NMX‑CRT‑4 / Rev 00 / switchgear protection / IEC 60947 · 60255 2026 · Product Page

NMX-CRT-4 · ENGINEERED TO ORDER — CIRCUIT-BREAKER & RELAY TEST BENCH

Prove it trips when it must.

Name: Circuit-Breaker & Relay Test Bench
Brand: Neometrix

The bench that proves the protection works before it has to. A circuit breaker or protective relay sits idle for years, then must trip in a fault — and if it does not, the damage is done. This bench verifies it beforehand: it injects a controlled fault and measures the response. Primary high-current injection drives current through a breaker to check its tripping characteristic; a secondary-injection test set verifies a relay's pickup and timing; timing and contact-resistance measurement confirm the mechanism. We build the engineered bench around it — the high-current injection source, the fixturing, the console, the measurement integration and the automation; the specialist relay test set and micro-ohmmeter are bought in. Engineered to order — no specific delivered system is claimed.

Enquire — switchgear test bench Capability sheet (PDF)

Illustrative image, not a delivered installation — an electrical switchgear test bench: a control console with instrument panels beside a large primary-current injection unit with heavy copper output studs and cables connected to a moulded-case circuit breaker clamped on a test bed, no text, no markings and no people

Fig · 01 A switchgear test bench — a primary-current injection unit driving a fault current through a breaker on the test bed — illustrative, not a delivered installation

Tests

breakers + relaysMCB to numerical relay

Injects

current + voltageprimary + secondary

Measures

trip time+ contact resistance

Standard

IEC 60947 / 60255+ 62271

Goal

proven to tripbefore the fault

ISO 9001 / 14001 Engineered to order Electrical test benches IEC 60947 / 60255 Noida · India

Overview

The protection sits idle, then must act.

A circuit breaker or a protective relay spends almost its whole life doing nothing — and then, in a fault, it has milliseconds to trip and clear the circuit. If it is mis-set, mechanically sluggish, or its contacts have degraded, it fails exactly when everything depends on it, and the fault escalates. You cannot wait for a real fault to find out. So you inject a controlled fault on a test bench and confirm the device operates to its characteristic — the right trip, at the right current, in the right time — before it is trusted to protect a live circuit.

Illustrative image, not a delivered installation — a protective-relay test bench: a numerical protection relay in a panel connected by coloured test leads to a portable secondary-injection test set with rows of output terminals and a controller, matte and unmarked, no text and no people

Fig · 02 A protective-relay test bench — secondary injection verifies a relay's pickup, timing and protection functions — illustrative, not a delivered installation

Inject the fault, measure the response. For a circuit breaker, primary high-current injection drives a large current through it to trace its time-current tripping curve (thermal and magnetic trip); for a relay, a secondary-injection test set applies precise current and voltage to check pickup, dropout and operating time against the setting.

Test the mechanism, not just the trip. A breaker is also a mechanism: timing (opening and closing time, pole discrepancy), contact resistance (a micro-ohm measurement that reveals eroded or loose contacts), insulation resistance, and the trip and close coils and spring-charge motor. A modern numerical relay is verified by three-phase injection across its protection functions.

The bench is the engineering. The specialist relay test set and the precision micro-ohmmeter are bought-in instruments. What makes them a usable, safe, repeatable bench is the engineering around them: the high-current injection source (transformer, variac, heavy busbar), the fixturing for the device, the control console and routing, the measurement integration, the automation and reporting, and the safety interlocks — our competence.

Protection you have never tested is protection you only hope works. The bench turns a hope into a measured, documented fact — the breaker trips at the right current, the relay picks up in the right time — before a real fault ever asks the question.

Protection Tested, Not Hoped

Verify it before the fault

A breaker or relay sits idle for years, then must trip in milliseconds. If it fails, the fault escalates. This bench injects a controlled fault and proves the device operates — before it is trusted with a live circuit.

Inject the Fault, Measure the Response

Trip curve, pickup, timing

Primary high-current injection traces a breaker's time-current trip curve; a secondary-injection test set verifies a relay's pickup and time; contact resistance and timing confirm the mechanism.

The Bench Is Ours

Instruments bought-in; bench built

The specialist relay test set and micro-ohmmeter are bought-in; Neometrix engineers the high-current injection source, the fixturing, the console, the measurement integration, the automation and the safety — electrical test-bench competence.

Architecture

Inject, measure, verify.

The schematic shows the test logic — set up the device, inject the fault, measure the response, and pass or fail it to the characteristic — and the engineered bench that does it. The detail panel covers the two tests and the standards.

FIG · 03CRT ARCHITECTURE · INJECT / MEASURE / VERIFY · BREAKER + RELAY · IEC 60947 / 60255

Fig · 03 Inject a controlled fault and measure the response, then pass or fail the device to its characteristic — breakers by high-current injection, relays by secondary injection

Arc · 01

Set Up the Device

Fixture and connect the device under test, whether a moulded-case or air circuit breaker on the test bed or a protective relay wired to the injection set; the routing selects the test.

Arc · 02

Inject the Fault

Primary high-current injection through a breaker to trace its trip curve, secondary injection into a trip unit or relay, or three-phase injection to exercise a numerical relay's protection functions.

Arc · 03

Measure the Response

Trip time, pickup and dropout, contact resistance (micro-ohm), coil operation and insulation — the numbers that say whether the protection is fit.

Arc · 04

Evaluate & Report

The response is compared to the device's characteristic and the standard, pass or fail, with an automated, traceable test report — the record a QA or commissioning file needs.

Have a circuit-breaker, relay or switchgear test-bench requirement? Send the device class and the standard — a clause-by-clause compliance matrix within two working days · [email protected]

Send tender spec

Specifications

Reference bench, built to the switchgear.

The parameters below describe a reference bench. The injection current, the voltage ranges, the relay test set, the timing resolution and the automation all follow from the switchgear class — LV MCB, MCCB and ACB, MV switchgear, or protective relays — and the standard it is tested to.

Illustrative image, not a delivered installation — a high-current primary-injection unit: a large step-down transformer and variac cabinet with heavy copper output busbars and thick flexible cables looping to a moulded-case circuit breaker clamped in a test fixture, matte grey steel and copper, no text and no people

Fig · 04 The high-current primary-injection unit — a transformer and variac driving fault-level current through a breaker to trace its trip curve — illustrative, not a delivered installation

Where switchgear testing goes wrong

In the setup, the source and the safety, not the pass/fail. An under-rated injection source cannot reach the breaker's magnetic-trip current; a poor connection adds resistance that corrupts the reading; an uncalibrated test set mis-judges a relay's pickup; and high-current or high-voltage testing without proper guarding and interlocks is a safety failure regardless of the result.

That is why the injection source is sized to the device, the connections are low-resistance and repeatable, the instruments are calibrated, and the bench is guarded and interlocked. The measure of a test bench is that its pass means the protection really will operate — and its result is traceable.

Full specification — expand

System	Circuit-breaker & relay test bench — engineered & integrated: high-current primary-injection source, secondary & numerical-relay test-set integration, timing & contact-resistance measurement, fixturing, control console, automation & reporting
Breaker Testing	Time-current tripping characteristic (primary injection), secondary injection, opening/closing timing, pole discrepancy, contact resistance (micro-ohm), insulation resistance, trip/close coil & charging motor — MCB / MCCB / ACB
Relay Testing	Secondary injection — pickup, dropout, operating time & characteristic; numerical / microprocessor relay testing by three-phase current & voltage injection across protection functions (overcurrent, earth-fault, differential, distance); coordination
Injection Source	High-current primary-injection source (step-down transformer, variac / thyristor control, heavy busbar & contacts, shunt) — sized to the device; secondary AC/DC injection
Measurement	Trip / operating time, pickup / dropout, contact resistance, coil current, insulation resistance — integrated & recorded
Automation & Safety	PLC / PC control, test sequencing, guarded enclosure, interlocks, emergency stop; automated evaluation & test report
Standards	IEC / IS 60947 (LV switchgear); IEC 62271 (HV switchgear); IEC 60255 (measuring relays & protection) — tested & evaluated to the cited code
Sourcing	The protective-relay secondary-injection test set, the numerical-relay test set & the precision micro-ohmmeter are bought-in specialist instruments; Neometrix engineers & integrates the bench, injection source, fixturing, console, measurement, automation & safety
Status	Engineered to order · configured to the switchgear class & standard · quoted across switchgear & relay test requirements · no specific delivered system is claimed on this page

PDF · 1 page

Circuit-Breaker & Relay Test Bench — Capability Sheet

Tender Response

Send your device class & standard — compliance matrix in two working days

Variants

One bench, breaker to relay.

Tenders call it a circuit-breaker test bench, a relay test bench, switchgear test equipment or an MCB test bench. The principle — inject a controlled fault, measure the response, verify to the standard — is common; the bench is configured to the device and the throughput.

Var · 01

LV Breaker Test Bench

MCB / MCCB / ACB: primary high-current injection for the trip characteristic, plus timing, contact resistance and coil testing — the switchgear-manufacturer and QA workhorse.

Var · 02

Protective-Relay Test Bench

Secondary injection and numerical-relay testing (three-phase current and voltage across protection functions) — for utility and industrial protection.

Var · 03

Contact-Resistance & Timing Set

Micro-ohm contact resistance and timing / travel analysis for breakers — the mechanism-condition set, in maintenance as well as manufacture.

Var · 04

Automated Switchgear Test Line

A sequenced, automated routine / production-test bench with recipe and reporting — for volume MCB / MCCB quality assurance.

Applications

Where it verifies.

Wherever switchgear protection must be proven — in manufacture, at commissioning, and in service.

A · 01Switchgear-manufacturer routine & type test

A · 02Utility substation relay testing & commissioning

A · 03Industrial-plant protection maintenance

A · 04MCB / MCCB production quality-assurance test

A · 05Test-house & NABL switchgear testing

A · 06Railway & traction protection testing

FAQ

Common questions.

Plain-language answers from the engineering team.

Q · 01 What is a circuit-breaker and relay test bench, and why does it matter?

It is functional test equipment that proves electrical protection actually works — that a circuit breaker or protective relay will trip correctly when a fault occurs. It matters because protection is the one part of an electrical system that spends its entire life doing nothing visible, and then, in a fault, has milliseconds to act. A breaker that is mis-set, mechanically sluggish or has eroded contacts, or a relay that is wrongly configured, will fail at exactly the moment everything depends on it — and a fault that should have been cleared in a fraction of a second instead escalates into equipment damage, fire or a wider outage. You cannot discover that by waiting for a real fault. So the device is taken to a bench, a controlled fault is injected, and its response is measured against its intended characteristic: does the breaker trip at the right current and in the right time, does the relay pick up at the right setting? Only then is it trusted to protect a live circuit. It is the test behind every switchgear factory's quality release, every substation commissioning, and every protection-maintenance visit.

Q · 02 What do you test on a circuit breaker?

Several things, because a breaker is both a protective device and a mechanism. First, the tripping characteristic: by primary injection — driving a large, controlled current through the breaker — you confirm it trips at the right current and in the right time, across both its thermal (overload) and magnetic (short-circuit) regions, tracing the time-current curve. Second, the timing: the opening and closing times, and for multi-pole breakers the discrepancy between poles. Third, the contact resistance — a micro-ohm measurement across the closed contacts that reveals erosion, pitting or a loose joint that would overheat in service. Fourth, insulation resistance between poles and to earth. And fifth, the operating mechanism — the trip and close coils and the spring-charging motor. Together these say whether the breaker will both carry normal current safely and interrupt a fault reliably. The bench provides the high-current source, the fixturing, the timing and the measurement to do all of it in one place.

Q · 03 How do you test a protective relay?

By injection — feeding the relay controlled electrical inputs that simulate a fault and checking how it responds. In secondary injection, a test set applies precise current and voltage to the relay's inputs and measures its pickup (the level at which it operates), its dropout, and its operating time, and traces its characteristic curve against the setting. A modern numerical (microprocessor) relay houses many protection functions at once — overcurrent, earth-fault, differential, distance, and more — so it is tested with a three-phase current-and-voltage injection set that can reproduce realistic fault conditions and verify each function, its timing and its logic. The bench also supports coordination checks — confirming that, for a fault at a given point, the correct relay operates first and the ones upstream hold, so only the smallest necessary section is disconnected. The specialist injection test set is a bought-in instrument; the bench integrates it with the fixturing, routing, control and reporting that make relay testing systematic.

Q · 04 What do you build, and what is bought-in?

The precision test instruments are specialist bought-in items: the protective-relay secondary-injection and numerical-relay test sets, and the precision micro-ohmmeter and timing analyser. What Neometrix engineers, builds and integrates is the bench that turns those instruments into a complete, safe, repeatable test capability: the high-current primary-injection source (the step-down transformer, the variac or thyristor control, the heavy busbar and contacts, the shunt) — which is a genuine fabricated electrical rig, not an off-the-shelf box; the fixturing that holds and connects the device under test; the control console and routing; the measurement integration; the automation, sequencing and reporting; and the guarded, interlocked enclosure and safety chain. This is our competence — the same electrical, test-rig, controls and fabrication engineering behind our high-voltage, EMC and power-electronics test lines. So the specialist injection instruments come from the instrument specialists, and the engineered bench that makes them a working switchgear-test line is ours. To be plain about status: this is offered engineered-to-order and quoted against switchgear and relay test requirements; no specific delivered system is claimed on this page.

Q · 05 How is this different from the high-voltage (dielectric) test bench?

They ask different questions of the switchgear. A high-voltage dielectric bench proves that the insulation holds — it applies a high AC, DC or impulse voltage and confirms the device withstands it without breaking down, and measures partial discharge; it is a test of insulation integrity. This circuit-breaker and relay bench proves that the protection operates — it injects a fault-level current or a relay input and confirms the device trips or picks up correctly, at the right level and in the right time; it is a test of functional protection. One asks ‘will it hold off the voltage it normally stands against?’, the other asks ‘will it act when a fault arrives?’. Both matter, and a switchgear test facility often has both, but they are different benches with different sources, instruments and standards — dielectric-withstand testing to the insulation clauses, functional testing to IEC 60947 and IEC 60255. We build both; this page is the functional-protection bench.

Q · 06 Which standards do you work to?

The functional testing of switchgear and protection is governed by well-defined standards, and the bench is built to test and evaluate against them. For low-voltage switchgear — MCBs, MCCBs and air circuit breakers — the family is IEC / IS 60947 (and IS 8828 / IEC 60898 for household MCBs), which define the tripping characteristics, timing and test methods. For high-voltage switchgear, IEC 62271 applies. For protective relays, IEC 60255 (measuring relays and protection equipment) defines accuracy, timing and test conditions. In practice a requirement names the device class, the characteristic and the standard, and we engineer the bench — the injection ranges, the timing resolution, the measurement and the reporting — to test and accept the device to exactly that, set out clause by clause in the compliance matrix. The point of the standard is that a ‘pass’ on the bench means the device will behave the same way, to the same limits, in the field.

↗

The electrical test line from Neometrix.

The high-voltage, EMC and power-electronics test systems alongside it — engineered at our Noida facility.

↗ HV / Dielectric

High-Voltage Test Bench

Proving the insulation holds — the dielectric-withstand sibling to functional-protection testing.

↗ EMC

EMI / EMC Test Laboratory

Electromagnetic compatibility & immunity — the EMC member of the electrical test-lab house.

↗ Electrical Test

EV Charger Test System

Functional test of power-electronics equipment — the same test-bench-integration engineering.

Browse all Neometrix product lines.

Get a quotation

Send the device
and the standard.

Our projects desk replies within two working days with a clause-by-clause compliance matrix and a budgetary quotation. Write to [email protected] or use the form.

Enquire — switchgear test bench Capability sheet (PDF) +91 7777 876 876

ISO 9001 / 14001 ENGINEERED TO ORDER — CIRCUIT-BREAKER & RELAY TEST BENCH PRIMARY INJECTION · SECONDARY INJECTION · NUMERICAL RELAY · TIMING · CONTACT RESISTANCE · TO IEC 60947 / 60255 ENGINEERED IN NOIDA · INDIA

Prove it trips when it must.

The protection sits idle, then must act.

Verify it before the fault

Trip curve, pickup, timing

Instruments bought-in; bench built

Inject, measure, verify.

Set Up the Device

Inject the Fault

Measure the Response

Evaluate & Report

Reference bench, built to the switchgear.

Where switchgear testing goes wrong

One bench, breaker to relay.

LV Breaker Test Bench

Protective-Relay Test Bench

Contact-Resistance & Timing Set

Automated Switchgear Test Line

Where it verifies.

Common questions.

The electrical test line from Neometrix.

High-Voltage Test Bench

EMI / EMC Test Laboratory

EV Charger Test System

Send the device
and the standard.

Similar Products

Share This Page

Prove it trips when it must.

The protection sits idle, then must act.

Verify it before the fault

Trip curve, pickup, timing

Instruments bought-in; bench built

Inject, measure, verify.

Set Up the Device

Inject the Fault

Measure the Response

Evaluate & Report

Reference bench, built to the switchgear.

Where switchgear testing goes wrong

One bench, breaker to relay.

LV Breaker Test Bench

Protective-Relay Test Bench

Contact-Resistance & Timing Set

Automated Switchgear Test Line

Where it verifies.

Common questions.

The electrical test line from Neometrix.

High-Voltage Test Bench

EMI / EMC Test Laboratory

EV Charger Test System

Send the deviceand the standard.

Similar Products

Share This Page

Send the device
and the standard.