ZN85-40.5 Indoor Vacuum Circuit Breaker 1250-2000A 25-31.5kA 95/185kV Compact Switchgear Protection Thomas Electric

Product Overview

The ZN85-40.5 is a three-phase AC 50 Hz indoor high-voltage vacuum circuit breaker for 40.5 kV systems in power plants, substations and industrial networks, switching load, overload and fault currents. An upper-and-lower pole layout cuts installation depth, and the spring energy-storage mechanism is integrated in the frame as one compact unit with the moving and fixed parts.

Product Display

ZN85-40.5kv Indoor High-Voltage Vacuum Circuit Breaker - poster_display

Model Designation

ZN85-40.5kv Indoor High-Voltage Vacuum Circuit Breaker - model

Type code: Z N 85 – 40.5 / □ – □

Z — vacuum circuit breaker
N — indoor type
85 — design sequence number
40.5 — rated voltage (kV)
First □ — rated current (A)
Second □ — rated short-circuit breaking current (kA)

Service Conditions

Altitude: not exceeding 1000 m above sea level
Ambient temperature: −25 °C to +40 °C
Relative humidity: daily average ≤ 95%
Surrounding air free from hazardous gases, explosive dust and severe vibration

Construction

A motor charges the closing spring; when the closing electromagnet is energised the stored energy closes the contacts and simultaneously preloads the opening spring and the contact pressure spring. Tripping the opening electromagnet releases the opening spring to separate the contacts inside the sealed vacuum interrupter, where the arc is extinguished without any external quenching medium.

Manual charging is performed by inserting the hand lever into the mechanism and working it through approximately 60 strokes. Once charged, the manual open and close buttons remain operative even if the control supply fails, so the breaker stays serviceable during auxiliary power loss.

Technical Data

Item (Parameter)	Unit	Data
Rated Voltage	kV	40.5
Rated Current	A	1250 1600 2000
Rated Frequency	Hz	50
Rated Short-Circuit Breaking Current	kA	25 31.5
Rated Short-Circuit Making Current (Peak)	kA	63 80
4 s Rated Short-Time Withstand Current	kA	25 31.5
Rated Peak Withstand Current	kA	63 80
1-Minute Power Frequency Withstand Voltage	kV	95
Lightning Impulse Withstand Voltage (Peak)	kV	185
Rated Operating Sequence	—	O – 0.3 s – CO – 180 s – CO
Rated Short-Circuit Breaking Current Operations	times	20
Mechanical Life	times	10000
Opening Time	ms	≤ 80
Single Capacitor Bank Breaking Current	A	630
Back-to-Back Capacitor Bank Breaking Current	A	400
Rated Operating Voltage	V	DC 110 / AC 110 DC 220 / AC 220

Technical note: for special requirements and specific application scenarios beyond the tabulated ratings, contact our technical team for a customised solution.

Standards

The breaker is designed, manufactured and tested in accordance with the applicable IEC and GB standards for high-voltage AC circuit breakers and indoor high-voltage vacuum circuit breakers.

Standards note: routine-test records accompany every shipment; type-test documentation and certification for a required standard edition are available on request.

Installation & Dimensions

Installation Diagram

ZN85-40.5kv Indoor High-Voltage Vacuum Circuit Breaker - installation

The compact upper-and-lower arrangement of poles and mechanism minimises the switchgear depth required by the panel. During installation leave adequate clearance for manual charging, cable termination and maintenance access, and verify earthing and interlock function before first energisation.

Dimension	Value (mm)
Height	2100
Width	1200
Depth	2800
Mounting Hole Spacing (Vertical)	630
Mounting Hole Spacing (Horizontal)	700
Phase Spacing	300

Safety notice: verify clearances and grounding against local electrical codes and the approved outline drawing before energising the installed unit.

FAQs

The breaker is available with 25 kA or 31.5 kA rated short-circuit breaking current, each with the matching 4 s short-time and peak withstand duties. Choose the rating above the calculated fault level of your system and confirm project-specific sizing with our engineering team.

Standard units are rated for installation altitudes up to 1000 m. Above this limit, derating or a customised insulation design is required, so please state the site altitude with your inquiry so that the correct dielectric coordinates can be confirmed.

The breaker withstands 95 kV for one minute at power frequency and 185 kV lightning impulse peak, the standard insulation coordinates for 40.5 kV indoor switchgear. The complete datasheet with test values is available on request.

Every breaker passes routine tests covering mechanical operation, power-frequency withstand voltage and contact resistance measurement. Type tests and third-party certification can be arranged subject to confirmation; a test report template is available from our sales team.

Delivery time depends on the rated current and the extent of customisation. Standard configurations are usually quicker, while special designs are quoted case by case; contact our sales team for the exact schedule of your order.

It serves as the protection and switching device in indoor high-voltage switchgear of power plants, substations and industrial distribution networks, clearing load, overload and fault currents on 40.5 kV systems. State your application scenario for the optimal configuration.

The mechanism is rated for 10000 mechanical operations and the breaker can perform 20 breaking operations at rated short-circuit current. Plan maintenance intervals around your switching duty and confirm them with your technical team.

ZN85-40.5kv Indoor High-Voltage Vacuum Circuit Breaker