Schneider Electric 33546 ComPact NS630bN 630 A 3P Breaker

33546: 630 A ComPact NS630bN 3-pole breaker, MicroLogic 5.0

The 33546 is a fixed-mounting Schneider Electric ComPact NS molded-case circuit breaker rated 630 A at 50 °C, listed in the datasheet as: Circuit breaker, ComPact NS630bN, 50kA/415VAC, Micrologic 5.0 trip unit, 630A, fixed, 3 poles 3d. Seven Star LLC supplies it in Oman and the GCC as an independent supplier based in Muscat.

The device short name in the datasheet is Compact NS630bN. In this naming the digits give the frame current class, and the letter N is the breaking-capacity level: the datasheet’s performance level reads N 50 kA at 415 V AC. The trip unit is MicroLogic 5.0, an LSI electronic unit, and the device has 3 protected poles (3D).

Please note that the datasheet carries a discontinued notice dated 30 Sep 2024. Seven Star LLC can still quote the 33546 where stock or alternatives exist, but availability should be confirmed before it is specified for a new project; for a like-for-like replacement we need the full nameplate of the breaker being replaced.

Technical specifications of the 33546

MicroLogic 5.0 settings on the 33546

The MicroLogic 5.0 is an LSI unit: long-time overload (L), short-time short-circuit (S) and instantaneous short-circuit (I) protection. The added short-time stage is what lets this breaker ride through a brief fault for a chosen time while a downstream breaker clears it, which is the basis of time-delayed selectivity on a distribution board.

Long-time pick-up Ir runs from 0.4 to 1 x In in 9 settings, so on this 33546 (In = 630 A) from 252 A to 630 A. The long-time delay tr is 12.5 to 600 s at 1.5 x Ir, 0.5 to 24 s at 6 x Ir and 0.7 to 16.6 s at 7.2 x Ir, with a 20 minute thermal memory.

The short-time pick-up Isd is adjustable from 1.5 to 10 x Ir in 9 settings, up to 6,300 A at Ir = 630 A (calculated). The short-time delay tsd is 0 to 0.4 s with I²t off and 0.1 to 0.4 s with I²t on. The instantaneous pick-up Ii is 2 to 15 x In, or Off; for this rating that is 1,260 A to 9,450 A when it is in use.

Breaking capacity of the 33546 by voltage

The datasheet lists the following ratings, conforming to IEC 60947-2. Icu is the ultimate breaking capacity; Ics is the rated service breaking capacity.

On this 630 A device the datasheet gives Ics equal to Icu at 220/240, 380/415 and 440 V, and at 500/525 and 660/690 V as well.

Icw is 19.2 kA for 1 s; utilisation category B.

Current rating, poles and heat in the panel for the 33546

At 415 V a three-phase load of 630 A corresponds to roughly 453 kVA (calculated as √3 x 415 V x 630 A; not a datasheet value). The datasheet gives the rated current as 630 A at 50 °C, with the device operating in ambient temperatures up to 70 °C, so in a hot switchroom the loading of the 33546 should be checked against the manufacturer’s derating information rather than assumed to be 630 A.

The 33546 is the three-pole version: 210 mm wide and 14 kg. It protects and switches three phase poles (3D). If the system needs a switched or protected neutral, the four-pole form of the same rating is the alternative; it is 280 mm wide and 18 kg and adds neutral settings.

The datasheet states power losses of 10 W for this device. That heat stays inside the enclosure, so when several breakers sit in one cubicle their dissipation is added to the busbar and cable losses when the cooling or ventilation is sized.

Related ComPact NS references

Seven Star LLC also handles other ComPact NS references. Check poles, trip unit and breaking-capacity level before substituting any of them for the 33546.

33558 is NS1000N with 1000 A instead of 630 A. 33564 is NS1250N with 1250 A instead of 630 A.

Accessories such as release coils, rotary handles and motor mechanisms are separate part numbers; send them with the breaker reference for a complete quotation.

Installing and maintaining the 33546

Before energising, check that the 33546 is mounted on its backplate, that busbars or cable lugs match the 70 mm connection pitch and that the contact surfaces are clean. Then set the trip unit: Ir first, then tr, then the short-circuit thresholds. Record the settings on the single-line diagram. Because the unit is LSI, the Isd and tsd settings must be coordinated with the downstream breakers, and if Ii is set to Off the short-circuit stage relies on Isd alone.

The trip unit has 4 red LEDs for fault indication and 1 yellow LED for overload, a first diagnosis after a trip. Electrical durability is 2000 cycles at 690 V In; 4000 at 690 V In/2; 5000 at 440 V In; 6000 at 440 V In/2; use it when planning inspection intervals.

With IP40 and IK07 protection and pollution degree 3, the 33546 belongs inside an enclosed switchboard; the stated humidity limit is 0 to 95 %.

Where the 33546 is used in Oman and the GCC

A 630 A rating is the entry point of this frame family and tends to appear on the incomer of a medium workshop board, a chilled-water plant motor control centre, or a feeder from a main LV switchboard to a sub-distribution board in a desalination or water-treatment building. In the Gulf the real constraints are ambient temperature in electrical rooms, dust from desert wind and humidity near the coast, which is why enclosure ventilation and the breaker’s operating ambient of up to 70 °C deserve a check. The MicroLogic 5.0 with its short-time stage gives a selective-capable device for boards with several tiers of protection.

Information to send with an RFQ for the 33546

To quote quickly and correctly, please send:

• Reference 33546 and quantity; also state whether a replacement for an existing device is intended, since the datasheet shows it as discontinued.
• Poles needed (3) and, for a four-pole device, the neutral protection setting expected.
• System voltage, available fault level at the board and the intended Icu level (N).
• Trip unit required (MicroLogic 5.0) and whether the settings will be supplied by the protection study.
• Control type (toggle or rotary handle) and any accessories required.
• Delivery location in Oman or the GCC, required documents and target date.

Documents and quotation

The official English datasheet for the 33546 is attached on this page. It lists the electrical data, trip-unit settings, dimensions and environmental information used above, and carries the discontinued notice mentioned earlier.

To request a quotation, send the part number 33546, the quantity and the delivery location. Seven Star LLC is an independent supplier in Muscat and quotes according to current availability.