Schneider Electric 31112 500 A 3-Pole ComPacT INS Switch

31112: ComPacT INS500, 500 A, 3 poles

The 31112 is a Schneider Electric ComPacT INS switch-disconnector, listed in its datasheet as the switch-disconnector Compact INS500 – 500 A – 3 poles, rated 500 A with 3 poles. In plain terms it is a heavy-duty manual load-break switch that makes and breaks load current and isolates, but contains no tripping element, so it never replaces the circuit breaker upstream. Seven Star LLC supplies the 31112 in Oman and the GCC as an independent supplier based in Muscat.

In the model name, INS is the ComPacT switch-disconnector family and the number is the thermal rating in amperes. For this reference that gives INS500, 500 A and 3 poles. It has a black direct front rotary handle and front connections. This is the entry point of the range: the 500 A rating in the compact 185 mm wide body. It suits main isolators on mid-size distribution boards, the incoming switch of a motor control centre section, and plant that is fed from a single transformer feeder of moderate size.

Technical specifications of the 31112

Duty categories and short-circuit data of the 31112

For this reference the datasheet gives the rated operational current as 500 A in AC-22A and AC-23A at every voltage band from 220/240 V up to 660/690 V. AC-21A means resistive loads, AC-22A mixed resistive and inductive loads, and AC-23A motors and other highly inductive loads; read the AC-23A line when a motor or transformer sits behind the switch.

On DC the datasheet lists DC-22A and DC-23A at 500 A, 125 V DC, two poles in series; a rating given with poles in series is valid only for that wiring. Against the two 630 A references that share this frame, the 500 A switch is the only one without a DC-23B figure, and its DC ratings stop at 500 A.

The AC-23 motor-switching capacity is given per voltage band: 132 kW at 220/240 V; 250 kW at 380/415 V; 250 kW at 440 V; 355 kW at 500/525 V; 500 kW at 660/690 V. The 31112 makes 50 kA as a switch-disconnector alone and 330 kA with an upstream circuit breaker (690 V AC), carries 11.5 kA for 3 s, 20 kA for 1 s, 4.9 kA for 20 s and 4 kA for 30 s for the short-time withstand periods, and has insulation voltage 800 V AC 50/60 Hz with 8 kV impulse withstand. Because the same body also carries the 630 A versions, the 500 A figure is a rating, not a size limit: confirm the real load current and the upstream protection, then decide whether 500 A leaves enough margin or whether the 630 A sibling is the safer purchase.

ComPacT INS references compared with the 31112

Frame width stays at 185 mm up to 630 A and then jumps to 340 mm (three poles) or 410 mm (four poles). Compare the 31112 with its neighbours:

Frame, handle and mounting of the 31112

The 31112 measures 205 mm high, 185 mm wide and 120 mm deep, at a connection pitch of 45 mm, and weighs 4.6 kg. It is fixed-mounted on a rail or a plate, with front connection top and bottom. The handle is a black front rotary handle fixed directly on the device, and a contact position indicator shows whether the switch is open or closed. The datasheet states no visible break.

Mechanical durability is 10000 cycles, and the electrical durability is AC-22A and AC-23A: 1500 cycles at 440, 500 and 690 V AC. The mechanical figure applies to operation without load; the electrical figure is the life when the switch actually breaks current.

Installation, commissioning and care of the 31112

Mount the 31112 on its rail or plate and make the front busbar or cable connections without letting weight hang on the terminals. Torque them to the figures in the installation sheet.

Maintenance is mostly visual and thermal. Check terminals for discolouration and re-check torque after the first weeks of service. In an installation with frequent load switching, count operations against the electrical durability of AC-22A and AC-23A: 1500 cycles at 440, 500 and 690 V AC and plan replacement before that number is reached. IP40 applies to the device itself, so the enclosure must supply any extra protection.

Selection checklist for the 31112

Before ordering the 31112, collect the following.

• Rated current: 500 A, with the operational current in the category that matches the load (AC-21A, AC-22A, AC-23A or a DC category).
• Poles: 3, and whether the neutral must be switched.
• Voltage: up to 690 V AC, and 125 V DC with two poles in series for DC.
• Prospective short-circuit current compared with the 50 kA making capacity alone and the upstream breaker.
• Space: 205 x 185 x 120 mm, 4.6 kg, 45 mm pitch.
• Cabinet temperature compared with -25 to 70 °C operation.

Where the 31112 fits in Oman and the GCC

In Oman and the GCC, switch-disconnectors of this class are found in main low-voltage switchboards of oil and gas facilities, power stations, desalination and water treatment plants, petrochemical units and large commercial buildings. They serve as incoming isolators, bus-section switches and as the isolating point next to large breakers when maintenance staff need a clear off position.

Heat, dust and humidity are the usual stress factors, so compare the cabinet temperature with the datasheet range. The 31112 is manual and must always be combined with a breaker or fuse sized for the network fault level.

Documents and quotation

A datasheet for this product is attached on this page. It carries the electrical, mechanical and environmental data summarised above, so check it against your own single-line diagram or panel drawing before ordering.

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 operates separately from the manufacturer.