| HS Code | Official Doc | Tariff Rate | Origin | Destination | Effective Date |
|---|---|---|---|---|---|
| 8535400000 | Doc | 57.7% | CN | US | 2025-05-12 |
| 8537109170 | Doc | 57.7% | CN | US | 2025-05-12 |
| 8537109160 | Doc | 57.7% | CN | US | 2025-05-12 |
| 8538908160 | Doc | 58.5% | CN | US | 2025-05-12 |
| 8538904000 | Doc | 58.5% | CN | US | 2025-05-12 |
Lightning Arrester
A lightning arrester, also known as a surge arrester, is a protective device designed to protect electrical equipment from transient overvoltages caused by lightning strikes or switching surges.
Material
Lightning arresters utilize various materials depending on the application and voltage level. Common materials include:
- Metal Oxide Varistors (MOV): The most prevalent type, MOVs are ceramic semiconductors with a voltage-dependent resistance. They clamp voltage by providing a low-resistance path to ground when voltage exceeds a certain threshold.
- Silicon Carbide (SiC): Used in medium and high-voltage applications, SiC arresters offer high surge current capability and robustness.
- Expulsion Arresters: Older technology utilizing an air gap and a fiber-reinforced tube. These expel ionized air when a surge occurs, creating a temporary short circuit to ground.
- Valve-Type Arresters: Employ gas discharge tubes or silicon avalanche diodes to conduct surges to ground.
Purpose
The primary purpose of a lightning arrester is to:
- Protect electrical equipment: Safeguard transformers, switchgear, power lines, and other valuable assets from damage due to overvoltages.
- Maintain system continuity: Minimize downtime and service interruptions by limiting the impact of surges.
- Ensure safety: Reduce the risk of fire, equipment failure, and personnel injury.
Function
A lightning arrester functions by:
- Normal Operation: Under normal voltage conditions, the arrester acts as an insulator, allowing current to flow through the protected system without interruption.
- Surge Detection: When a voltage surge exceeds the arrester's clamping voltage, its resistance rapidly decreases.
- Surge Diversion: The arrester provides a low-impedance path to ground, diverting the surge current away from the protected equipment.
- Return to Normal: Once the surge subsides, the arrester’s resistance returns to a high value, restoring normal operation.
Usage Scenarios
- Power Transmission and Distribution Networks: Protecting substations, transmission lines, and distribution transformers.
- Industrial Facilities: Safeguarding motors, generators, control systems, and sensitive electronic equipment.
- Commercial Buildings: Protecting electrical panels, HVAC systems, and data centers.
- Residential Applications: Protecting homes from lightning strikes and power surges (often in the form of surge protectors).
- Telecommunication Systems: Protecting communication towers, base stations, and network infrastructure.
Common Types
- Distribution Class Arresters: Used in distribution systems (typically below 34.5 kV). Commonly utilize MOVs.
- Intermediate Class Arresters: Used in subtransmission systems (34.5 kV to 138 kV).
- Transmission Class Arresters: Used in high-voltage transmission systems (138 kV and above). Often utilize SiC or MOVs.
- Station Class Arresters: Used at substations to protect critical equipment.
- Polymer Arresters: Utilize polymer housings for improved contamination performance and reduced weight.
- Gapless Arresters: Do not rely on air gaps, offering faster response times and reduced degradation.
Lightning arresters are electrical apparatus designed for switching or protecting electrical circuits, or for making connections to or in electrical circuits. Specifically, they are used to protect systems from voltage surges caused by lightning strikes.
The following HS codes are relevant to lightning arresters, based on the provided information:
- 8535400000: This HS code covers electrical apparatus for switching or protecting electrical circuits, or for making connections to or in electrical circuits, for a voltage exceeding 1,000 V. It specifically includes lightning arresters, voltage limiters, and surge suppressors.
- 85: Chapter 85 – Electrical machinery and equipment.
- 35: Heading 8535 – Electrical apparatus for switching or protecting electrical circuits, or for making connections to or in electrical circuits.
- 400000: Subheading 8535.40 – Lightning arresters, voltage limiters and surge suppressors.
Regarding HS code 8535400000, the applicable tax rate is a base tariff of 2.7%, an additional tariff of 25.0%, and an additional tariff of 30.0% after April 2, 2025, resulting in a total tariff of 57.7%.