ZN12-40.5 vacuum circuit breaker is designed for a rated voltage of 40.5kV, and for use in three-phase AC 50(60)Hz indoor medium-voltage switchgear. This circuit breaker has a simple structure, strong breaking capacity, and is suitable for use in power distribution systems, such as those in industrial enterprises and substations. It is especially suitable for industries requiring frequent operation, such as metallurgy and arc steelmaking, serving as a control and protection switch.

The circuit breaker utilizes air insulation, which meets the insulation requirements for normal operating conditions. It has a well-organized layout and a simple, easy-to-adjust structure.

Inside the circuit breaker, there is a simple and reliable mechanical interlocking interface, making it easy to meet the "five prevention" requirements for switchgear.

Product Portfolio and Brand Strength
We offer a wide range of products, including indoor and outdoor vacuum circuit breakers, switchgear, low voltage switch equipment, and various electrical accessories. Each product is designed to meet the specific needs of our customers, they can operate stably in urban distribution networks, industrial melting, new energy power generation, rural power supply and other places, and can still maintain excellent reliability even in harsh environments. Our VTZ Series have become important switch equipment in major fields and power systems throughout China, and their reputation for reliability has earned us the trust of customers nationwide.

After-sales and Service
We are committed to providing exceptional after-sales support to our global customers. Our services include worldwide technical support and warranty coverage, such as online remote technical support, video training, and on-site installation guidance. During the warranty period, we respond quickly to equipment defaults, and provide repair or replacement services, with the option to extend warranties as needed. To ensure effective communication, we also offer multilingual support and provide a comprehensive feedback mechanism that allows us to track customer satisfaction and continuously improve our service quality.

Specification Sheet

No.	Name	Unit	Data
1	Rated Voltage	kV	40.5
2	Rated Frequency	Hz	50
3	Rated Current	A	630/1250/1600/2000/2500
4	Rated Power Frequency Withstand Voltage	kV	95(Across the Contact Gaps) / 95(To Ground)
5	Rated Lightning Impulse Withstand Voltage	kV	185
6	Rated Short-Circuit Breaking Current	kA	25/31.5
7	Rated Short-Circuit Making Current (Peak)	kA	63/80
8	Rated Withstand Current (Peak)	kA	63/80
9	Rated Duration of Short-Circuit	s	4
10	Operating Cycles at Rated Short-Circuit Breaking Current	Times	E2
11	Mechanical Endurance	Times	30000
12	Standard Operating Sequence	-	O-0.3s-CO-180s-CO
13	Allowable Wear Thickness of Contact	mm	≤3

Mechanical characteristics

No.	Name	Unit	Data
1	Clearance between Moved and Fixed Contact	mm	22±2
2	Contact Overtravel	mm	6±1
3	Average Closing Speed	m/s	0.6±0.2
4	Average Opening Speed (Average Speed of First Opening at 12mm)	m/s	1.7±0.3
5	Rated Contact Pressure	N	3100±200N(25kA/31.5kA)
6	Closing Time	ms	30～120
7	Opening Time	ms	20～75
8	Contact Bouncing Duration at Closing Operation	ms	≤3
9	No-Simultaneity of Closing/Opening Operations of 3-Phase	ms	≤2