ZN12-12 ZN12-40.5G Handcart Indoor Vacuum Circuit Breaker 40.5kV 1250-2000A 25-31.5kA

Product Overview

The ZN12 is a three-phase 50 Hz withdrawable handcart indoor vacuum circuit breaker, offered as ZN12-12 (12 kV) and ZN12-40.5G (40.5 kV). The 40.5 kV version covers currents of 1250-2000 A with breaking of 25 or 31.5 kA, 4 s short-time rating and capacitor breaking of 630 A single / 400 A back-to-back, in compact fully insulated poles for metal-enclosed switchgear.

Product Display

ZN12-12(ZN12-40.5G) Handcart Indoor High Voltage Vacuum Circuit Breaker - display

ZN12-12(ZN12-40.5G) Handcart Indoor High Voltage Vacuum Circuit Breaker - poster_display

Model Designation

ZN12-12(ZN12-40.5G) Handcart Indoor High Voltage Vacuum Circuit Breaker - model

Technical type code: ZN85 − 40.5 C / □ − □ (marketed as ZN12-12 / ZN12-40.5G)

Z — Vacuum circuit breaker
N — Indoor installation
85 — Design sequence number
40.5 — Rated voltage (kV)
C — Handcart (withdrawable) type
First □ — Rated current (A)
Second □ — Rated short-circuit breaking current (kA)

Example: ZN85-40.5C / 2000 − 31.5 identifies a 40.5 kV handcart vacuum circuit breaker of 2000 A rated current with 31.5 kA rated short-circuit breaking current.

Service Conditions

Ambient temperature: −30 °C to +40 °C
Altitude: not exceeding 2000 m (above 1000 m the rated insulation level is raised accordingly)
Relative humidity: daily average ≤ 95%, monthly average ≤ 90%
Seismic intensity: not exceeding degree 8
Air free from corrosive gas vapour, chemical attack, violent vibration, fire and explosion hazard
Service outside these limits: consult the manufacturer for evaluation

Construction

Each phase carries a sealed vacuum interrupter inside a fully enclosed, fully insulated pole assembly, giving a high insulation level of 185 kV impulse and 95 kV power frequency with no fire or explosion risk and no maintenance of the interrupting medium. The spring energy-storage mechanism closes from stored spring energy while the closing and opening coils are energised on command, the spring being charged from an AC or DC 110 / 220 V supply or by manual handle.

The breaker is assembled on a chassis as a withdrawable unit that racks between the connected, test and disconnected positions of metal-enclosed switchgear, allowing isolation or removal while the cubicle remains energised. Primary current transfers through the chassis static contacts, secondary circuits reach the control, protection and measurement loops via the terminal block, and mechanical interlocks together with reliable earthing of frame and switchgear body protect operation and maintenance.

Technical Data

No.	Item	Unit	Data
1	Rated Voltage	kV	40.5
2	Rated Frequency	Hz	50
3	Rated Current	A	1250 1600 2000
4	Rated Short-Circuit Breaking Current	kA	25 31.5
5	Rated Short-Time Withstand Current	kA	25 31.5
6	Rated Short-Circuit Duration	s	4
7	Rated Peak Withstand Current	kA	63 80
8	Rated Short-Circuit Making Current (peak)	kA	63 80
9	Rated Lightning Impulse Withstand Voltage (peak)	kV	185
10	1 min Power-Frequency Withstand Voltage	kV	95
11	Rated Short-Circuit Breaking Time	ms	< 80
12	Opening Time	ms	50
13	Closing Time	ms	≤ 80
14	Rated Operating Sequence	—	O – 0.3 s – CO – 180 s – CO
15	Breaking Operations at Rated Short-Circuit Current	times	20
16	Rated Single Capacitor Bank Breaking Current	A	630
17	Back-to-Back Capacitor Bank Breaking Current	A	400
18	Mechanical Life	operations	10000
19	Rated Operating Voltage (AC/DC)	V	110 220

Selection note: choose the 25 or 31.5 kA rating from the prospective fault current at the switching point and the rated current from the maximum continuous load; for capacitor duty verify the 630 A single-bank and 400 A back-to-back ratings against the bank arrangement.

Standards

The breaker is designed and type-tested to GB/T 1984 for AC high-voltage circuit breakers and to IEC 62271-100, with manufacturing and inspection carried out according to DL/T 403 for indoor high-voltage vacuum circuit breakers of 3.6 kV to 40.5 kV.

Technical note: the 12 kV version (ZN12-12) shares the same construction; its rated values are taken from the nameplate and the approved specification. Parameters beyond the tables follow the technical agreement.

Installation & Dimensions

Installation Diagram

ZN12-12(ZN12-40.5G) Handcart Indoor High Voltage Vacuum Circuit Breaker - installation

The unit is supplied as a withdrawable handcart breaker on a chassis that racks between the connected, test and disconnected positions, so it can be isolated or withdrawn without de-energising the cubicle. Before commissioning, verify the interlocks, confirm nameplate ratings against the panel duty and earth the breaker frame and switchgear body reliably.

Outline Dimension	View	Value (mm)
Overall Width	Front	1148
Pole (phase) Spacing	Front	300 + 300
Base / Wheelbase Width	Front	882
Overall Depth	Side	903
Upper Section Height	Side	400
Lower Section Height	Side	1170

Safety notice: installation, operation and maintenance are reserved for qualified personnel. Before energising, verify type, rated voltage, rated current and breaking rating against nameplate and terminal markings; during service keep the breaker open, earthed and de-energised for work. Never commission a unit with a lost-vacuum interrupter, and never bypass the mechanical interlocks.

FAQs

The underlying technical code is ZN85: Z marks a vacuum circuit breaker, N indoor use and 85 the design sequence number, followed by the voltage figure (40.5 here) and C for the handcart withdrawable type; the two boxes then set rated current in amperes and rated short-circuit breaking current in kiloamperes. The marketing names ZN12-12 and ZN12-40.5G cover the 12 kV and 40.5 kV versions.

A spring energy-storage mechanism that closes from stored spring energy; the closing and opening coils are energised on command, and the spring is charged from an AC or DC 110 / 220 V supply or by manual handle.

The 40.5 kV version is offered with rated currents of 1250, 1600 and 2000 A, rated short-circuit breaking currents of 25 or 31.5 kA, an equal 4 s short-time withstand rating, and peak withstand and making currents of 63 or 80 kA.

The rated lightning impulse withstand voltage is 185 kV peak and the 1 min power-frequency withstand voltage is 95 kV, the standard insulation levels expected of 40.5 kV indoor switchgear.

Yes. It is rated to break 630 A of single capacitor bank current and 400 A of back-to-back bank current, and with a mechanical life of 10000 operations it withstands frequent capacitor switching schedules.

State the version (ZN12-12 or ZN12-40.5G), rated current, rated short-circuit breaking current, short-time duration, control and charging supply voltage, the switchgear cubicle and chassis type, and any special service conditions.

ZN12-12(ZN12-40.5G) Handcart Indoor High Voltage Vacuum Circuit Breaker