Sebuah ATS short-circuit rating cannot be judged from the switch ampere rating alone. This matters especially for compact automatic transfer switches used in distribution boards, generator backup systems and OEM panels: a 40 A or 63 A current marking tells you the normal operating-current range, not whether the ATS is suitable for the prospective fault current at the installation point.
For the LEEYEE compact Class PC ATS covered in this guide, the published product specification declares Iq = 5 kA and lists RT16-00-63A as the recommended fuse. The project engineer still has to compare the actual fault-current level and protection arrangement with the applicable product documentation before approval.
LEEYEE's compact 2P / 4P ATS is specified as Kelas PC, with rated operational currents from 6 A to 63 A and a declared Iq of 5 kA. Do not interpret “5 kA” as permission to install the ATS anywhere the calculated fault current is below 5 kA without further checking. Iq is a conditional short-circuit parameter, so the protection arrangement and the exact manufacturer documentation matter. [2][3]
- Prospective short-circuit current at the ATS location
- LEEYEE product declaration: Iq = 5 kA
- Recommended fuse: RT16-00-63A
- Actual upstream protection used in the panel
The current LEEYEE specification declares Iq = 5 kA but does not state an Icw value. This guide therefore does not invent or derive an Icw rating. If a project specifically requires Icw data, confirm the applicable model-specific technical or test documentation before approval.
Daftar Isi
What Does the 5 kA Iq Rating Mean for This LEEYEE ATS?
In IEC terminology, Iq is the rated conditional short-circuit current. It describes a prospective short-circuit current associated with specified short-circuit protection conditions, rather than a universal standalone current that the transfer switch can interrupt by itself. [2]
The LEEYEE product specification declares Iq = 5 kA. It also separately lists RT16-00-63A as the recommended fuse. These two published product facts are useful for panel design, but the available specification alone does not establish that every RT16-00-63A installation condition is automatically the tested conditional-rating combination.
Do not write “LEEYEE ATS can withstand 5 kA by itself.” The product data declares Iq = 5 kA. Because Iq is a conditional short-circuit parameter, project approval should also verify the applicable protective-device conditions and supporting product or test documentation.
63 A Rated Current and 5 kA Iq Answer Different Questions
The maximum 63 A Ie value describes the normal operational-current range of this compact ATS series. The 5 kA Iq value describes a short-circuit characteristic under its applicable conditions.
| Nilai | Apa yang Disampaikan Kepada Anda | What It Does Not Tell You |
|---|---|---|
| Ie: up to 63 A | Normal operating-current capability for the applicable model. | It does not define the fault current that can be accepted at the installation point. |
| Iq: 5 kA | The product's declared conditional short-circuit current. | It is not a standalone circuit-breaker interrupting rating. |
| RT16-00-63A | The fuse identified as recommended in the LEEYEE product specification. | The product sheet alone does not prove that any substitute MCCB or fuse has identical coordination performance. |
| AC-31B | The utilization category stated for the product. | It is not the short-circuit rating and should not be used as a substitute for Iq or other short-circuit data. |
Makna pembeli: “63 A Class PC ATS, Iq 5 kA” contains two different pieces of information. Both matter, but they answer different engineering questions.
Which ATS Short-Circuit Parameters Should a Panel Builder Look For?
ATS datasheets may include Iq, Icw or other short-circuit information depending on the product and applicable documentation. These terms should not be merged into one generic “kA rating.”
| Parameter | Makna Teknik | How It Applies Here |
|---|---|---|
| Artinya | Rated operational current in normal service. | LEEYEE compact ATS: 6–63 A depending on model. |
| IQ | Rated conditional short-circuit current associated with specified short-circuit protection conditions. | LEEYEE product specification: 5 kA. |
| Icw | Rated short-time withstand current, normally read together with a declared duration. | No Icw value is stated in the current product specification used for this guide. Do not assume one. |
| Arus hubung singkat prospek | The fault current potentially available at the actual ATS installation point. | Must come from the project calculation or short-circuit study. |
| SCPD | The short-circuit protective device intended to clear the fault. | Product specification recommends RT16-00-63A fuse; different arrangements require verification. |
Why This Class PC ATS Depends on the Protection Arrangement
The LEEYEE compact ATS is specified as Kelas PC. In a Class PC application, the transfer switch should not be treated as the device that independently provides the complete short-circuit protection function for the circuit.
The practical engineering question is therefore:
Published IEC-oriented ATS data from major manufacturers illustrate this principle by stating conditional short-circuit ratings together with corresponding fuses or circuit breakers, while separately listing Icw where that parameter is declared. [2][3]
This is why replacing the recommended fuse with a different fuse or MCCB should not be treated as a paperwork-only change. If the protection arrangement differs from the documented configuration, verify the combination before project approval.
Can You Use This 5 kA ATS in Your Panel?
Start with the prospective short-circuit current at the ATS installation point. This value depends on the electrical system, source impedance, transformer characteristics, conductor impedance and installation location. It cannot be determined from the ATS product photo or 63 A current rating.
Situation 1: Project Fault Current and Protection Are Within Verified Product Conditions
If the project fault level, system voltage, ATS model and upstream protection are all covered by the applicable LEEYEE technical documentation, the configuration can move forward to normal project review.
Situation 2: The Project Uses a Different MCCB or Fuse
The product specification recommends RT16-00-63A. If the panel uses another fuse or an MCCB, do not assume that the same Iq performance automatically applies. Ask for confirmation of the specific combination.
Situation 3: Prospective Fault Current Is Above the Published 5 kA Iq
Do not approve this compact ATS by simply adding a larger upstream breaker or by borrowing a higher rating from another ATS model. The project requires a verified protection solution or another ATS configuration whose documented short-circuit capability covers the requirement.
A higher-current ATS from another product family, a competitor's Class PC test result, or a breaker interrupting rating cannot be used as evidence that this LEEYEE 6–63 A ATS has a higher short-circuit capability than the declared product data.
7-Step Verification Process for the LEEYEE Compact ATS
- Calculate the prospective short-circuit current at the ATS location. Use the project's electrical calculation or approved short-circuit study. Do not estimate it from the load current.
- Confirm the exact ATS model and current. The LEEYEE compact series covered here is available from 6 A to 63 A depending on the selected model.
- Confirm voltage and poles. Check the required AC110 V, AC220 V or AC400 V configuration and whether the project needs 2P or 4P.
- Record the declared Iq value. The current LEEYEE product specification states Iq = 5 kA.
- Check the upstream protective device. The product specification recommends RT16-00-63A fuse. If the project uses a different fuse or MCCB, request verification.
- Check the scope of the supporting document. Confirm that any short-circuit test report, certificate or coordination information applies to the exact model, voltage, pole configuration and protection arrangement.
- Stop and confirm when the project is outside the published data. Do not infer an Icw value or a higher Iq from another ATS series.
What If the Consultant Asks for Icw?
Icw is an important short-circuit parameter on many Class PC transfer-switch datasheets. It represents a rated short-time withstand current and is normally stated together with a duration. ABB's IEC ATS data, for example, list Icw separately by time and list conditional Iq with corresponding protection data. [2][3]
However, the LEEYEE technical specification currently available for this compact ATS states Iq = 5 kA and does not state Icw.
If a consultant, panel standard or tender specification explicitly requires Icw, do not convert the 5 kA Iq into an Icw value. Request the required model-specific test or technical documentation before approving the ATS.
How to Read an ATS Datasheet Without Misreading the kA Value
| If You See | Ask This Next | Mengapa Ini Penting |
|---|---|---|
| Iq = 5 kA | What protective-device conditions apply? | Iq is conditional, not a standalone breaker interrupting rating. |
| Recommended fuse: RT16-00-63A | Is this also the verified SCPD for the declared Iq condition? | A recommended fuse entry and a formal short-circuit coordination declaration should not be assumed to be identical without supporting documentation. |
| Icw | What current and duration are declared? | Icw is read together with its time condition. |
| 63 A | Is this Ie or a short-circuit value? | 63 A is the rated operational current for the relevant model, not the fault-current rating. |
| AC-31B | What is the separate short-circuit declaration? | Utilization category and short-circuit rating are different characteristics. |
Aturan pengadaan: never approve an ATS from a single kA number without identifying the parameter, protection condition and exact product scope.
Five Mistakes to Avoid With a 6–63 A Class PC ATS
- Mistake 1 — Treating 63 A as the short-circuit capability. 63 A is a rated operational-current option in this series. The published short-circuit parameter is Iq = 5 kA.
- Mistake 2 — Calling Iq a standalone withstand rating. Iq is a conditional short-circuit current and should be interpreted with its applicable protection conditions.
- Mistake 3 — Inventing an Icw value because the project asks for one. The available LEEYEE product specification does not state Icw. Request model-specific evidence instead.
- Mistake 4 — Replacing the recommended fuse with any MCCB without verification. A different protective device may change the applicable short-circuit coordination conditions.
- Mistake 5 — Applying a large-frame ATS rating to this compact series. Short-circuit declarations from 250 A, 400 A, 630 A or other ATS constructions cannot be transferred to this 6–63 A product.
IEC and UL Documents May Use Different Short-Circuit Language
Panel builders working on international projects may encounter IEC terms such as IQ dan Icw, while UL-oriented transfer-switch documentation often discusses withstand-and-close ratings or WCR. These terms come from different standards and test frameworks and should not be treated as interchangeable labels.
Cummins transfer-switch engineering guidance illustrates the UL-oriented workflow of determining available fault current and then matching the transfer-switch rating and upstream overcurrent protection. The engineering principle is useful, but a UL WCR value should not be converted into an IEC Iq or Icw claim for a LEEYEE product without supporting documentation. [4]
IEC 60947-6-1:2026 is the current fourth edition of the transfer switching equipment standard. It was published in 2026 and replaced the 2021 edition. [1]
What Should You Send Before Short-Circuit Verification?
“I need a 63 A ATS” is not enough information for a short-circuit review. A useful B2B enquiry should include the system data that determines whether the compact ATS and its protection arrangement are suitable.
- Diagram satu garis
- Tegangan dan frekuensi sistem
- Normal-source information
- Backup-source or generator information
- Prospective short-circuit current at the ATS location
- Required ATS current: 6–63 A
- 2P or 4P requirement
- Planned upstream fuse or MCCB
- Protective-device rating and type
- Applicable project standard
- Required short-circuit test or certificate scope
- Kuantitas
- Persyaratan label OEM
- OEM packaging requirement
Need to Check This ATS Against Your Panel Fault Level?
Send your single-line diagram, system voltage, prospective short-circuit current and planned upstream protection. LEEYEE can review which product data or project confirmation is required before quotation or sample approval.
Pertanyaan yang Sering Diajukan
What is the short-circuit rating of this LEEYEE compact ATS?
The available LEEYEE technical specification declares Iq = 5 kA for this compact Class PC ATS series. Because Iq is a conditional short-circuit parameter, the applicable protective-device conditions should also be verified before project approval.
Is this LEEYEE ATS Class PC?
Yes. The supplied LEEYEE product specification identifies this 2P / 4P compact ATS as Kelas PC.
Does the 63 A marking mean the ATS can withstand only 63 A during a short circuit?
No. The 63 A value is a rated operational-current option. The short-circuit parameter published for this series is Iq = 5 kA. These ratings describe different operating conditions.
Does this ATS have an Icw rating?
An Icw value is not stated in the LEEYEE technical specification currently available for this article. It should therefore not be invented or derived from the 5 kA Iq value. If a project requires Icw, request the applicable model-specific documentation.
Which fuse is recommended for this ATS?
The supplied LEEYEE product specification lists RT16-00-63A as the recommended fuse. For project short-circuit approval, confirm whether the exact fuse and installation conditions correspond to the supporting coordination or test documentation.
Can I use an MCCB instead of the recommended fuse?
Do not assume equivalent short-circuit performance automatically. If the actual panel uses an MCCB or another fuse, the protective-device combination should be verified against the applicable LEEYEE technical or test documentation.
Can I use this ATS where the prospective short-circuit current is higher than 5 kA?
The published product data should not be extended beyond its declared short-circuit capability without verified engineering evidence. If the project fault level exceeds the documented rating, request another verified protection arrangement or a different ATS solution rather than assuming suitability.
Is AC-31B the short-circuit rating?
No. AC-31B is the utilization category stated for the product. It is separate from the declared Iq short-circuit parameter.
What information should I send LEEYEE for short-circuit verification?
Send the system voltage, ATS current and pole configuration, prospective short-circuit current at the installation point, planned upstream fuse or MCCB, single-line diagram and any project requirement for Iq, Icw, certificates or test reports.
Confirm the Protection Arrangement Before Final ATS Approval
For an OEM panel or project order, share the actual fault-current level and upstream protection together with the ATS requirement. LEEYEE can confirm which model-specific technical documents are available and what still needs project verification.
Referensi
- Komisi Elektroteknika Internasional (IEC). IEC 60947-6-1:2026 — Low-voltage switchgear and controlgear – Part 6-1: Multiple function equipment – Transfer switching equipment. Edition 4.0. Halaman publikasi resmi IEC.
- ABB. Automatic Transfer Switches — Technical Performance and Selection Considerations. Technical discussion of Class PC transfer switching equipment, rated conditional short-circuit current Iq, rated short-time withstand current Icw and protective-device considerations. ABB ATS technical white paper.
- ABB. TruONE Automatic Transfer Switches — IEC Technical Data. Published Class PC product data showing conditional short-circuit current and short-time withstand information under stated conditions. ABB TruONE ATS catalogue.
- Cummins Pembangkit Listrik. Applying Transfer Switch High WCR / Short-Time Rating to Simplify Electrical System Design. Engineering guidance covering available fault current, transfer-switch short-circuit ratings and upstream overcurrent protection in UL-oriented systems. Cummins technical paper.
- LEEYEE. Compact Automatic Transfer Switch Technical Specifications. Product data supplied for the 6–63 A, 2P / 4P Class PC ATS series, including AC110 / AC220 / AC400 V rated working voltage, Iq 5 kA, RT16-00-63A recommended fuse and AC-31B utilization category. Project-specific certificate and test-report scope should be confirmed before approval.
