What is Surge Test?

What is Surge Testing?

Surge testing (Surge Test), also known as impulse testing or transient overvoltage testing, is an electromagnetic compatibility (EMC) test used to evaluate the ability of electrical or electronic equipment to withstand high-voltage transient pulses. These transient pulses are typically caused by power grid switching operations, lightning induction, or the start-up and shutdown of high-power equipment.

Purpose of Surge Testing

To verify the anti-interference capability and reliability of our sensors under power surge conditions, ensuring compliance with IEC 61000-4-5 and suitability for outdoor or high-EMI environments.

Test Standards and Levels

Surge immunity levels are defined by IEC 61000-4-5, with each level indicating the maximum surge severity the equipment can withstand.

Standard	Test Level & Application	Test Waveform	Voltage / Current	Polarity
IEC 61000-4-5	Level 1 (well-protected indoor environment)	Combination wave (1.2/50 μs voltage wave + 8/20 μs current wave)	±500 V (line-to-line)	5 times positive / 5 times negative
	Level 2 (general industrial environment)		±1000 V (line-to-line)
	Level 3 (industrial sites, pump stations, outdoor control cabinets, etc.)		±2000 V (line-to-line)
	Level 4 (harsh industrial environments, such as areas with high lightning risk)		±4000 V (line-to-line)

Acceptance Criteria

Test Item	Grade A (Industrial Grade)	Grade B (General Grade)
Performance requirements	No damage during testing, signal fluctuation ≤ ±2% FS, automatic recovery	Short interruption allowed (<10 s), normal operation after manual reset
Hardware damage	No burning or PCB carbonization	No permanent damage

Test Equipment

DC power supply, RS485, test PC, SUG61005TB surge generator

In this test, our HPT604 level sensor is tested at Level 3.

Test Procedure

Power port test (DC 24 V supply): The surge is injected into the power terminals through a coupling network (±500 V, ±1 kV, ±2 kV).

Operating Steps

• The device is connected to a PC via RS485, powered on, and communication with the host software is established.
• ±500 V, ±1 kV, and ±2 kV surges are applied sequentially between (L-N), with an interval of 60 seconds per application.
• Record whether restart, damage, or output deviation occurs.
• After testing, each sample undergoes one forward and one reverse linearity test, and the data are recorded.

Test Results

Multiple HPT604 sensors are tested.

Sample 3 experienced 420 surges; Sample 1 experienced 500 surges, far exceeding the standard requirement (5 times).

All test results showed no damage to the products, with minimal signal fluctuation during testing. The HPT604 meets Level 3 requirements.