ABB Tmax XT3N 250 3-Pole Moulded Case Circuit Breaker
The XT3N 250 TMD is a fixed, three-pole moulded case circuit breaker from ABB's Tmax XT range, fitted with front terminals and a TMD thermomagnetic release offering an adjustable current setting range of 175-250A. Rated at 690V AC with a short-circuit performance level N, it provides robust protection for main distribution and sub-main applications in commercial and industrial UAE facilities, backed by a wide range of ABB accessories for customisation.
Key Features
- 3-pole fixed MCCB rated at 250A with adjustable TMD thermomagnetic release (175-250A setting range)
- Rated ultimate breaking capacity (Icu) of 36kA at 380-440V AC, suitable for demanding commercial and industrial fault levels
- Front terminal bolt-type connections rated for busbar cross-sections of 85-192 mm²
- High mechanical durability of 25,000 cycles and electrical durability of 8,000 cycles for long service life
- Genuine ABB quality
Technical Specifications
| Specification |
Details |
| Brand |
ABB |
| Model |
XT3N 250 TMD 250-2500 3p F F |
| Poles |
3P |
| Rated Current (In) |
250A |
| Setting Range (Thermomagnetic) |
175-250A |
| Release Type |
TMD (Thermomagnetic) |
| Rated Instantaneous Short-Circuit Setting (Ii) |
2500A |
| Rated Operational Voltage |
690V AC / 500V DC |
| Rated Insulation Voltage (Ui) |
800V |
| Rated Impulse Withstand Voltage (Uimp) |
8 kV |
| Rated Ultimate Breaking Capacity (Icu) |
50kA (220-240V) / 36kA (380-440V) / 5kA (690V) |
| Terminal Connection Type |
Front, Bolt Terminal |
| Mounting |
Fixed |
| Current Type |
AC/DC |
| Net Weight |
1.7 kg |
Applications
- Main and sub-main distribution board protection in commercial and industrial UAE buildings
- Transformer and generator protection requiring adjustable thermomagnetic settings
- Power distribution circuit protection in panel builder switchboard assemblies
- Motor and feeder circuit protection where a compact, fixed 250A MCCB is required
FAQ
-
What's the difference between an MCB and an MCCB?
An MCB (miniature circuit breaker) is typically rated up to 100A with a fixed, non-adjustable trip and lower breaking capacity, used for final circuits. An MCCB (moulded case circuit breaker) is built for higher currents and fault levels, and is used for main incomers, sub-mains, and feeder protection where an MCB's rating or breaking capacity would be insufficient.
-
When do I need an MCCB instead of an MCB?
Use an MCCB where the prospective fault current or load current exceeds what an MCB is rated to handle safely — typically at the main incomer or major sub-main level of a commercial or industrial distribution board.
-
Does this MCCB have an adjustable trip setting?
Check the specific trip unit type in the Technical Specifications table above — thermal-magnetic MCCBs may have a fixed or adjustable trip range depending on the model; an electronic trip unit typically offers configurable protection curves.
-
Can I install this myself?
No. MCCBs are installed in distribution boards and panels by a licensed electrician, in line with UAE wiring regulations.
