Overview
The LQZJ-0.66 is a low-voltage, indoor-type current transformer designed for 0.66 kV class AC distribution systems operating at 50 Hz or 60 Hz. It features a single-ratio, single-phase configuration with a Ø103 mm primary aperture to accommodate busbars or insulated cables. The unit provides galvanically isolated secondary output of 5 A (standard), scaled according to the nameplate ratio, for use with energy meters, ammeters, transducers, and protection relays.
Built with epoxy-resin vacuum-cast insulation and a compact post-type housing, the LQZJ-0.66 ensures high dielectric strength, stable partial-discharge performance, and compliance with IEC 61869 and GB standards. Its robust design supports both metering (accuracy classes 0.2, 0.5, 1) and protection (10P) applications in switchgear, motor control centers, and building energy management systems.
Key Ratings Snapshot
| Parameter | Rating |
|---|---|
| System voltage class (Um) | 0.72 kV (for 0.66 kV systems) |
| Rated frequency | 50 Hz or 60 Hz |
| Rated primary current (I₁n) | 5–1000 A (discrete steps) |
| Rated secondary current (I₂n) | 5 A (1 A optional) |
| Accuracy class | 0.2, 0.5, 1 (metering); 10P (protection) |
| Rated output (Sn) | 10 VA (class 0.2/0.5); 15 VA (class 1/10P) |
| Short-time thermal current | 50 × I₁n for 1 s |
| Dynamic current | 100 × I₁n peak |
| Primary aperture | Ø103 mm |
| Insulation system | Epoxy resin cast, thermal class B (130 °C) |
| Standards | IEC 61869-1/2, GB/T 20840.1/2, GB 1208 |
| Mounting | Bottom or side panel; 2-hole or 4-hole M6 pattern |
Model Designation
The model code LQZJ-0.66 follows Chinese instrument-transformer nomenclature:
- L – Current transformer (电流互感器)
- Q – Toroidal / ring-wound construction (浇圈式)
- Z – Cast-resin insulated, fully enclosed (浇注绝缘)
- J – Increased capacity / enhanced output (加大容量)
- □ – Design sequence number (manufacturer-specific)
- 0.66 – Rated voltage class in kV (660 V)
Construction
The LQZJ-0.66 employs a toroidal core made of grain-oriented silicon steel (CRGO), annealed for optimal magnetic performance; nickel-iron alloy cores are used for low-current variants (≤50 A). The primary circuit is a single-turn pass-through via the Ø103 mm aperture, with no dedicated terminals. The secondary winding consists of multi-turn copper magnet wire with Class B or F enamel insulation, uniformly wound and integrated into the assembly before encapsulation.
The entire core-and-coil unit is vacuum-cast in epoxy resin, forming a monolithic, fully enclosed insulation system rated for thermal class B (130 °C), with class F (155 °C) available on request. An outer flame-retardant thermoplastic housing (UL94 V-0) provides mechanical protection and IP20 ingress rating. Secondary terminals S1/S2 are brass studs (M5/M6) with locking hardware, marked for subtractive polarity per IEC 61869-2. Mounting options include bottom or side interfaces with selectable 2-hole or 4-hole patterns using M6 screws.
Technical Parameters
Service Conditions
- Installation: Indoor only
- Altitude: ≤ 2000 m a.s.l.
- Ambient temperature: −5 °C to +40 °C
- Relative humidity: ≤ 95% daily average / ≤ 90% monthly average (non-condensing)
- Atmosphere: Free from corrosive gases, conductive dust, explosive media
- Vibration: ≤ 0.5 g, no severe shock
- Pollution degree: PD 2 per IEC 60664-1
Technical Parameters
This section provides selection-grade electrical data for the LQZJ-0.66 series. All values apply at the rated burden and rated frequency as marked on the nameplate. For configurations outside the standard ranges, technical agreement and a project-specific datasheet shall govern.
| Rated primary
current (A) |
secondary
current (A) |
output (VA) | (Ith) short-time
thermal current (kA) |
(Idyn)dynamic
current (kA) |
||
|---|---|---|---|---|---|---|
| 0.2 | 0.5 | 1 | ||||
| 5, 10, 15, 20, 30, 40, 50, 75, 100, 150, 200, 300, 400, 600, 800, 1000 |
5 | 10 | 10 | 15 | 50 I1n | 100 I1n |
Installation & Wiring
Outline Dimensions
The LQZJ-0.66 current transformer features an overall width of 140 mm (max.), height of 127.5 mm, and depth of approximately 103 mm. The primary aperture is Ø103 mm, allowing central passage of busbars or cables. Mounting is achieved via a base length of 110 mm with either a 2-hole or 4-hole pattern spaced at 56 mm × 89 mm (refer to certified drawings for exact coordinates). Four Ø5 fixing slots accommodate M6 hardware. Net weight ranges from 0.8 to 1.2 kg depending on configuration.
Wiring Diagram
Connect the secondary terminals S1 and S2 to the metering or protection device in accordance with polarity markings: current entering P1 produces output from S1 to S2. S1 connects to the live input of the instrumentation, while S2 connects to its neutral. Earth the secondary circuit at one point only—typically S2 at the marshalling kiosk or protection panel terminal block. Never leave the secondary open when the primary is energized.
Selection & FAQs
Selection Guide
- Select the 5A–1000A primary ratio from the normal load, maximum current, and protection study.
- Confirm that the 103mm aperture fits the cable or busbar assembly with adequate insulation clearance.
- Choose a 5A or optional 1A secondary and specify metering or 10P protection accuracy.
- Calculate the total burden and select 10VA or 15VA according to the required class and connected circuit.
- Confirm the 2-hole or 4-hole mounting pattern, conductor direction, polarity, grounding, and terminal access.
Frequently Asked Questions
Q1: Can this 0.66kV epoxy resin CT be installed outdoors?
No, it is strictly for indoor installation only. It requires an environment free from corrosive gases and conductive dust. Contact us for outdoor-rated alternatives.
Q2: How is the short-circuit withstand capacity rated?
The short-time thermal current (Ith) withstands 50 times the primary current. The dynamic current (Idyn) handles 100 times the primary current. Verify specific fault levels with our engineering team.
Q3: Which accuracy class is designated for precision metering?
The 0.2 accuracy class is designated for precision metering applications. It supports a rated output of 10 VA at a 5A secondary current. Confirm your specific burden requirements during ordering.
Q4: Is this current transformer suitable for high-altitude installations?
It is suitable for altitudes up to 2000 meters above sea level. For installations exceeding this limit, derating or special design modifications apply. Please provide your site elevation for technical review.
Q5: Can we customize the primary current ratio?
Yes, primary currents from 5A to 1000A are available within the standard range. Ratios outside these standard values require a project-specific datasheet and technical agreement. Submit your exact ratio requirements for quotation.
Q6: Are routine factory tests performed before shipment?
Routine factory tests and specific certification details are subject to confirmation. Standard compliance aligns with IEC specifications for 0.66kV indoor current transformers. Contact our sales team for the detailed test report format.
Q7: What is the typical application for this LQZJ-0.66 series?
This 0.66kV indoor epoxy resin cast current transformer is primarily used for current measurement in low-voltage switchgear. It operates effectively in pollution degree 2 environments. Contact us for application-specific selection guides.