Schneider Electric EZC400N3400N EZC400N 400A 3P MCCB

EZC400N3400N: 400 A three-pole Easypact EZC400N breaker

The EZC400N3400N is a Schneider Electric Easypact EZC400N moulded case circuit breaker, three-pole, with a fixed thermal-magnetic TM-D trip unit. Seven Star LLC supplies the EZC400N3400N in Oman and the GCC as an independent supplier based in Muscat.

How to read EZC400N3400N: EZC400 is the frame, N marks the standard N breaking class, the digit 3 is the number of poles, and 400 is the rated current in amperes. The digits 400 at the end of the reference are the current rating: the datasheet lists [In] as 400 A at 40 °C and the thermal-magnetic trip unit rating as 400 A at 50 °C. A trailing letter N follows the rating in this reference (EZC400N3400N); the datasheet does not explain it, so treat it as part of the identifier rather than a variant you can drop.

The datasheet title describes the breaker as 3 poles, 3d, and lists the protected poles as 3t, so every phase is protected by the trip unit. There is no neutral pole to switch on this version; if your system needs a switched neutral, look at the four-pole sibling of the same frame.

Information to send with an RFQ for the EZC400N3400N

A short list of facts lets us confirm the EZC400N3400N quickly and avoid ordering the wrong class or rating.

• Part number EZC400N3400N, quantity and required delivery time.
• System voltage, frequency and earthing arrangement.
• Calculated prospective short-circuit current at the board.
• Load current, cable size and number of poles needed.
• Board maker, enclosure type and site ambient temperature.
• Photo of the nameplate if you are replacing an existing breaker.

EZC400N3400N technical specifications

How this breaker compares with its siblings

The table compares the EZC400N3400N with references of the same frame group that Seven Star LLC can quote. These are datasheet values only; other ratings and frames exist.

Within one frame the case dimensions are the same from rating to rating, but a change of class or frame needs a check of the busbar connection and the door cut-out. Keep the full reference, including its trailing letter, on every order.

Selection checklist before ordering

The EZC400N3400N is typically specified for a 400 A main incomer or a large plant feeder. Before you order, run through these points.

• Design current and cable: the 400 A trip rating must sit above the design current and below the cable’s current-carrying capacity at site temperature.
• Fault level: compare the Icu at your system voltage (36 kA at 400/415 V AC) with the calculated prospective short-circuit current, and keep the Ics in mind for the duty you expect.
• Number of poles: 3P on this reference. A separate neutral link or a four-pole version is needed where the neutral must be switched.
• Short-circuit trip: the datasheet lists a magnetic tripping current of 5000 A, and the setting is fixed.
• Space: allow 255 mm (H) x 140 mm (W) x 110 mm (D) and a connection pitch of 44 mm.
• Supply type: the datasheet lists AC, with a rated operational voltage of 440 V AC 50/60 Hz.

Installation, commissioning and maintenance

Mount the EZC400N3400N on a rigid backplate; the datasheet lists a fixed mounting mode on a backplate with front connections on both the supply and the load side.

Make the connections to lugs or bars that suit the 44 mm pitch and follow the torque values in the installation sheet. After energising, check the handle and the terminal temperature under load, because a loose connection is the usual cause of a hot spot or nuisance trip.

The trip unit has no setting to adjust, so commissioning is verification. Exercise the handle now and then and inspect the case and terminals; a breaker that has cleared a fault near its Icu should be inspected or replaced. Durability in the datasheet: 10000 cycles mechanical, Category A: 4000 cycles 415 V AC 50/60 Hz electrical.

Breaking capacity by voltage: Icu and Ics in the datasheet

Breaking capacity is the figure that decides whether a breaker may sit at a given point in the network. Icu is the ultimate breaking capacity, the highest fault current the breaker can interrupt, after which it may no longer be fit for service. Ics is the service breaking capacity, a fraction of Icu that the breaker can interrupt and still carry on working. The datasheet of the EZC400N3400N gives both, by voltage, as follows.

At the usual 400/415 V AC level the EZC400N3400N is listed with an Icu of 36 kA. That is the standard class and is enough for most commercial and light-industrial boards; verify it against the calculated fault current at the busbar, not against the transformer rating alone.

Where the EZC400N3400N is used in Oman and the GCC

Easypact EZC breakers are aimed at distribution boards. In Oman and across the GCC that means commercial buildings, hotels, villas and compounds, workshops, warehouses and the utilities of small industrial sites, where moulded case breakers protect feeders between a main board and the floor, plant or pump boards. The EZC400N3400N is typically specified for a 400 A main incomer or a large plant feeder.

The datasheet gives an operating range of -25…70 °C and a storage range of -35…85 °C with IP20 protection, so the breaker belongs in an enclosure. Panels in direct sun, uncooled plant rooms and humid coastal sites run hotter than ambient inside, so allow for the internal temperature when you load the breaker close to its rating.

Documents and quotation

A datasheet for the EZC400N3400N is attached on this page. It lists the ratings and dimensions summarised above and is the document to check against your drawings and load calculations.

Send us the part number, quantity and application and we will confirm availability and a quotation. Seven Star LLC is an independent supplier in Muscat and is not affiliated with the manufacturer.