TECHNICAL DATASHEET

Load Break Isolating Switches

MS79 Series
n 3 and 4 pole versions
n 125A to 1800A versions
n 6 and 8 pole versions up to 1250A (contact IMO)
n Handles with door interlock
n 3 padlock positions
n Chassis mount
n Choice of handles
n Choice of shaft lengths
n Full range of accessories
n Severe utilisation categories (AC-22 and AC-23)

Options and ordering codes

Shaft for Terminal Cage terminals

IMO P/N(1) Rating (A) No. of poles(3) Direct Handle External Handle Auxiliary contact
external handle shroud(5) with cover

MS793125 3
125A 3 Pole
MS794125 4 79S1002
Contact IMO Contact IMO
MS793160 3 4 Pole
160A 79S1010
MS794160 4

MS793200 3
200A 200mm 3 Pole
MS794200 4 79E1010 79S1004
S2 Type Contact IMO
250mm 4 Pole
MS793250 3 Black IP65
79E1011 79S1012
250A 79H1008(2)
MS794250 4 320mm
Red & Yellow IP65
79E1012(2)
B2 Type 79H1009
MS793315 3 500mm
315A Black 79E1013
MS794315 4 79H0007
1st Contact CO 3 Pole
MS793400 3 79A0002 79S1006
400A Contact IMO
MS794400 4 2nd Contact CO 4 Pole
79A0003 79S1014
MS793630 3
630A
MS794630 4

MS793800 3
800A 3 Pole
MS794800 4 79S1007
MS7931000 3 4 Pole
1000A C2 Type 79S1022
320mm
MS7941000 4 Black S4 Type
79E1015(2)
79H0023 Black IP65
MS7931250 3 400mm
Red & Yellow 79H1016
1250A 79E1016 3 Pole
79H0021
MS7941250 4 79S1023
MS7931800 3 4 Pole
1800A Contact IMO
MS7941800 4

(1) Device available enclosed

(2) Standard
(3) Top or bottom

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Specification according to IEC 60947-3

125 to 800 A

Thermal current Ith at 40oC 125 A 160 A 200 A 250 A 315 A 400 A 500 A 630 A 800 A

Rated insulation voltage Ui (V) 800 800 800 800 1000 1000 1000 1000 1000

Rated impulse withstand voltage Uimp (kV) 8 8 8 8 12 12 12 12 12

Rated operational currents Ie (A)

Rated voltage Utilisation category A/B(1) A/B(1) A/B(1) A/B(1) A/B(1) A/B(1) A/B(1) A/B(1) A/B(1)

415 VAC AC-20 A/ AC-20 B 125 160 200 250 315 400 500 630 800

415 VAC AC-21 A/ AC-21 B 125 160 200 250 315 400 500 630 800

415 VAC AC-22 A/ AC-22 B 125 160 200 250 315 400 500 630 800

415 VAC AC-23 A/ AC-23 B 125 160 200 250 315 400 500 500 800

220 VDC DC-20 A/ DC-20 B 125 160 200 250 315 400 500 630 800

220 VDC DC-21 A/ DC-21 B 125 160 160/200 250 315 400 500 630 800

220 VDC DC-22 A/ DC-22 B 125 160 160/200 250 315 400 400/500 500 800

220 VDC DC-23 A/ DC-23 B 125 160 200 250 315 400 400 500 800

440 VDC DC-20 A/ DC-20 B 125 160 200 250 315 400 500 630 800

440 VDC DC-21 A/ DC-21 B 125 (3)

160 (3)
160 /200
(3) (3)
200 (3)
315 (3)
400 (3)
400 (3)
500 (3)
800(4)

440 VDC DC-22 A/ DC-22 B 125(3) 125(3) 160(3) 200(3) 315(3) 400(3) 400(3) 500(3) 800(4)

440 VDC DC-23 A/ DC-23 B 125 (4)

125 (4)
160 (4)
200 (4)
315 (4)
400 (4)
400 (4)
500 800(4)

500 VDC DC-20 A/ DC-20 B 125 160 200 250 315 400 500 630 800

500 VDC DC-21 A/ DC-21 B 125 (3)

125 (3)
160 /200
(3) (3)
200 (3)
315 (3)
400 (3)
400 (3)
500 (3)
800(4)

500 VDC DC-22 A/ DC-22 B 125(4) 125(4) 160(4) 200(4) 315(4) 315(4)/400(4) 315(4)/400(4) 500(4) 800(4)

500 VDC DC-23 A/ DC-23 B 125 (4)

125 (4)
160 (4)
200 (4)
315 (4)
315 /400
(4) (4)
315 /400
(4) (4)
500 (4)
800(4)

Operational power in AC-23 A (kW)(1)(5)

At 415 VAC without pre-break in AC(1) 63 80 100 132 160 220 280 280 450

Reactive power (kvar)

At 400 VAC (kvar)(5) 55 75 90 115 145 185 230 290 365

Fuse protected short-circuit withstand (kA rms prospective)(6)

Prospective short-circuit current (kA rms) 100 100 80 50 100 100 100 70 50

Associated fuse rating (A) 125 160 200 250 315 400 500 630 800

Circuit breaker protected short-circuit withstand with any circuit breaker that
ensures tripping in less than 0.3s at 690 VAC

Rated short-time withstand current 0.3s. ICW (kA rms) 15 15 17 17 25 25 25 25 50

Short-circuit capacity (without protection)

Rated short-time withstand current 1s. ICW (kA rms) 7 7 9 9 13 13 13 13 35

Rated short-circuit making capacity without fuses Icm (kA peak) 11.9 11.9 15.3 15.3 26 26 26 26 73.5

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Connection

Maximum Cu cable cross-section (mm2) 35 50 70 95 150 185 240 2 x 150 2 x 185

Minimum busbar cross-section (mm2) 2 x 30 x 5 2 x 40 x 5

Maximum Cu cable cross-section (mm2) 50 95 95 150 240 240 240 2 x 300 2 x 300

Maximum Cu busbar width (mm) 25 25 32 32 40 40 40 50 63

Tightening torque min//max (Nm) 9/- 9/- 20/- 20/- 20/- 20/- 20/- 20/- 40/45

Mechanical characteristics

Durability (number of operating cycles) 10000 10000 10000 10000 10000 10000 10000 10000 10000

Operating effort (Nm) 6.5 6.5 10 10 10 14.5 14.5 14.5 37

Weight of a 3 pole device (kg) 1 1 2 2 3.5 3.5 3.5 3.5 8

Weight of a 4 pole device (kg) 1.5 1.5 2 2 4 4 4.5 4.5 10

(1) Category with index A = frequent operation / Category with index B = infrequent operation
(2) With terminal shroud or phase barrier
(3) 3-pole device with 2 poles in series for the ‘+’ and 1 pole for the ‘-’
(4) 4-pole device with 2 poles in series per polarity
(5) The power value is given for information only, the values vary from a manufacturer to another
(6) For a rated operational voltage Ue = 400 VAC

1000 to 1800 A

Thermal current Ith at 40oC 1000 A 1250 A 1600 A 1800 A

Rated insulation voltage Ui (V) 1000 1000 1000 1000

Rated impulse withstand voltage Uimp (kV) 12 12 12 12

Rated operational currents Ie (A)

Rated voltage Utilisation category A/B(1) A/B(1) A/B(1) A/B(1)

415 VAC AC-20 A/ AC-20 B 1000 1250 1600 1800

415 VAC AC-21 A/ AC-21 B 1000 1250 1600 1800

415 VAC AC-22 A/ AC-22 B 1000 1250 1600 1800

415 VAC AC-23 A/ AC-23 B 1000 1250 1250 1250

220 VDC DC-20 A/ DC-20 B 1000 1250 1600 1800

220 VDC DC-21 A/ DC-21 B 1000 1250 1250/1600 1250/1600

220 VDC DC-22 A/ DC-22 B 1000 1250 1250 1250

220 VDC DC-23 A/ DC-23 B 1000 1250 1250 1250

440 VDC DC-20 A/ DC-20 B 1000 1250 1600 1800

440 VDC DC-21 A/ DC-21 B 1000(4) 1250(4) 1250(4)/1600(4) 1250(4)/1600(4)

440 VDC DC-22 A/ DC-22 B 1000(4) 1250(4) 1250(4) 1250(4)

440 VDC DC-23 A/ DC-23 B 1000(4) 1250(4) 1250(4) 1250(4)

500 VDC DC-20 A/ DC-20 B 1000 1250 1600 1800

500 VDC DC-21 A/ DC-21 B 1000(4) 1250(4) 1250(4)/1600(4) 1250(4)/1600(4)

500 VDC DC-22 A/ DC-22 B 1000(4) 1250(4) 1250(4) 1250(4)

500 VDC DC-23 A/ DC-23 B 1000(4) 1250(4) 1250(4) 1250(4)

Operational power in AC-23 A (kW)(1)(5)

At 415 VAC without pre-break in AC(1) 560 710 710 710

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Reactive power (kvar)

At 400 VAC (kvar)(5) 460

Fuse protected short-circuit withstand (kA rms prospective)(6)

Prospective short-circuit current (kA rms) 100 100 100 100

Associated fuse rating (A) 1000 1250 2 x 800 2 x 800

Circuit breaker protected short-circuit withstand with any circuit breaker that
ensures tripping in less than 0.3s at 690 VAC

Rated short-time withstand current 0.3s. ICW (kA rms) 65 100 100 100

Short-circuit capacity (without protection)

Rated short-time withstand current 1s. ICW (kA rms) 35 50 50 50

Rated short-circuit making capacity without fuses Icm (kA peak) 73.5 75 75 75

Connection

Maximum Cu cable cross-section (mm2) 2 x 240

Minimum busbar cross-section (mm2) 2 x 50 x 5 2 x 60 x 5 2 x 80 x 5 3 x 100 x 5

Maximum Cu cable cross-section (mm ) 2

4 x 185 4 x 185 6 x 185 6 x 185

Maximum Cu busbar width (mm) 63 100 100 100

Tightening torque min//max (Nm) 40/45 40/45 40/45 40/45

Mechanical characteristics

Durability (number of operating cycles) 3000 4000 4000 4000

Operating effort (Nm) 37 56 56 56

Weight of a 3 pole device (kg) 8 12 12 12

Weight of a 4 pole device (kg) 10 15 15 15

(1) Category with index A = frequent operation / Category with index B = infrequent operation
(2) With terminal shroud or phase barrier
(3) 3-pole device with 2 poles in series for the ‘+’ and 1 pole for the’-’
(4) 4-pole device with 2 poles in series per polarity
(5) The power value is given for information only, the values vary from a manufacturer to another
(6) For a rated operational voltage Ue = 400 VAC

MS79 125 to 630A

Direct front operation External front operation

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Terminal
Rating (A) Overall dimension Switch body
Shrouds

C D AC AD F F G H J1 J1 J2 K BC

min. 3p 4p 3p 4p

125 ... 160 115 125 235 50 140 170 93 65 45 75 75 31.5 80

200 ... 250 280 60 180 230 108 75 55 105 105 34 115

315 ... 400 160 165 401 89 230 190 170 110 75 135 135 55 115

Rating (A) Switch mounting Connection

M M N R T U U1 V W X1 X1 X2 Y Z AA BA CA

3p 4p 3p 4p

125 ... 160 120 150 65 5.5 36 20 20.5 25 8 28 22 20 3.5 20.5 135 115 10

200 ... 250 160 210 80 5.5 50 20 25.5 21.5 11 33 22 27 3.5 22.5 160 130 15

315 ... 400 210 270 140 7 65 32 45.5 29 11 37.5 37.5 36 5 36 235 205 15

MS79 800 to 1800A

Direct front operation External front operation

Rating (A) F 3p F 4p M 3p M 4p T U V Y X1 X2 Z AA

800 ... 1000 280 360 255 335 80 50 60.5 7 47.5 47.5 46.5 321

1250 ... 1800 372 492 492 467 120 90 44 8 53.5 53.5 47.5 288

Dimensions - External handles

MS79 125 to 630A

Front operation
Handle type Door drilling template
Direction of operation

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Front operation
Handle type Door drilling template
Direction of operation

Right side operation

MS79 800 to 1800A

Front operation
Handle type Door drilling template
Direction of operation

Handle types

External Direct

Type S2 S2 S4 B2 C2

P/N 79H1008 79H1009 79H1016 79H0007 79H0023

Parts needed for external operation

MS79

Shaft

Handle

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Options and ordering codes - Auxiliary contact block

USE Characteristics:
Pre-break and signalling of positions 0 and I: NO/NC A/C: IP2 with front operation
- 1 to 2 NO/NC auxiliary contacts. Connection to the control circuit
- 1 to 4 NO/NC auxiliary contacts. 6.35mm fast-on terminal
- 1 to 2 low level NO/NC auxiliary contacts. Electrical Characteristics
30000 operations

IMO P/N Rating (A) Position A/C

79A0002 125 ... 1800 1st

79A0003 125 ... 1800 2nd

Options and ordering codes - Shaft extension 1st 2nd

IMO P/N Length Use with

79E1010 200mm 125 to 630A

79E1011 250mm 126 to 630A

79E1012 320mm 125 to 630A

79E1013 500mm 125 to 630A

79E1015 320mm 800 to 1800A

79E1016 400mm 800 to 1800A

Shaft Guide for external operation

USE
For utilisation with S-type handles, to guide the shaft extension into the external handle.
This accessory enables the handle to engage the shaft with misalignment of up to 15mm
Required for shaft lengths over 320mm

Shaft Guide

IMO P/N

79AD001

Ref: MS79 V1 0917 Errors and omissions excepted. Subject to change without notice. www.imopc.com