MILITARY—ENVIRONMENTALLY SEALED SWITCHES
Series—8573, 8574, 8575
MIL-S-3950 IWTS Lever Locks
FEATURES
SPECIFICATIONS
• Environmentally sealed
• Environmentally sealed per MIL-S-3950
• 1, 2, and 4 pole circuitry
• MS approved and QPL’d per MIL-S-3950
• 2 & 3 position with maintained and
• Thermoset molding materials meet flame
momentary action
retardant requirements
• Integrated wire termination system
• Bushing: 15/32" - 32 thread
(IWTS) for ease of wiring
• Temperature Range: -85°F to +160°F
• Terminal numbers molded into silicone
(-65°C to +71°C)
base seal
• Accepts MIL-C-39029/1-101 pin
• Life: 20,000 operations at rated load
40,000 operations mechanical life
CURRENT RATINGS
No. of Catalog
Type of
Poles Number Operation
28VDC
Lamp Resistive Inductive
Load
Load
Load
5
20
15
4
15
10
7
20
15
5
18
10
5
20
12
4
18
10
115VAC
60 or 400Hz
Lamp Resistive Inductive
Load
Load
Load
3
15
10
2
15
7
4
15
15
2
11
8
4
15
15
2
11
8
1
2
4
8573
8574
8575
Maintained
Momentary
Maintained
Momentary
Maintained
Momentary
Minimum Rating: “Intermediate Current” per MIL-S-3950
LEVER LOCK SELECTION TABLE – T er minals Accept W
Ter minals Accept W
ir e Contact Within Dimensional Limits of M39029/1-102 for -16 wire size
ir e Contact Within Dimensional Limits of M39029/1-101 for -20 wire size
8573
CIRCUIT WITH LEVER IN...
Up
Position
Center
Position
Down
Position (Keyway)
Lever
x
Lock
Bushing
Style
8574
TWO POLE
Flush Screw Terminals
MS Part
Catalog
Number
Number
8574K1-16
K27-16
K5-16
K2-16
K28-16
8574K3-16
K29-16
K30-16
K31-16
K32-16
8574K33-16
K4-16
K34-16
K10-16
K35-16
8574K9-16
K6-16
K36-16
K7-16
K16-16
8574K37-16
K38-16
K11-16
K22-16
K20-16
8574K12-16
K39-16
K14-16
K15-16
K21-16
8574K19-16
K18-16
K40-16
K41-16
K13-16
8575
FOUR POLE
Flush Screw Terminals
MS Part
Catalog
Number
Number
MS27783-21A
-21B
-21D
-21E
-21F
MS27783-21G
-21H
-21J
-21K
-21L
MS27783-21M
-21N
-21P
-22D
-22F
MS27783-22G
-23D
-23F
-23G
-24E
MS27783-24F
-24K
-24M
-25F
-26F
MS27783-27E
-27L
-27N
-28E
-29F
MS27783-30F
-31E
-31F
-31K
-31L
8575K1-16
K27-16
K5-16
K2-16
K28-16
8575K3-16
K29-16
K30-16
K31-16
K32-16
8575K33-16
K4-16
K34-16
K10-16
K35-16
8575K9-16
K6-16
K36-16
K7-16
K16-16
8575K37-16
K38-16
K11-16
K22-16
K20-16
8575K12-16
K39-16
K14-16
K15-16
K21-16
8575K19-16
K18-16
K40-16
K41-16
K13-16
ONE POLE
Flush Screw Terminals
MS Part
Catalog
Number
Number
*
*
*
ON§
OFF§
ON
A
ON
OFF§
ON
B
ON§
OFF
ON
D
ON
OFF§
ON
E
ON§
OFF
ON
F
ON
OFF
ON
G
ON§
OFF§
ON
H
ON
OFF
ON
J
ON§
OFF§
ON
K
ON
OFF§
ON
L
ON§
OFF
ON
M
ON
OFF
ON
N
ON
OFF§
ON
P
ON§
NONE
OFF
D
ON§
NONE
OFF
F
ON
NONE
OFF
G
ON§
NONE
ON
D
ON§
NONE
ON
F
ON
NONE
ON
G
ON
OFF§
NONE
E
ON§
OFF
NONE
F
ON§
OFF§
NONE
K
ON§
OFF
NONE
M
ON§
OFF
NONE
F
ON§
NONE
ON
F
ON
OFF§
ON
E
ON
OFF§
ON
L
ON
OFF
ON
N
NONE
OFF§
ON
E
ON§
NONE
OFF
F
OFF§
NONE
ON
F
ON
OFF§
ON
E
ON§
OFF
ON
F
ON§
OFF§
ON
K
ON
OFF§
ON
L
Momentary contact.
§
Indicates direction against which lever is locked.
*
*
*
*
*
*
*
*
*
*
*
*
*
MS27781-21A
8573K1-16
MS27782-21A
-21B
K27-16
-21B
-21D
K5-16
-21D
-21E
K2-16
-21E
-21F
K28-16
-21F
MS27781-21G
8573K3-16
MS27782-21G
-21H
K29-16
-21H
-21J
K30-16
-21J
-21K
K31-16
-21K
-21L
K32-16
-21L
MS27781-21M
8573K33-16
MS27782-21M
-21N
K4-16
-21N
-21P
K34-16
-21P
-22D
K10-16
-22D
-22F
K35-16
-22F
MS27781-22G
8573K9-16
MS27782-22G
-23D
K6-16
-23D
-23F
K36-16
-23F
-23G
K7-16
-23G
-24E
K16-16
-24E
MS27781-24F
8573K37-16
MS27782-24F
-24K
K38-16
-24K
-24M
K11-16
-24M
-25F
K22-16
-25F
-26F
K20-16
-26F
MS27781-27E
8573K12-16
MS27782-27E
-27L
K39-16
-27L
-27N
K14-16
-27N
-28E
K15-16
-28E
-29F
K21-16
-29F
MS27781-30F
8573K19-16
MS27782-30F
-31E
K18-16
-31E
-31F
K40-16
-31F
-31K
K41-16
-31K
31L
K13-16
-31L
See page 73 for circuit diagrams.
x
Reference bushing styles on Page 42.
MILITARY—ENVIRONMENTALLY SEALED SWITCHES
Series—8573, 8574, 8575
LEVER LOCK SELECTION TABLE, CON’T.
MIL-S-3950 IWTS Lever Locks
8573
CIRCUIT WITH LEVER IN...
Up
Position
Center
Position
Down
Position (Keyway)
Lever
x
Lock
Bushing
Style
8574
TWO POLE
Flush Screw Terminals
MS Part
Catalog
Number
Number
MS27782-31M
-31N
-32E
-33E
-33F
MS27782-33K
-33M
-1A
-1B
-1D
MS27782-1E
-1F
-1G
-1H
-1J
MS27782-1K
-1L
-1M
-1N
-1P
MS27782-2E
-2F
-2K
-2L
-2M
MS27782-2N
-3E
-3L
-3N
8574K17-16
K8-16
K23-16
K24-16
K25-16
8574K26-16
K42-16
K65-16
K66-16
K67-16
8574K68-16
K69-16
K70-16
K71-16
K72-16
8574K73-16
K74-16
K75-16
K76-16
K77-16
574K78-16
K79-16
K80-16
K81-16
K82-16
8574K83-16
K84-16
K85-16
K86-16
8575
FOUR POLE
Flush Screw Terminals
MS Part
Catalog
Number
Number
MS27783-31M
-31N
-32E
-33E
-33F
MS27783-33K
-33M
-1A
-1B
-1D
MS27783-1E
-1F
-1G
-1H
-1J
MS27783-1K
-1L
-1M
-1N
-1P
MS27783-2E
-2F
-2K
-2L
-2M
MS27783-2N
-3E
-3L
-3N
8575K17-16
K8-16
K23-16
K24-16
K25-16
8575K26-16
K42-16
K43-16
K44-16
K45-16
8575K46-16
K47-16
K48-16
K49-16
K50-16
8575K51-16
K52-16
K53-16
K54-16
K55-16
8575K56-16
K57-16
K58-16
K59-16
K60-16
8575K61-16
K62-16
K63-16
K64-16
ONE POLE
Flush Screw Terminals
MS Part
Catalog
Number
Number
MS27781-31M
-31N
-32E
-33E
-33F
MS27781-33K
-33M
–
–
–
–
8573K17-16
K8-16
K23-16
K24-16
K25-16
8573K26-16
K42-16
–
–
–
–
*
`
*
*
*
ON§
OFF
ON
M
ON
OFF
ON
N
ON
ON§
NONE
E
ON
ON§
NONE
E
ON§
ON
NONE
F
ON§
ON§
NONE
K
ON§
ON
NONE
M
ON§
ON§
ON
A
ON
ON§
ON
B
ON§
ON
ON
D
ON
ON§
ON
E
ON§
ON
ON
F
ON
ON
ON
G
ON§
ON§
ON
H
ON
ON
ON
J
ON§
ON§
ON
K
ON
ON§
ON
L
ON§
ON
ON
M
ON
ON
ON
N
ON
ON§
ON
P
ON
ON§
ON
E
ON§
ON
ON
F
ON§
ON§
ON
K
ON
ON§
ON
L
ON§
ON
ON
M
ON
ON
ON
N
ON
ON§
ON
E
ON
ON§
ON
L
ON
ON
ON
N
Momentary contact.
§
Indicates direction against which lever is locked.
See page 73 for circuit diagrams.
x
Reference bushing styles on Page 42.
*
*
–
–
*
*
*
*
*
*
*
*
*
*
–
–
–
–
MILITARY—ENVIRONMENTALLY SEALED SWITCHES
Series—8573, 8574, 8575
MIL-S-3950 IWTS Lever Locks
CIRCUIT WITH LEVER IN...
Up
Position
Center
Position
Down
Position (Keyway)
Lever
x
Lock
Bushing
Style
A
B
D
E
F
G
H
J
K
L
M
N
P
D
F
G
D
F
G
E
F
K
M
F
F
E
L
N
E
F
F
E
F
K
L
ONE POLE
Flush Screw Terminals
MS Part
Catalog
Number
Number
MS27787-21A
-21B
-21D
-21E
-21F
MS27787-21G
-21H
-21J
-21K
-21L
MS27787-21M
-21N
-21P
-22D
-22F
MS27787-22G
-23D
-23F
-23G
-24E
MS27787-24F
-24K
-24M
-25F
-26F
MS27787-27E
-27L
-27N
-28E
-29F
MS27787-30F
-31E
-31F
-31K
31L
MS27787-31M
-31N
-32E
-33E
-33F
MS27787-33K
-33M
–
–
–
–
8573K1-20
K27-20
K5-20
K2-20
K28-20
8573K3-20
K29-20
K30-20
K31-20
K32-20
8573K33-20
K4-20
K34-20
K10-20
K35-20
8573K9-20
K6-20
K36-20
K7-20
K16-20
8573K37-20
K38-20
K11-20
K22-20
K20-20
8573K12-20
K39-20
K14-20
K15-20
K21-20
8573K19-20
K18-20
K40-20
K41-20
K13-20
8573K17-20
K8-20
K23-20
K24-20
K25-20
8573K26-20
K42-20
–
–
–
–
TWO POLE
Flush Screw Terminals
MS Part
Catalog
Number
Number
MS27788-21A
-21B
-21D
-21E
-21F
MS27788-21G
-21H
-21J
-21K
-21L
MS27788-21M
-21N
-21P
-22D
-22F
MS27788-22G
-23D
-23F
-23G
-24E
MS27788-24F
-24K
-24M
-25F
-26F
MS27788-27E
-27L
-27N
-28E
-29F
MS27788-30F
-31E
-31F
-31K
-31L
MS27788-31M
-31N
-32E
-33E
-33F
MS27788-33K
-33M
-1A
-1B
-1D
MS27788-1E
-1F
-1G
-1H
-1J
MS27788-1K
-1L
-1M
-1N
-1P
MS27788-2E
-2F
-2K
-2L
-2M
MS27788-2N
-3E
-3L
-3N
8574K1-20
K27-20
K5-20
K2-20
K28-20
8574K3-20
K29-20
K30-20
K31-20
K32-20
8574K33-20
K4-20
K34-20
K10-20
K35-20
8574K9-20
K6-20
K36-20
K7-20
K16-20
8574K37-20
K38-20
K11-20
K22-20
K20-20
8574K12-20
K39-20
K14-20
K15-20
K21-20
8574K19-20
K18-20
K40-20
K41-20
K13-20
8574K17-20
K8-20
K23-20
K24-20
K25-20
8574K26-20
K42-20
K65-20
K66-20
K67-20
8574K68-20
K69-20
K70-20
K71-20
K72-20
8574K73-20
K74-20
K75-20
K76-20
K77-20
8574K78-20
K79-20
K80-20
K81-20
K82-20
8574K83-20
K84-20
K85-20
K86-20
FOUR POLE
Flush Screw Terminals
MS Part
Catalog
Number
Number
MS27789-21A
-21B
-21D
-21E
-21F
MS27789-21G
-21H
-21J
-21K
-21L
MS27789-21M
-21N
-21P
-22D
-22F
MS27789-22G
-23D
-23F
-23G
-24E
MS27789-24F
-24K
-24M
-25F
-26F
MS27789-27E
-27L
-27N
-28E
-29F
MS27789-30F
-31E
-31F
-31K
-31L
MS27789-31M
-31N
-32E
-33E
-33F
MS27789-33K
-33M
-1A
-1B
-1D
MS27789-1E
-1F
-1G
-1H
-1J
MS27789-1K
-1L
-1M
-1N
-1P
MS27789-2E
-2F
-2K
-2L
-2M
MS27789-2N
-3E
-3L
-3N
8575K1-20
K27-20
K5-20
K2-20
K28-20
8575K3-20
K29-20
K30-20
K31-20
K32-20
8575K33-20
K4-20
K34-20
K10-20
K35-20
8575K9-20
K6-20
K36-20
K7-20
K16-20
8575K37-20
K38-20
K11-20
K22-20
K20-20
8575K12-20
K39-20
K14-20
K15-20
K21-20
8575K19-20
K18-20
K40-20
K41-20
K13-20
8575K17-20
K8-20
K23-20
K24-20
K25-20
8575K26-20
K42-20
K43-20
K44-20
K45-20
8575K46-20
K47-20
K48-20
K49-20
K50-20
8575K51-20
K52-20
K53-20
K54-20
K55-20
8575K56-20
K57-20
K58-20
K59-20
K60-20
8575K61-20
K62-20
K63-20
K64-20
*
*
*
ON§
ON
ON§
ON
ON§
ON
ON§
ON
ON§
ON
ON§
ON
ON
ON§
ON§
ON
ON§
ON§
ON
ON
ON§
ON§
ON§
ON§
ON§
ON
ON
ON
NONE
ON§
OFF§
ON
ON§
ON§
ON
OFF§
OFF§
OFF
OFF§
OFF
OFF
OFF§
OFF
OFF§
OFF§
OFF
OFF
OFF§
NONE
NONE
NONE
NONE
NONE
NONE
OFF§
OFF
OFF§
OFF
OFF
NONE
OFF§
OFF§
OFF
OFF§
NONE
NONE
OFF
OFF
OFF§
OFF§
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
ON
OFF
OFF
OFF
ON
ON
ON
NONE
NONE
NONE
NONE
NONE
ON
ON
ON
ON
ON
OFF
ON
ON
ON
ON
ON
*
*
*
*
ON§
OFF
M
ON
OFF
N
ON
ON§
E
ON
ON§
NONE
E
ON§
ON
NONE
F
ON§
ON§
NONE
K
ON§
ON
NONE
M
ON§
ON§
ON
A
ON
ON§
ON
B
ON§
ON
ON
D
ON
ON§
ON
E
ON§
ON
ON
F
ON
ON
ON
G
ON§
ON§
ON
H
ON
ON
ON
J
ON§
ON§
ON
K
ON
ON§
ON
L
ON§
ON
ON
M
ON
ON
ON
N
ON
ON§
ON
P
ON
ON§
ON
E
ON§
ON
ON
F
ON§
ON§
ON
K
ON
ON§
ON
L
ON§
ON
ON
M
ON
ON
ON
N
ON
ON§
ON
E
ON
ON§
ON
L
ON
ON
ON
N
Momentary contact.
§
Indicates direction against which lever is locked.
See page 73 for circuit diagrams.
x
Reference bushing styles on Page 42.
*
*
*
*
*
*
*
*
*
*
*
ON
ON
*
NO
*
NE
–
–
*
*
*
*
*
*
*
*
*
*
–
–
–
–
MILITARY—ENVIRONMENTALLY SEALED SWITCHES
Series—8573, 8574, 8575
MOUNTING DIMENSIONS—ONE POLE / 8573
MIL-S-3950 IWTS Lever Locks
Terminal Identification
MOUNTING DIMENSIONS—TWO POLE / 8574
STANDARD
0.00 = inches
[0,0] = mm
Mounting dimensions for reference only.
Non-functional terminals not supplied.
Terminal Identification
MILITARY—ENVIRONMENTALLY SEALED SWITCHES
Series—8573, 8574, 8575
MOUNTING DIMENSIONS—FOUR POLE / 8575
MIL-S-3950 IWTS Lever Locks
Terminal Identification
OPTIONS/ACCESSORIES
• Special mounting hardware
• Mounting hardware furnished assembled
• Special circuits
• Panel seal, part number 32-341 (See Accessories
and Custom Components section)
• Special shaped caps available
• Custom wiring harnesses
LEVER LOCK – BUSHING STYLES
KEYWAY SIDE
PANEL CUTOUT DIMENSIONS
STANDARD
0.00 = inches
[0,0] = mm
Mounting dimensions for reference only.
stm32/stm8
