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Surge protectors & arrestors target emerging sectors, enhanced reliability

Adoption of surge protectors and arrestors widens as makers explore the PV market while enhancing product aesthetics and raising exports.

Suppliers of surge protectors and arrestors in China are directing R&D efforts toward meeting requirements of emerging fields such as alternative power sources even as they continue to release traditional models. Guangxi Dikai Science and Technology Co. Ltd and Shenzhen Techwin, for instance, have launched versions for PV devices to take advantage of this thriving market.


Box-type surge arrestor
The DK-220AC80 model from Guangxi Dikai is a box-type surge arrestor with a low residual voltage.

To match increasing orders, manufacturers are improving product appearance and packaging through visually appealing colors and designs. They are likewise introducing variants with better reliability and easy-to-install features.

Expanding current selections is part of the agenda as well. Major players are completing manufacturing lines to offer a range of units that meet safety standards A, B, C and D. The first provides defense against elevated or even ultrahigh voltages, while the last shields values 999V or less. B and C cover figures in between.

As miniaturization remains a trend in electronics, makers are launching more compact surge protectors and arrestors. Although a few can fabricate SMD kinds at present, many will be veering away from the DIP configuration to start adopting the former to reduce labor costs.

These initiatives are expected to help China suppliers ascend the value chain in the worldwide market, which is currently ruled by overseas brands such as Obo and ABB. To achieve recognition, makers are increasing presence in local and international trade exhibitions. Henan HMCY Electronic & Technology Co. Ltd, for example, is planning to attend fairs to be held in Vietnam and Dubai in coming months.

Manufacturers also continue to leverage pricing advantage, offering models 20 to 30 percent less expensive than foreign counterparts. Many are likewise obtaining certification and approval to export products, including UL, FCC and RoHS.

Suppliers expect to equal 2010’s more than 30 percent increase in export sales this year. The confidence comes mainly from the climbing popularity of the line worldwide, with utilization rising 20 percent annually. Applications cover the telecom, railway, building construction, automation, transportation and military industries, with the first three representing 70 percent of demand.

Some local brands that are gaining popularity are Dowin, Zhongguang, Lerdn and Dikai of Shenzhen Dowin, Zhongguang High-Tech Industrial Development Group, Shanghai Lerdn and Guangxi Dikai, respectively.

Various companies have just penetrated the international sector, and their number is projected to rise in the months ahead. The major destinations are the Middle East and Asia, but several large players have also begun exploring Europe and North America.

Despite the shift in focus, the domestic market is forecast to maintain steady growth in the future. This is because utilization in China is sustained by the line’s expanding applications and the regular replacement of older equipment. Telecom facilities, for instance, need to be updated every three to five years.

There are currently 500 suppliers in the country. More than half of them are located in the Pearl and Yangtze River Delta regions. Fewer than 50 specialize in the line and have their own brands.
Selections & specifications
Main components
Product gallery

Selections & specifications

There are two ways to shield an electrical system from interference. One is by disconnecting the circuit, which usually involves a circuit breaker attached in series with protective devices. The other is by providing a discharge channel to divert the energy to the ground. The former cannot prevent transient and large currents or voltages, which is why many prefer using surge protective devices.

The main technical difference between an arrestor and a protector is the latter’s internal monitoring capability, which identifies failure quickly and activates a remote alarm or light to indicate a malfunction. Having a more complex structure, the last also enables EMI/RFI filtering and internal fusing, and features a longer life span. Manufacturers generally give a warranty of at least three to five years for such products, while the first usually has a limited service contract.

Surge arrestors, meanwhile, have a high let-through voltage exceeding 1.2kV, making them suitable for large electrical distribution systems but not for sensitive electronics devices. They are also 30 to 50 percent less pricey, depending on the shape and size. The common applications include conductor wires and transformers.

The key parameter for both products is the response time. The longer this specification, the higher the risks the connected equipment will be exposed to the surge. For power protection, the typical value is 1ns, while it is 25ns to 1s for signals.

There are more than 100 types of surge protectors and arrestors in China. Based on structure, the most common are gap, tube and valve variants. The first with silicon carbide blocks or disks is still being used, but its gapless metal-oxide version is more popular. Tube units adopt gas discharge tubes or GDTs, while the last variety consists of a series of spark gaps and nonlinear resistor disks, which are generally metal-oxide varistors or MOVs.

In terms of profile, the modular configuration is typical because of its easy replacement feature.

For power supplies, there are box versions with one or two ports and sockets. The connectors can be RJ-45, RJ-41, BNC, L16, SL16, TNC, DIN, SMB and SMA.

Products can also be classified according to applications. Some are for power supplies, which include high-voltage power stations and all kinds of distribution systems. Various units are designed to meet signal protection requirements in telephone, network, video or audio lines, and coaxial cables. Others suit antennas for systems with transmitters and wireless receivers.

Guangxi Dikai offers six series of surge protective devices for antennas, power supplies, and industrial control, petrochemical and household equipment. Its DK-220AC80 model is applied in UPS for machine rooms, and has a thunder strike counter and lightning-protection status indicator.

Yangzhou Jingcheng Electronics Co. Ltd’s BL-7/16-JK model is a quarter-wave surge arrestor used in RF antenna devices and receiving systems. It prevents damage from lightning and induced overvoltage, and static discharge.

Henan HMCY turns out two- and three-in-one versions for enhanced protection. The maker’s CY-BL303 model provides security for video, power and control signals, ensuring noninterference among these lines. The products are adopted in CCTV cameras and cable TVs.

Aside from off-the-shelf variants, China suppliers offer customization services on technical specifications, design and material requirements.

Main components

The major inputs for surge protectors and arrestors are the GDTs and MOVs. Relying on a gas trapped between two electrodes that are ionized by the high voltage, the first can conduct more current than other components. The latter, meanwhile, contains a current-conducting material, usually granular zinc oxide, that generates current when a voltage above the rated value occurs. It has a fast response time, large capacity and simple structure, and is expected to replace silicon carbide used in valve-type models in the future.

GDTs and MOVs can be used separately, but a right combination of them can improve the performance of finished protective devices.

Some units, especially those for networking equipment, incorporate a transient suppression diode to limit voltage spikes. Others adopt surge absorbers, capacitors, fuses and circuit breakers in one package to ensure better functionality in a more compact configuration.

Most materials are imported, but some companies source from local providers if clients require. The cost of several inputs increased by as much as 20 percent in 2010, pushing a number of makers to raise prices of surge arrestors and protectors.

This year, many suppliers are planning to implement markups of up to 5 percent but mostly for new clients. The majority will keep quotes stable or even lower them to secure orders. To reduce outlay, a few will employ more automated production equipment.


Modular surge arrestor
Product gallery

Guangxi Dikai Science and Technology Co. Ltd

Model: DK-380AC
MOQ: 100 units
Delivery: 12 days
Description: Modular surge arrestor; PBT/PA-F material; 35mm electrical lead rail; high-energy SPD; 8/20µs wave form; overcurrent fuse protector and thermal inductance breaker; 144x90x66mm; 900g; for lightning protection; CE, RoHS


3-in-1 surge protector


Henan HMCY Electronic & Technology Co. Ltd

Model: CY-BL303
MOQ: 50 units
Delivery: 7 days
Description: 3-in-1 surge protector; 5V, 12VDC, 24 and 220VAC nominal voltage; ≤0.3dB insertion loss; 75ohm impedance; ≤1, 25ns response time; -25 to 65 C operating temperature; 5 to 95% humidity; BNC connector


N-type surge protector


Yangzhou Jingcheng Electronics Co. Ltd

Model: N-JK-G
MOQ: 1 unit
Delivery: 10 days
Description: N-type surge protector; 2.5kV rms dielectric withstand voltage; 50ohm impedance; 11GHz maximum frequency; ≤1mohm center and outer conductor contact, ≥5,000Mohm insulation resistance; -55 to 155 C operating temperature; ≥500 cycles durability


Note:This article was originally published by Global Sources, a leading business-to-business media company and a primary facilitator of trade with China manufacturers and India suppliers, providing essential sourcing information to volume buyers through our e-magazines, trade shows and industry research.

All price quotes in this report are in US dollars unless otherwise specified. FOB prices were provided by the companies interviewed only as reference prices at the time of interview and may have changed.

Disclaimer: All product images are provided by the companies interviewed and are for reference purposes only. Those product images featuring products with trademarks, brand names or logos are not intended for sale. We, our affiliates, and our affiliates' respective directors, officers, employees, representatives, agents or contractors, do not accept and will not have any responsibility or liability for product images (or any part thereof) which infringe on any intellectual property or other rights of a third party.



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