Kraus & Naimer 25-250A AC Isolator | 3 & 4 Pole | IP66/67

Description

Kraus & Naimer AC switch-disconnectors give you safe, lockable isolation for AC supplies, from 25A up to 250A. The range is built around two configurations: 3-pole switches for single-phase circuits and 4-pole switches for three-phase circuits (three phases plus a switched neutral). Each switch sits in an insulated IP66/67 enclosure and is manufactured to EN 60947-3 / VDE 0660 part 107.

Every unit has a padlockable OFF position and a lid interlocked with the switch, so the enclosure cannot be opened while the switch is ON. An earth terminal is included as standard, and the grey enclosure takes a red handle with yellow escutcheon plate for main and emergency-off duty (a black/grey handle is available as an option).

25-250A

AC-21A rated current

3 Pole

Single-phase versions

4 Pole

Three-phase + switched neutral

IP66/67

Insulated enclosure

690V

Insulation voltage Ui (25-100A)

EN 60947-3

Switchgear standard

Pole count: match the part number to your supply

Single-phase variants are 3-pole (T203 codes) and three-phase variants are 4-pole (T204 codes: 3 phases plus switched neutral). Check the code in the variant table below before ordering, as the two types use different order codes at every current rating.

Isolation only: upstream protection still required

A switch-disconnector isolates a circuit; it is not a substitute for overcurrent or short-circuit protection. Always protect the circuit with a correctly rated fuse or breaker upstream (maximum gL/gG fuse ratings are listed below). Installation must comply with BS 7671 and be carried out by a competent person.

Key Features

3-Pole and 4-Pole Versions

3-pole switches (T203) suit single-phase circuits and 4-pole switches (T204) suit three-phase circuits with a switched neutral. On the 4-pole version the neutral pole is early make / late break.

Padlockable OFF Position

The handle can be padlocked in the OFF position, so the supply stays isolated while maintenance is carried out.

Lid Interlock

The lid is mechanically interlocked with the switch to prevent opening in the ON position, an essential safety feature when working on connected equipment.

IP66/67 Insulated Enclosure

A grey insulated enclosure (RAL 7035) rated IP66/67 with knockout cable entries suits exposed outdoor positions as well as indoor panels (160A and 250A use gland plates).

Earth Terminal Included

An earth terminal is included as standard on every variant, ready for a proper protective earth connection.

Finger-Proof Terminals

Terminals are finger-proof to VDE 0660-514 and BGV A3 (IP20), with terminal capacity from 6 mm² up to 185 mm² depending on the rating.

AC Switch-Disconnector Variants

Ratings are AC-21A operational current. Enclosure sizes are height × width × depth in mm. Cable capacity shows rigid (single core or stranded) / flexible conductors in mm².

Single-Phase Switch-Disconnectors (3-Pole)

Part Number

Rating

Poles

AC-23A 400V

Max Fuse gG

Cable (rigid / flex)

Enclosure (mm)

KG20-T203-GBA294

25A

3

7.5 kW

35A

6 / 4

160 × 85 × 82

KG32-T203-GBA294

32A

3

11 kW

35A

6 / 4

160 × 85 × 82

KG41-T203-GBA270

40A

3

15 kW

50A

16 / 10

190 × 100 × 93

KG64-T203-GBA270

63A

3

22 kW

63A

16 / 10

190 × 100 × 93

KG100-T203-GBA270

100A

3

37 kW

100A

50 / 35

250 × 145 × 107

Three-Phase Switch-Disconnectors (4-Pole: 3 Phases + Switched Neutral)

Part Number

Rating

Poles

AC-23A 400V

Max Fuse gG

Cable (rigid / flex)

Enclosure (mm)

KG20-T204-GBA486

25A

4

7.5 kW

35A

6 / 4

160 × 85 × 82

KG32-T204-GBA486

32A

4

11 kW

35A

6 / 4

160 × 85 × 82

KG41-T204-GBA290

40A

4

15 kW

50A

16 / 10

190 × 100 × 93

KG64-T204-GBA290

63A

4

22 kW

63A

16 / 10

190 × 100 × 93

KG80-T204-GBA290

80A

4

30 kW

80A

50 / 35

250 × 145 × 107

KG100-T204-GBA290

100A

4

37 kW

100A

50 / 35

250 × 145 × 107

KG160-T204-GBA290-ST

160A

4

55 kW

160A

95 / 70

380 × 280 × 180

KG250-T204-GBA290-ST

250A

4

90 kW

250A

185 / 120

560 × 380 × 180

Rating note

The KG64 series is rated 63A. Where a cable size or fuse is quoted, the figures are the manufacturer's switch ratings; always size the circuit to the connected load and your own design calculations.

Technical Specification

General

Switch Type

AC switch-disconnector, main / emergency-off

Applicable Standard

EN 60947-3 / VDE 0660 part 107

Rated Current Range

25A to 250A (AC-21A)

Poles

3-pole (single-phase, T203) or 4-pole (three-phase + switched neutral, T204)

Rated Insulation Voltage Ui

690V on 25A to 100A. 160A and 250A: 1000V (above 690V valid for no-load switching only)

Ambient Temperature

35°C average over 24 hours, peaks up to 40°C

Construction

Enclosure

Insulated polycarbonate, grey (RAL 7035)

Ingress Protection

IP66/67

Handle and Escutcheon

Red handle with contrasting yellow escutcheon plate. Black/grey handle available as an option for main switch use

Cable Entries

Knockout entries (gland plates on 160A and 250A)

Terminals

Finger-proof to VDE 0660-514 and BGV A3, IP20

Copper Conductors

Use copper wire only

Safety Features

Lockable OFF Position

Padlockable in the OFF position

Lid Interlock

Switch interlocked with the lid to prevent opening in the ON position

Earth Terminal

Included as standard

Neutral Pole (4-pole)

Switched neutral is early make / late break

Frequently Asked Questions

How many poles do the single-phase and three-phase versions have?

Single-phase variants are 3-pole (T203 codes such as KG20-T203-GBA294) and three-phase variants are 4-pole (T204 codes such as KG20-T204-GBA486), switching three phases plus the neutral. On the 4-pole version the switched neutral is early make / late break.

Which part number should I choose?

Pick the rating you need, then the pole count for your supply: T203 for single-phase or T204 for three-phase. The single-phase range runs 25A, 32A, 40A, 63A and 100A. The three-phase range runs 25A, 32A, 40A, 63A, 80A, 100A, 160A and 250A.

Can the switch be padlocked and is the lid interlocked?

Yes. The OFF position can be padlocked, and the lid is interlocked with the switch so the enclosure cannot be opened while the switch is ON.

What ingress protection do these isolators have?

They are rated IP66/67 in an insulated grey enclosure with knockout cable entries (gland plates on the 160A and 250A units), so they suit outdoor and indoor locations.

Does the switch protect against overcurrent or short circuits?

No. It is an isolating switch, not a protective device. Fit a correctly rated fuse or breaker upstream. The manufacturer's maximum gG fuse ratings are 35A (25A and 32A), 50A (40A), 63A (63A), 80A (80A), 100A (100A), 160A (160A) and 250A (250A).

What standards and temperature limits apply?

The switches are manufactured to EN 60947-3 (VDE 0660 part 107) and are rated for an ambient temperature of 35°C averaged over 24 hours, with peaks up to 40°C.

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