benlong 
MCB manual thermal trip calibration bench
Manual MCB thermal trip calibration bench for short‑time delay testing. Adjustable overload current (0‑125A), digital timer (±0.1%), stable current source. Portable, affordable, ideal for small‑batch production, lab, and field use. Customizable current range and clamps.
MCB Manual Short‑Time Delay Thermal Trip Calibration Bench
The MCCB Manual Thermal Trip Calibration Test Bench is an instrument developed to perform long delays on Miniature Circuit Breakers (‘MCB’) by evaluating and measuring their short‐term delay via a manual method. The MCB will demonstrate delay trip characteristics through user‐defined test parameters of overload current and time duration in a controlled overload environment or condition. Test parameters are displayed digitally, maintaining a clean test channel, with an interface providing accurate measurements relating to the time duration of short term delay. The fabrication of this MCB Manual Calibration Test Bench is durable and easy to operate; thus being ideal as an analysis and inspection laboratory for small production output. Therefore, certifying the MCB meets the standards of short-term delay testing per IEC 60898‐1 thus making it an independent, objective manner of confirming that MCB will operate safely and correctly under the designed conditions.
This bench allows you to adjust the current manually (or digitally) with either a variable resistor or encoder, gives you a display of real time trip time on the LCD display, and optionally also has an audible alarm to indicate if the test passed or failed. The bench is designed to be compact, easy to transport, and suitable to be used in the field as well as in research & development laboratories (R&D), and for low volume production lines where flexibility is more important than fully automated testing. Common uses for the bench would be performing a batch sampling or verifying prototypes, and maintaining the short time trip characteristics of MCBs.
Standard delivery: 30-45 days | Manual current setting | Digital timer ±0.1%
What is an MCB Manual Thermal Trip Calibration Bench?
The MCB Manual Thermal Trip Calibration Test Bench is a basic testing apparatus used to verify the short time delay (thermal overload) characteristic of miniature circuit breakers. The MCB manual thermal trip calibration test bench is fundamentally different from automatic test benches in that the MCB manual thermal trip calibration test bench requires the operator to manually set the test current (for example, using a dial or by entering it digitally), and to observe the trip time on a digital timer. It is designed to be used for low volume applications and therefore requires that the test bench be flexible, easy to use, and cost effective. The MCB manual thermal trip calibration test bench includes a stable constant current source, a digital timer with an accuracy of ±0.1%, and a simple fixture for connecting the MCB. The MCB manual thermal trip calibration test bench is commonly used in small laboratories, field maintenance, and as a backup for production lines. As a non-standard custom solution, we can customize the current range, fixture, and timer to meet your specific MCB ratings and testing requirements.
Potentiometer or digital encoder for precise overload current selection.
Clear LED or LCD display, accuracy ±0.1%, range up to 99 hours.
Constant current source with low drift (<2% over 8 hours).
Lightweight design for field service or lab bench use.
Key Features & Calibration Process
Technical Specifications
| Test current range | 0 – 125A (customizable up to 200A) |
|---|---|
| Current setting | Manual potentiometer or digital encoder (step 0.1A) |
| Timing range | 0.1s – 9999s (or up to 99 hours) |
| Timing accuracy | ±0.1% of reading |
| Display | LED or LCD digital timer, current readout optional |
| Test modes | No‑trip check (100% In) and trip test (135% In or user‑set) |
| Fixture type | Manual screw‑type clamps for 1P/2P/3P/4P MCBs |
| Power supply | 220V ±10% 50Hz |
| Dimensions (L×W×H) | Approx. 400mm × 350mm × 200mm (portable) |
| Weight | Approx. 15kg |
Core Technical Advantages
Simple manual operation – no training required
Technicians can use this bench without having prior experience using automated equipment. Simply turn the dial to the current value and push the Start button; the time it takes to complete the task will be displayed as well as whether the trip timing met the pass/fail criteria on the timer (or an additional buzzer that could be added as an option).
Stable current for repeatable results
The constant current source has a high level of accuracy and will keep the set current at ±2% during long duration tests. The waveform has very little distortion (
Versatile fixture for multiple MCB types
Manual clamps allow for changes in MCB size (1P/2P/3P/4P) without requiring new tooling. Adjustable contacts allow you to accommodate different terminal spacing (17.5 mm – 25 mm).
Affordable & portable for field use
The bench weighs only 15 kilograms and can be transported to job sites easily. An optional carrying case and battery-operated timer are available for off-grid testing of the bench.
Customer Success Story – Electrical Contractor
A contractor wanted to test short-term delay trips on mini circuit (MCB) in the field after lightning strikes. The customer needed a portable battery-operated bench. Benlong supplied the customer with a manual thermal trip test bench for calibration and had an internally mounted rechargeable battery pack, both designed for use in a rugged way. The results of these benches after six (6) months were:
The bench paid for itself in 4 months by preventing nuisance trips and unnecessary replacements.
Applications and Integration
Custom Engineering & Delivery
Request a Custom Manual Calibration Bench Quote
Please provide your MCB rating, test current range, and any portability requirements. Our engineers will create a simple, reliable manual thermal trip bench for you along with a complete ROI.
I hope the above complies with your request! Best, [Your Name]
WhatsApp: +86 150 5837 0007 | Email: xsb@benlongkj.cn | English & Chinese support
Why Choose Benlong for Manual Calibration Benches?
- 15+ years designing MCB test equipment for professional and field use
- Simple, rugged, and cost‑effective designs
- Stable current source with long‑term reliability
- Portable options for on‑site testing
- Global service and spare parts support
Standard Bench Includes
(0-125A) steady state current supply, digitally timed to within plus or minus 0.1%, electrically adjustable via an adjustment knob, includes test lead with universal clamp type connectors, includes overload fuse, includes operators manual, calibrated at time of certification, includes one-year warranty.
Frequently Asked Questions
Thermal trip tests usually have short time delays and are required to provide overload currents at current levels of 1.45x In, measuring the current-tripping time from seconds to minutes. Long time delay tests (e.g. 1 Hour @ 100% In) would be done on the bench type for type tests. This bench was designed to perform short time delay verifying tests.
Sure. All of the universal clamps will work with 1 pole, 2 pole, 3 pole and 4 pole circuit breakers. If you are testing multi-pole circuit breakers, you will need to test each pole separately (in a sequence).
The front panel has an analog or digital meter that will show you the value of your actual current with a manual potentiometer dial or a digital encoder enabling you to increase or decrease the current by turning the knob until you have the required amount of current.
The current supply has short circuit protection using a breaker or fuse inside. There is also overheating shut off built in.
The purpose of this bench is for MCB thermal (overload) testing only. There is a separate RCBO test bench with a demagnetisation function available for testing RCBOs for residual current.
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