Verifying short-circuit protection in 500 or 690 V industrial networks takes a loop impedance meter whose voltage range reaches 750 V phase to phase, which few meters cover. The AMZC-305 measures ZL-PE, ZL-N and ZL-L from 0.13 to 1999 Ω per IEC 61557 with 0.01 Ω resolution in eight rated networks, from 110/190 V to 400/690 V, with a 100 to 750 V operating range for ZL-L and a test current of up to 36.7 A at 690 V; it calculates the short-circuit current up to 69.0 kA, measures without tripping RCDs from 0.43 Ω and stores 990 memory cells downloaded over USB.
AMZC-305 key data
- Loop impedance: ZL-PE, ZL-N and ZL-L from 0.13 to 1999 Ω per IEC 61557 (1.2 m leads), 0.01 Ω resolution, ±(5% m.v. + 3 digits) up to 19.99 Ω and ±(4% m.v. + 3 digits) above.
- Networks: 110/190, 115/200, 127/220, 220/380, 230/400, 240/415, 290/500 and 400/690 V; the AMZC-305 operates from 100 to 440 V for ZL-PE and ZL-N and from 100 to 750 V for ZL-L, at 45-65 Hz.
- Test current: a maximum of 36.7 A (10 ms) at 690 V, 24.5 A at 230 V, 21.3 A at 400 V and 12.2 A at 115 V.
- No RCD tripping: ZL-PE RCD mode from 0.43 Ω, without tripping RCDs of IΔn ≥ 30 mA, from 100 to 440 V and with ±(6% m.v. + 10 digits) up to 19.99 Ω.
- Short-circuit current: calculated from ZS and displayed from 0.055 A to 69.0 kA (40.0 kA in RCD mode), with RS and XS for ZS < 200 Ω.
- Voltage: 0 to 750 V, with 0.1 V resolution and ±(2% m.v. + 4 digits) up to 249.9 V.
- Memory and power: the AMZC-305 stores 990 cells (3500 records) and downloads them over USB; four AA batteries, more than 3000 measurements.
- Safety: CAT IV 600 V with double insulation, IP54, 0 to +45 °C, 260 × 190 × 60 mm and about 2.2 kg.
Advantages
Eight rated networks, one meter
It measures in 110/190, 115/200, 127/220, 220/380, 230/400, 240/415, 290/500 and 400/690 V networks, automatically distinguishing phase from line voltage, with ZL-L up to 750 V.
High current for firm readings
The high-current measurement of up to 36.7 A (10 ms at 690 V) yields readings from 0.13 to 1999 Ω per IEC 61557 with ±(5% m.v. + 3 digits) in the low range, with the R and X components and the short-circuit current calculation.
RCDs without tripping
The ZL-PE RCD mode measures from 0.43 Ω without tripping RCDs above 30 mA, in networks from 100 to 440 V and also with the L and N conductors swapped.
Voltage up to 750 V
The built-in voltmeter reads from 0 to 750 V with 0.1 V resolution up to 250 V and an overvoltage alarm, available in every loop function.
Applications
- Verification of short-circuit protection in 500 and 690 V industrial networks.
- Low-voltage installations in housing, offices and workshops.
- Measurements at socket outlets with the UNI-Schuko adapter.
About the product
The AMZC-305 is a loop impedance meter designed for those who work across networks of different voltages: from the 110/190 V of some industrial plants to the 400/690 V of heavy industry. The contact electrode verifies the connection of the PE terminal, measurement is possible with L and N swapped and the working frequency covers 45 to 65 Hz.
With double insulation per IEC 61010-1, a CAT IV 600 V (CAT III 1000 V) category and an IP54 housing, it runs on four AA alkaline batteries or accumulators and switches off automatically after 120 seconds of inactivity. Its 260 × 190 × 60 mm and 2.2 kg include an LED-backlit segment display.
Available accessories: 1.2 m banana test leads (red, blue and yellow), pin probes, K02 crocodile clips, L4 carrying case, USB cable, straps, batteries and a calibration certificate; optionally the WS-05 UNI-Schuko adapter, the WS-01 probe with START button, AGT three-phase adapters from 16 to 63 A and 5, 10 and 20 m leads.
Technical specifications
| Loop impedance | ZL-PE, ZL-N, ZL-L: 0.13…1999 Ω per IEC 61557 |
| Supported networks | From 110/190 V to 400/690 V (100…750 V range); 45…65 Hz |
| Measuring current | High current, max. 36.7 A (10 ms) at 690 V |
| No-trip mode (RCD) | From 0.43 Ω without tripping RCDs >30 mA |
| Voltage measurement | 0…750 V; 0.1 V resolution up to 250 V |
| Memory and interface | 990 cells (3500 records); USB |
| Power supply | 4 AA batteries or accumulators; >3000 measurements |
| Safety | CAT IV 600 V (CAT III 1000 V); IP54 |
| Loop accuracy | ±(5% m.v. + 3 digits) up to 19.99 Ω; ±(4% m.v. + 3 digits) above |
| Short-circuit current | Calculated: 0.055 A…69.0 kA (RCD mode: up to 40.0 kA); RS and XS components |
| Environment, dimensions and weight | 0…+45 °C; 260 × 190 × 60 mm; 2.2 kg |
Frequently asked questions
What short-circuit current can the AMZC-305 display?
The AMZC-305 calculates the prospective short-circuit current from the measured impedance and the rated voltage and displays it from 0.055 A to 69.0 kA; in no-trip RCD mode, up to 40.0 kA. Alongside it shows the resistive RS and reactive XS components when ZS is below 200 Ω.
Can it measure with long leads or with a socket adapter?
Yes. The AMZC-305 range per IEC 61557 starts at 0.13 Ω with the 1.2 m leads, 0.17 Ω with 5 m, 0.21 Ω with 10 m, 0.29 Ω with 20 m and 0.19 Ω with the WS-01 and WS-05 adapters; in no-trip mode, from 0.43 Ω with 1.2 m leads.
What sets it apart from other loop meters?
Its network range: it measures from 110/190 V to 400/690 V — working voltages of 100 to 750 V — essential in industry with 500 or 690 V networks.
Can it measure without tripping RCDs?
Yes. The ZL-PE RCD mode measures from 0.43 Ω in circuits with RCDs above 30 mA without causing them to trip.
What accuracy does the loop measurement offer?
±(5% m.v. + 3 digits) up to 19.99 Ω and ±(4% m.v. + 3 digits) above, with 0.01 Ω resolution and short-circuit current calculation.
Does it indicate the loop components?
Yes. Besides the impedance module, it shows the resistive and reactive components and the short-circuit current calculated for the rated voltage.
