Of all similar SPD testers, it is probably the lightest,

smallest tester with the most accurate test data

and the most durable battery

Portable Surge Protective Device Tester

Model：WTH-CS/BT-1000V
Ordering Code：US128002
User Manual: Download



WTH-CS/BT-1000V Portable SPD Tester applies to the measurement of the parameters of the voltage-limiting type and switch-type SPDs. These data are used for evaluating the operating characteristics of the SPDs and the product selection to cooperate with the construction site.

Working Principle of a Surge Protective Device

The core component of a surge protector is a nonlinear component inside. According to the different nonlinear components, surge protectors can be classified as switch-type (the core component is mainly GDT) and voltage-limiting type (the core component is mainly MOV).
Although the working principles of GDT and MOV are different, the basic characteristics are very similar: when there is no over voltage, their impedance is very high, generally megohm level, which is almost equivalent to an open circuit. When an over voltage occurs, the impedance quickly drops to a few ohms, and the surge current will flow into the ground through the surge protector instead of entering the equipment. At the same time, as the impedance of the surge protector at this time is small, the voltage on both sides is also relatively small, and it is connected in parallel with the protected equipment, it also prevents the equipment from withstanding large surge voltages. In this way, it has the effect of draining and limiting the pressure.

Importance of Leakage Current Parameters

With the extension of the service life of the voltage-limiting surge protector, the gradual aging of the MOV chip will be accompanied by an increase in leakage current. The increase in leakage current will cause overheating, accelerated aging, and failure of the surge protector.
If we do not pay attention to the aging curve of the surge protector and replace it in time, once the surge protector cannot disconnect in time when getting overheating due to increasing in leakage current, it will more likely cause an explosion, and more seriously, it may cause a fire.

Importance of Break-over Voltage Parameters

The break-over voltage of surge protector is the voltage value measured when the current flowing through the surge protector is 1 mA when the test voltage increases.
Has the surge protector in the system been broken down?
Can the SPD which has been used for years continue to be used?
If the L-PE voltage of the power grid system is 277V, is the selected surge protector correct?
Normally only the value of UC is marked on the surge protector. What is the actual break-over voltage in response to the surge current?
All of problems above will be solved when break-over voltage parameters are measured.

Main Features of WTH-CS/BT-1000V Tester:

1. Portable and convenient use with batteries, rechargeable batteries or external power supply; suitable for office and onsite measurements
2. Easy, rapid and precise measurement by pressing one button for testing and immediate display SPD data features
3. While MOV testing, a buzzer will sound if the deviation of break-over voltage exceeds the default value by ± 5%.
4. While MOV testing, a buzzer will sound if the leakage current exceeds 20 μA.
5. Applied to testing both MOV-type and GDT- type SPDs
6. Precise test the break-over voltage under the constant current 1mA
7. Precise test the leakage current under 75% of the break-over voltage
8. The voltage of the tester can be boosted up to 1000V DC
9.Convenient multimeter calibration methods

Technical Specification of WTH-CS/BT-1000V:

Range of break-over voltage for testing Un(U1mA): 0~1000V
Range of leakage current for testing: 0~25μA, ±2.5%, ±0.5μA
FUNCTION 1 testing mode: for testing voltage-limiting type SPDs, break-over voltage and leakage current will display in about 2.5 seconds.
Range of breakdown voltage for testing: 0~1000V, ±2.5%, ±5V(120-1000V)
FUNCTION 6 testing mode: for testing switch-type SPDs, boost the DC voltage step by step at a speed of 100V/second for an precise measurement of breakdown voltage.
Minimum resolution of the break-over Voltage: 1V
Minimum resolution of the leakage current: 0.1μA
Operation temperature: 32°F ~ +122°F (0°C ~ +50°C)
Power supplies: four AA1.2V rechargeable batteries, four AA1.5V batteries or 5V2.5A external power transformers
Weight: 570g/1.26 lb (Without accessories)
Dimensions: 245mm×120mm×50mm(9.65in×4.72in ×1.97in)

Testing data for reference:

AC Network	Uc (AC)	U1mA	Testing Model
110V, 120/208V	150V	257-298V	WTH-40/C/R/1P-150
220/380V	275V	447-518V	WTH-40/C/R/1P-275
220/380V, 277/480V	385V	590-683V	WTH-40/C/R/1P-385
347/600V	550V	780-903V	WTH-40/C/R/1P-550