Schneider Electric 31331 800 A 4-Pole ComPacT INS Switch

31331: ComPacT INS800, 800 A, 4 poles

The 31331 is a Schneider Electric ComPacT INS switch-disconnector, listed in its datasheet as the switch-disconnector Compact INS800 – 800 A – 4 poles, rated 800 A with 4 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 31331 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 INS800, 800 A and 4 poles. It has a black direct front rotary handle and front connections. The four-pole 800 A device is aimed at larger distribution boards with a switched neutral, and at changeover sets on generators where all four conductors must be opened together.

Technical specifications of the 31331

Duty categories and short-circuit data of the 31331

For this reference the datasheet gives the rated operational current as 800 A in AC-21A, AC-22A and AC-23A across the voltage bands listed. 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-21A, DC-22A and DC-23A at 800 A and 125 V DC with two poles in series; the datasheet also lists the same three categories for four poles in series at 250 V DC; a rating given with poles in series is valid only for that wiring. It is the four-pole twin of the three-pole 800 A reference and shares every electrical figure with it apart from the pole count and the DC series arrangement.

The AC-23 motor-switching capacity is given per voltage band: 250 kW at 220/240 V; 400 kW at 380/400 V; 500 kW at 415 V; 560 kW at 500/525 V; 710 kW at 660/690 V. The 31331 makes 75 kA as a switch-disconnector alone and 330 kA with an upstream circuit breaker (690 V AC), carries 50 kA for 0.5 s, 42 kA for 0.8 s, 35 kA for 1 s, 20 kA for 3 s, 10 kA for 20 s and 8 kA for 30 s for the short-time withstand periods, and has insulation voltage 1000 V AC 50/60 Hz with 12 kV impulse withstand. At 410 mm wide and 18 kg it needs 70 mm more width than the three-pole version, so do not assume that a three-pole cut-out can be reused. Its DC lines are also given for a four-pole series arrangement at 250 V.

ComPacT INS references compared with the 31331

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 31331 with its neighbours:

Frame, handle and mounting of the 31331

The 31331 measures 300 mm high, 410 mm wide and 146.5 mm deep, at a connection pitch of 70 mm, and weighs 18 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 3000 cycles, and the electrical durability is 500 cycles in AC-21A, AC-22A and AC-23A, and 500 cycles in the DC categories. 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 31331

Mount the 31331 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 500 cycles in AC-21A, AC-22A and AC-23A, and 500 cycles in the DC categories 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 31331

Before ordering the 31331, collect the following.

• Rated current: 800 A, with the operational current in the category that matches the load (AC-21A, AC-22A, AC-23A or a DC category).
• Poles: 4, and whether the neutral must be switched.
• Voltage: up to 690 V AC, and 250 V DC with four poles in series for DC.
• Prospective short-circuit current compared with the 75 kA making capacity alone and the upstream breaker.
• Space: 300 x 410 x 146.5 mm, 18 kg, 70 mm pitch.
• Cabinet temperature compared with -25 to 70 °C operation.

Where the 31331 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 31331 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.