV / 3 kA as an equipment surge requirement and define the complete generator and pass criteria. Then select max. continuous voltage, clamping at the protected load, disc size and energy, pulse sequence, temperature, TOV and fail-safe disconnection.

1. **Define the 6 kV / 3 kA test method**
   Name the governing standard and edition, 1.2/50 µs and 8/20 µs tolerances, generator impedance (2 Ω or other), coupling network, polarity, phase angle, pulse count and interval, operating mode, number of specimens and acceptance criteria.
2. **Select max. continuous VAC/VDC first**
   Include line tolerance, frequency, harmonics, grounding and every TOV duration. Do not use the nominal varistor voltage as the continuous rating.
3. **Coordinate clamping with protected-load withstand**
   Use the V-I curve and temperature tolerance (on request). Include generator voltage collapse during clamping and lead/PCB inductive overshoot, and measure the residual voltage at the actual protected load.
4. **Check energy, pulse count and temperature margin**
   Check derating versus pulse count, interval, waveform duration and temperature up to +125 °C, and the post-stress limits for varistor voltage, clamping voltage and leakage (data on request).
5. **Specify part number, approvals and safe end of life**
   Fix disc size, voltage, construction, drawing, marking, lead form, packing, temperature grade and approvals with the exact part number. Coordinate fuse or thermal disconnection, enclosure, soldering and inspection or replacement.

### Approvals & reliability

#### Approvals & qualifications

Approval coverage depends on voltage value, construction, temperature grade, lead form and factory. The approvals below are component approvals, not an equipment-level 6 kV / 3 kA test report. Certificate copies on request.

| Agency | Standard | Certificate | Scope |
| --- | --- | --- | --- |
| CQC CQC | GB/T 10193 · GB/T 10194 · GB 8898 · GB 4943.1 | 10D 19001213188 · 14D 19001213191 · 20D 19001213192 | Covers defined voltage values, constructions and temperature grades. |
| UL UL / cUL | UL 1449 | E330837 | Recognized component. Component recognition alone does not establish IEC 61000-4-5 immunity, IEC 62368-1 Annex G compliance or an SPD classification. |
| VDE VDE | IEC 61051 · IEC 60950-1:2013 | 40023049 | Covers specific voltage values. Model list and constructions on request. |

Each certificate covers the types and ratings listed on it.

### Design notes

#### A 6 kV / 3 kA designation is not a test plan

Define the waveform tolerances, source impedance, coupling, polarity, phase angle, pulse count, interval, operating mode and pass criteria. Equipment immunity cannot be inferred from the ratings of one varistor.

#### Separate limit, nominal and repetitive current

The one-pulse 8/20 µs peak current is a limit value, not a repetitive rating. Distinguish it from repeated surge current, the 6 kV / 3 kA test sequence and the lifetime margin.

#### Q and Z ratings differ only in energy

At equal disc size and voltage, Q and Z share all ratings except the 10/1000 µs energy, which is equal or higher for Q. Select Q for its construction and a validated system surge test, not for the suffix alone.

#### Coordinate TOV, fuse and thermal disconnection

Sustained abnormal voltage can raise leakage current and heat the varistor, even after a passed surge test. Coordinate available fault current, fuse or thermal protector, enclosure and safe indication or replacement.

### Part numbering

Example ordering code. Not every combination is available.

`STE · 10 · D · 471 · K · 1 · E · N0 · F · Q · B · 0 · R · 0`

| Code | Meaning |
| --- | --- |
| STE | STE prefix |
| 10 | Disc diameter: 10 = 10 mm; 14, 20 for the other sizes |
| D | Disc shape |
| 471 | Nominal varistor voltage: 471 = 470 V; range 820 (82 V) to 112 (1,100 V); 10D from 391 (390 V) |
| K | Varistor-voltage tolerance: K = ±10% |
| 1 | Lead form: 1 = long straight; 2 = single outward bend, 3 = short straight, 8 = front/rear raised |
| E | Lead pitch: E = 7.5 mm; D = 10.0 mm (20D) |
| N0 | Lead length or taped height; the code depends on bulk or taped packing (code table on request) |
| F | Lead material: F = tin-plated copper-clad steel; C = copper wire |
| Q | Varistor type: Q = surge type, designated 6 kV / 3 kA |
| B | Packing: B = bulk; T = taped |
| 0 | Factory code, assigned by STE |
| R | Environmental code: R = RoHS; F = RoHS and halogen-free |
| 0 | Factory code, assigned by STE |

## Datasheets & approval documents

- [Datasheet: Q series metal oxide varistors, surge type — short-form datasheet (2023-03)](https://www.songtian-ste.com/documents/source-cn/%E5%8E%8B%E6%95%8F%E7%94%B5%E9%98%BB%E5%99%A8%E7%B3%BB%E5%88%97%E4%BA%A7%E5%93%81%E8%A7%84%E6%A0%BC%E4%B9%A6/%E5%8E%8B%E6%95%8F%E7%94%B5%E9%98%BB%E5%99%A8-Q%E7%B3%BB%E5%88%97%28%E6%B5%AA%E6%B6%8C%E5%9E%8B%29%E7%AE%80%E7%89%88%E8%A7%84%E6%A0%BC%E4%B9%A6-202303.pdf) — PDF · Chinese · 2023-03 · 343 KB
- [Certificate: Varistor safety approval certificates (2022-11)](https://www.songtian-ste.com/documents/source-cn/%E5%AE%89%E8%A7%84%E8%AE%A4%E8%AF%81%E8%AF%81%E4%B9%A6/1-%E5%8E%8B%E6%95%8F%E7%94%B5%E9%98%BB%E5%AE%89%E8%A7%84%E8%AE%A4%E8%AF%81%E8%AF%81%E4%B9%A6%EF%BC%882022%E5%B9%B411%E6%9C%88%E7%89%88%EF%BC%89.pdf) — PDF · Chinese · 2022-11 · 4.2 MB

## More in radial-leaded varistors

- [S Series Standard Radial-Leaded Metal-Oxide Varistors](https://www.songtian-ste.com/en/products/metal-oxide-varistors/s-standard/)
- [Z Series High-Energy Radial-Leaded Metal-Oxide Varistors](https://www.songtian-ste.com/en/products/metal-oxide-varistors/z-high-energy/)
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