Time Current Curves TD012036EN
Effective December 2015
Series C MDL-Frame
400-800A, 240-600V
Contents
DescriptionPage
Catalog Number Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Digitrip RMS 310+ Electronic Trip Units
MDL, HMDL, CMDL, CHMDL, MDLB, HMLDB; 800A; 3- and 4-pole; LS and LSG . . . . . .
MDL, HMDL, CMDL, CHMDL, MDLB, HMLDB; 800A; 3- and 4-pole; LSI, LSIG,
ALSI, ALSIG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Ground Fault Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance Mode Setting; ALSI and ALSIG . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TD012051EN . . . . . . . . 6
TD012052EN . . . . . . . . 7
TD012053EN . . . . . . . . 8
TD012054EN . . . . . . . . 9
Digitrip RMS 310 Electronic Trip Units
MDL, HMDL, CMDL, CHMD; 800A; 3- and 4-pole; LS and LSG . . . . . . . . . . . . . . . . . . . . . . SC-7204-99 . . . . . . . . 10
MDL, HMDL, CMDL, and CHMD; 800A 3- and 4-pole; LSI, LSIG, ALSI, ALSIG . . . . . . . . . . SC-6913-98 . . . . . . . 11
Ground Fault Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SC-6914-98 . . . . . . . . 12
MT Thermal/Magnetic Trip Unit
MDL, HMDL, MDLB, and HMDLB, 300-600A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SC-6911-98 . . . . . . . . 13
MDL, HMDL, MDLB, and HMDLB, 700-800A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SC-6912-98 . . . . . . . 14
Note:
Time/Current characteristic curves for Series C M-frame circuit breakers--voltages shown in curve headings are
maximum at which the breaker may be applied. Interrupting capacity of inidvidual breaker is tabulated on each curve.
Note:
The following curves are UL489 Listed for use in North America.
The following circuit breakers are derived from Eaton, Westinghouse, or Cutler-Hammer history.
Time Current Curves are engineering reference documents for application and coordination purposes only.
For field testing molded case circuit breakers, refer to NEMA AB 4 guidelines.
Time Current Curves TD012036EN
Series C
M-Frame

Effective December 2015
Notee: Unless noted below, all curves remain unchanged from their prior revision .
Revision
Curve Number
Changed trip labels on page 5
2
EATON www.eaton.com
Page
Date
Time Current Curves TD012036EN
Series C
M-Frame
Effective December 2015
Catalog Number Selection
This information is presented only as an aid to understanding catalog numbers.
It is not to be used to build catalog numbers for circuit breakers or trip units.
Table 1. Thermal-Magnetic Trip Unit
MT 3 800 T
Trip Unit Type
MT
MES
Number of Poles
2 = Two-pole
3 = Three-pole
Trip Unit
Ampere Rating
300 1
350 1
400
450
500
600
700
800
Suffix
T
V
LS
LSI
LSG
LSIG
= Thermal-magnetic
= 500C (thermal-magnetic trip units only)
= Digitrip RMS 310
= Digitrip RMS 310
= Digitrip RMS 310
= Digitrip RMS 310
Table 2. Circuit Breaker/Frame
MDL 3 800 F
Circuit Breaker/
Frame Type
Number of Poles
MDL, MDLB
HMDL, HMDLB
2 = Two-pole
3 = Three-pole
Circuit Breaker/Frame
Ampere Rating
300 1
350 1
400
450
500
600
700
800
Suffix
F
K
V
W
X
Y
= Frame only
= High magnetic molded case switch
= 500C (thermal-magnetic trip units only)
= Without terminals
= Load side terminals only
= Line side terminals only
Note
1 Thermal-magnetic only.
EATON www.eaton.com
3
Time Current Curves TD012036EN
Series C
M-Frame
Effective December 2015
Table 3. MDL Breaker Assembly
MDLB 3 800 F T36 B21 W
Terminals
Performance at 480 Vac
MDLB = 50 kAIC
HMDLB = 65 kAIC
CMDLB = 50 kAIC
100% rated
CHMDLB = 65 kAIC
100% rated
W = No terminals
Poles
3 = Three
Amperes
Features
800
Frame
Designation
F
Trip Unit
T33
T32
T35
T36
T38
T39
= 310+ Electronic LS
= 310+ Electronic LSI
= 310+ Electronic LSG
= 310+ Electronic LSIG
= 310+ Electronic LSI with Maintenance Mode
= 310+ Electronic LSIG with Maintenance Mode
Blank = No feature
B20 = High load alarm
B21 = Ground fault
alarm, with trip
B22 = Ground fault
alarm, no trip
ZG = Zone selective
interlocking
Table 4. MDL Electronic Trip Unit
MES 3 800 ALSIG B21
Trip
Unit Type
MES
Poles
Amperes
3 = Three
Features
800
Blank = No feature
B20 = High load alarm
B21 = Ground fault
alarm, with trip
B22 = Ground fault
alarm, no trip
ZG = Zone selective
interlocking
Trip Unit
= 310+ Electronic LS
= 310+ Electronic LSI
= 310+ Electronic LSG
= 310+ Electronic LSIG
= 310+ Electronic LSI with
Maintenance Mode
ALSIG = 310+ Electronic LSIG with
Maintenance Mode
LS
LSI
LSG
LSIG
ALSI
Table 5. MDL Frame Only
MDL 3 800 F
Performance at 480 Vac
MDL = 50 kAIC
HMDL = 65 kAIC
CMDL = 50 kAIC
100% rated
CHMDL = 65 kAIC
100% rated
Poles
3 = Three
Amperes
Frame Designation
800
F
Note
1
2
3
4
Maintenance Mode and ZSI are only available with LSI and LSIG trip units.
B21 and B22 features available only with LSG, LSIG and ALSIG trip units.
B2x suffixes cannot be combined with other B2x suffixes.
EATON www.eaton.com
Time Current Curves TD012036EN
Series C
M-Frame
Effective December 2015
ALSIG (With Maintenance Mode)
ALSI (With Maintenance Mode)
LSIG
LSG
LSI
LS
Figure 1. Digitrip 310+ Faceplates
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5
Time Current Curves TD012036EN
Series C
M-Frame
1 H our
2 Hours
Effective December 2015
0.5 0.7
10,000
9000
8000
7000
6000
5000
4000
1
2
Current in Multiples of (Ir)
3 4 5
7 10 12
20
30
Digitrip 310+ Circuit Breaker Time/Current Curves (Phase Current)
1.15
Series C M-Frame Circuit Breakers (800A)
Catalog Types: MDL, HMDL, CMDL, CHMDL, MDLB, HMLDB
3000
Trip Unit Types: 33 (LS), 35 (LSG)
2000
Available
Sensors
(Ir)/(In)
1000
900
800
700
600
500
400
Amperes
800A
A
B
C
D
E
F
G
H
Maximum Total
Clearing Time
300
320A
400A
450A
500A
600A
630A
700A
800A
Interrupting Rating
200
UL/CSA rms Sym. kA, 50/60 Hz
1 Minute
Breaker Type
100
90
80
70
60
50
40
Available Long Delay Time
(Seconds +0/–30%):
2*, 4*, 7*, 10, 12, 15*, 20, 24*
*Shown below at 6x
Time in Seconds
10
9
8
7
6
5
4
600V
25
35
2
Application frequency is 50/60 Hertz.
3There is a memory effect that can act to shorten the long delay. The memory effect comes
into play if a current above the long delay pickup value exists for a time and then is cleared
by the tripping of a downstream device or the circuit breaker itself. A subsequent overload
will cause the circuit breaker to trip in shorter time than normal. The amount of time
.
reduction is inverse to the amount of time that has elapsed since the previous overload.
Approximately five minutes is required between overloads to completely reset the memory.
15
Minimum Total
Clearing Time
50
65
1
Curve accuracy applies from –20°C to +55°C ambient . For possible continuous ampere
derating for ambient above 40°C, refer to Eaton . Temperatures above +88°C cause an
over-temperature protection trip.
24
20
480V
65
100
Notes:
.
.
30
240V
MDL, MDLB, CMDL
HMDL, HMDLB, CHMDL
4
The right portion of the curve is determined by the interrupting rating of the circuit breaker.
5
The left portion of the curve is shown as a multiple of the Long Delay Setting.
.
(Long Delay Pickup = 115% of Ir). Range is 110%–120%.
7
.
6
Total clearing times shown include the response times of the trip unit, the breaker opening,
and the interruption of the current.
4
3
2
.
3
2
1
0.9
0.8
0.7
0.6
0.5
0.4
7
The Short Delay Pick Up has 7 settings/positions, 2–8 Ir
8
Short Delay I2T band has a tolerance of ±15%.
9
Breakpoint back to FLAT response occurs at 8x IR for upper line of the I2T curve.
2
10For high fault current levels, an additional fixed instantaneous hardware override is provided
at 6800A (Tolerance ±15%).
4
5
7
0.3
0.3
8
0.2
6
I 2t Short Delay
(See Note 8)
0.2
.
Instantaneous
Override
(See Note 10)
67 ms
Application
Determines
End of Curve
0.1
0.09
0.08
0.07
0.06
0.05
0.04
0.03
0.03
See Note 9
0.02
0.02
0.01
0.5 0.7
1
2
3
4
5
7 10 12
20 30 40 50
Current in Multiples of (Ir)
70
100
2
3
4
I 2t Trip Style (LS and LSG)
5
7
10
20
30 40 50
Current in Multiples of (In)
70
Figure 2. Digitrip 310+ Trip Units (800A), Long Delay Response and Short Delay with I2T Response Curve and Override
(LS, LSG) - TD012051EN, October 2014
6
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0.01
100
Time in Seconds
0.1
0.09
0.08
0.07
0.06
0.05
0.04
Available Short Delay
Pickup Settings
2–8 x I r ±5%
(See Notes 7 and 10)
Time Current Curves TD012036EN
1 H our
2 Hours
Series C
M-Frame
10,000
9000
8000
7000
6000
5000
4000
Effective December 2015
0.5 0.7
1
2
Current in Multiples of (Ir)
3 4 5
7
10 12
20
30
Digitrip 310+ Circuit Breaker Time/Current Curves (Phase Current)
1.15
Series C M-Frame Circuit Breakers (800A)
Catalog Types: MDL, HMDL, CMDL, CHMDL, MDLB, HMLDB
3000
Trip Unit Types: 32 (LSI), 36 (LSIG), 38 (ALSI), and 39 (ALSIG)
2000
Available
Sensors
(Ir)/(In)
1000
900
800
700
600
500
400
A
B
C
D
E
F
G
H
Maximum Total
Clearing Time
300
Amperes
800A
320A
400A
450A
500A
600A
630A
700A
800A
Interrupting Rating
UL/CSA rms Sym. kA, 50/60 Hz
200
1 Minute
Breaker Type
Available
Long Delay Time
(Seconds +0/–30%):
2*, 4*, 7*, 10, 12, 15*, 20, 24*
*Shown below at 6x
100
90
80
70
60
50
40
.
24
Time in Seconds
20
65
100
480V
50
65
600V
25
35
Notes:
1
Curve accuracy applies from –20°C to +55°C ambient . For possible continuous ampere
derating for ambient above 40°C, refer to Eaton . Temperatures above +88°C cause an
over-temperature protection trip.
3There is a memory effect that can act to shorten the long delay. The memory effect comes
into play if a current above the long delay pickup value exists for a time and then is cleared
by the tripping of a downstream device or the circuit breaker itself. A subsequent overload
will cause the circuit breaker to trip in shorter time than normal. The amount of time
reduction is inverse to the amount of time that has elapsed since the previous overload.
Approximately five minutes is required between overloads to completely reset the memory.
.
15
MinimumTotal
ClearingTime
4
The right portion of the curve is determined by the interrupting rating of the circuit breaker.
.
5
The left portion of the curve is shown as a multiple of the Long Delay Setting .
(Long Delay). Range is 110%–120%.
7
6
Total clearing times shown include the response times of the trip unit, the breaker
Pickup = 115% of Ir opening, and the interruption of the current.
.
4
3
2
1
0.9
0.8
0.7
0.6
0.5
0.4
240V
2
Application frequency is 50/60 Hertz.
30
10
9
8
7
6
5
4
MDL, MDLB, CMDL
HMDL, HMDLB, CHMDL
.
Available Short
Delay Pickup
Settings 2–8,
x I r ±5%
(See Note 7)
2
7
The Short Delay Pick Up has 7 settings/positions, 2–8 IR
8
For high fault current levels, an additional fixed instantaneous hardware override is provided
at 5620A (Tolerance ±15%).
2
4
6
3
8
5
0.4
300 ms
(P, Q, R)
0.3
7
120 ms
(M, N, O)
0.1
0.09
0.08
0.07
0.06
0.05
0.04
Application
Determines
End of Curve
Inst.
(J, K, L)
0.2
0.1
0.09
0.08
0.07
0.06
0.05
0.04
0.03
0.03
0.02
0.02
0.01
0.5 0.7
1
2
3 4 5
7
10 12
20
30 40 50 70 100
2
3 4 5
7
10
20
30 40 50
Current in Multiples of (Ir)
Current in Multiples of (In)
Adjustable Flat Trip Style (LSI, LSIG, ALSI, ALSIG)
Time in Seconds
0.2
0.3
Instantaneous
Override (See Note 8)
0.01
70 100
Figure 3. Digitrip 310+ Trip Units (800A), Long Delay Response and Short Delay with Flat Response Curve and Override
(LSI, LSIG, ALSI, ALSIG) - TD012052EN, October 2014
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7
Time Current Curves TD012036EN
Series C
M-Frame
Effective December 2015
10,000
9000
8000
7000
6000
5000
4000
0.1
0.2
0.3 0.4 0.5
0.7
1
2
Digitrip 310+ Circuit Breaker Time/Current Curves (Ground Current)
Series C M-Frame Circuit Breakers (800A)
Catalog Types: MDL, HMDL, CMDL, CHMDL, MDLB, HMLDB
3000
Trip Unit Types: LSG, LSIG, ALSIG
2000
Notes:
Curve accuracy applies from –20°C to +55°C ambient. For possible continuous ampere derating
for ambient above 40°C, refer to Eaton.
1000
900
800
700
600
500
Digitrip RMS 310 trip units are suitable for functional field testing with test kit Cat. No. STK2.
For field testing using primary injection methods, follow NEMA publications
400
300
1 Minute
200
100
90
80
70
60
50
40
Time in Seconds
30
20
10
9
8
7
6
5
Ground Fault Pickup Settings
(Tolerance ±10%)
4
3
2
0.2X
1
0.9
0.8
0.7
0.6
0.5
0.4
0.4X
0.6X
1X
0.3X
0.8X
300 ms
(L, O, R)
0.3
0.2
120 ms
(K, N, Q)
0.1
0.09
0.08
0.07
0.06
0.05
Inst.
(J, M, P)
0.04
0.03
0.02
0.01
0.1
0.2
0.3 0.4 0.5 0.7 1
Ground Current in Multiple of (In)
2
Figure 4. Ground Fault Delay Response Curve (LSG, LSIG, ALSIG) - Curve Number TD012053EN
8
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Time Current Curves TD012036EN
Series C
M-Frame
Effective December 2015
Notes:
Digitrip 310+ Circuit Breaker Time/Current Curves
1
The Maintenance Mode feature must be ENABLED via application of
24 Vdc for these curves to apply. The blue LED is lit when in Maintenance Mode.
Maintenance Mode Setting
Trip Unit Types: 38 (ALSI) and 39 (ALSIG)
2
The end of the curve is determined by the interrupting rating of the circuit breaker.
Series C M-Frame Trip Unit Nameplates
3Total clearing times shown include the response times of the trip unit,
the breaker opening, and the interruption of the current.
4
Nominal Values (Pickup) (Tolerance is ±15%) 2.5 x In.
5
The total clearing times shown are conservative and consider the maximum response
time of the trip unit, the circuit breaker opening, and the interruption of the current in
the worst case conditions such as: maximum rated voltages, single-phase interruption,
and minimum power factor. Faster clearing times are possible depending on the specific
system conditions.
ALSI
Contact Eaton for additional information.
.
NO
C
ALSIG
Left Side of Breaker
Black
Ir = Continuous Current Setting or Rating Plug Value, Is = Current Sensor Frame Rating,
In = Rating Plug Value, Ig = Ground Current Pickup Multiplier, Ii = Instantaneous Override Pickup.
Yellow
24 Vdc
Blue
Relay Wiring
Red
Maintenance Mode Trip
10
9
8
7
6
5
4
3
2
1
.9
.8
.7
.6
2.5
.5
TIME IN SECONDS
.4
.3
.2
.1
.09
.08
.07
.06
Application
determines
end of curve
.05
.04
.03
.02
40
50
30
20
7
8
9
10
5
6
4
3
2
.6
.7
.8
.9
1
.5
.01
Current in Multiples of Rating ( In )
Figure 5. Maintenance Mode Setting (ALSI, ALSIG) - Curver Number - TD012054EN, October 2014
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9
Time Current Curves TD012036EN
Series C
M-Frame

Effective December 2015
Types MDL, HMDL, CMDL, and CHMDL Equipped with Type MES Digitrip RMS 310 Trip Units, Types MES3800LS and MES3800LSG
CURRENT IN MULTIPLES OF RATING PLUG AMPERES (In )
.5 .6 .7 .8 .9 1
10,000
2
3
4
5
6 7 8 910
Circuit Breaker Time/Current Curves (Phase Current)
20
1 HOUR
2 HOURS
Series C M-Frame Circuit Breakers
Equipped With Type MES Digitrip RMS 310 Trip Units
5,000
Catalog Types: MES3800LS and MES3800LSG Digitrip RMS 310 Trip Units for use
with Circuit Breaker Types MDL, HMDL, CMDL and CHMDL 3 Poles.
1.15
3,000
Fixed Short Delay Time
Digitrip RMS 310 Rating Plug
2,000
Cat.
Standard Fixed
Rating Plug
Push to Trip
In
Engaged
Typical Trip Unit Nameplate
Test
Short Delay
Pickup x I n
4
3
5
2
6
7
Digitrip RMS 310
Trip Unit
40o C Ambient
8
Remove
1,000
Available Rating Plugs
500
300
Long Delay ➀
Maximum Total
Clearing Time
200
1 MINUTE
100
Long Delay ➀
Minimum Total
Clearing Time
Ampere
Rating
(In)
Type
800
700
600
500
400
400, 500, 600, 800
Fixed
Fixed
Fixed
Fixed
Fixed
Adjustable
Interrupting Rating
50
30
Short Delay
Pick Up
Settings
(Tolerance
+ 10%)
3X
2X
20
UL/CSA rms Sym. kA, 50/60 Hz
240V
480V
600V
MDL, MDLB, CMDL, CMDLB
HMDL, HMDLB, CHMDL, CHMDL
65
100
MDL, MDLB, CMDL, CMDLB
HMDL, HMDLB, CHMDL, CHMDL
4X
50
65
25
35
IEC 60947-2 rms Sym. kA, 50/60 Hz
240V
380/415V
690V
Icu
65
100
Ics
65
100
Icu
50
70
Ics
50
50
Icu
20
25
Ics
10
13
Utilization Category A
UIMP = 8 kV
Notes:
Digitrip RMS 310 trip units are suitable for functional field testing with test kit Cat. No. STK2.
For field testing using primary injection methods, follow NEMA AB4 publications.
3
6X
1
There is a memory effect that can act to shorten the long delay. The memory effect comes
into play if a current above the long delay pick-up value exists for a time and then is cleared
by the tripping of a downstream device or the circuit breaker itself. A subsequent overload
will cause the circuit breaker to trip in shorter time than normal. The amount of time delay
reduction is inverse to the amount of time that has elapsed since the previous overload.
Approximately five minutes is required between overloads to completely reset the memory.
8X
5X
Calibration response in short delay pick-up range is same for 1, 2 or 3 poles in series.
2
.5
1Curve accuracy applies from –20°C to +55°C ambient. For possible continuous ampere
derating for ambient above 40°C, refer to Eaton.
.3
2For high fault current levels a fixed instantaneous override is provided at 6800A.
(Tolerance ±15%).
7X
TIME IN SECONDS
Short Delay
Pickup Range
Amperes
1600-6400
1400-5600
1200-4800
1000-4000
800-3200
800-6400
Breaker Type
Breaker Type
10
5
Rating Plug
Catalog
Number
8MES800T
8MES700T
8MES600T
8MES500T
8MES400T
A8MES800T1
3The end of the curve is determined by the interrupting rating of the circuit breaker.
See above tabulation.
.2
4 Long delay pickup is 115% of In, +/- 15%.
.1
.1
.05
.05
Fixed Instantaneous
Override ➁
.04
.03
.02
.02
SECONDS
.03
.01
Interrupting
Rating
Determines
End of
Curve ➂
.01
.005
.003
50,000
40,000
30,000
.001
100,000
CURRENT IN MULTIPLES OF RATING PLUG AMPERES (In)
20
20,000
6 7 8 910
10,000
5
5000
4
4000
3
3000
2
2000
.001
.5 .6 .7 .8 .9 1
1000
.002
CURRENT IN AMPERES
Figure 6. MDL, HMDL, CMDL, and CHMDL, types MES3800LS and MES3800LSG - Curve Number SC-7204-99, June 2007
10
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Time Current Curves TD012036EN
Series C
M-Frame
Effective December 2015
Types MDL, HMDL, CMDL, and CHMDL Equipped with Type MES Digitrip RMS 310 Trip Units, Types MES3800LSI and MES3800LSIG
Circuit Breaker Time/Current Curves (Phase Current)
Series C M-Frame Circuit Breakers
Equipped With Type MES Digitrip RMS 310 Trip Units
Catalog Types: MES3800LSI and MES3800LSIGDigitrip RMS 310 Trip Units for use
with Circuit Breaker Types MDL, HMDL, CMDL, CHMDL 3 Poles.
Adjustable Short Delay Time
Digitrip RMS 310 Rating Plug
CURRENT IN MULTIPLES OF RATING PLUG AMPERES (In)
.5 .6 .7 .8 .9 1
2
3
4
5
6 7 8 9 10
Engaged
2
Test
Time
MIsec
200
100
I
8
300
Digitrip RMS 310
Trip Unit
40o C Ambient
3
Remove
5,000
1 HOUR
Push to Trip
In
20
2 HOURS
10,000
Typical Trip Unit Nameplate
Short Delay
Pickup x I n
5
4
6
7
Cat.
Available Rating Plugs
1.15
3,000
2,000
Standard Fixed
Rating Plug
1,000
500
200
1 MINUTE
Long Delay ➀
Maximum Total
Clearing Time
Long Delay ➀
Minimum Total
Clearing Time
800
700
600
500
400
400, 500, 600, 800
Fixed
Fixed
Fixed
Fixed
Fixed
Adjustable
Rating Plug
Catalog
Number
8MES800T
8MES700T
8MES600T
8MES500T
8MES400T
A8MES800T1
UL/CSA rms Sym. kA, 50/60 Hz
240V
480V
600V
MDL, MDLB, CMDL, CMDLB
HMDL, HMDLB, CHMDL, CHMDL
65
100
Breaker Type
IEC 60947-2 rms Sym. kA, 50/60 Hz
240V
380/415V
690V
2X
20
50
65
Icu
65
100
Ics
65
100
25
35
Icu
50
70
Ics
50
50
Icu
20
25
Ics
10
13
Utilization Category A
UIMP = 8 kV
Notes:
Short Delay
Pickup
Settings
(Tolerance
+10%)
Short Delay
Pickup Range
Amperes
1600-6400
1400-5600
1200-4800
1000-4000
800-3200
800-6400
Breaker Type
MDL, MDLB, CMDL, CMDLB
HMDL, HMDLB, CHMDL, CHMDL
50
30
Digitrip RMS 310 trip units are suitable for functional field testing with test kit Cat. No. STK2.
For field testing using primary injection methods, follow NEMA AB4 publications.
Calibration response in short delay pick-up range is same for 1, 2 or 3 poles in series.
10
4X
There is a memory effect that can act to shorten the long delay. The memory effect comes
into play if a current above the long delay pick-up value exists for a time and then is cleared
by the tripping of a downstream device or the circuit breaker itself. A subsequent overload
will cause the circuit breaker to trip in shorter time than normal. The amount of time delay
reduction is inverse to the amount of time that has elapsed since the previous overload.
Approximately five minutes is required between overloads to completely reset the memory.
6X
5
3
1Curve accuracy applies from –20°C to +55°C ambient. For possible continuous ampere
derating for ambient above 40°C, refer to Eaton.
8X
2
2For high fault current levels a fixed instantaneous override is provided at 6800A.
(Tolerance ±15%).
7X
TIME IN SECONDS
Type
Interrupting Rating
300
100
Ampere
Rating
(In)
1
3The end of the curve is determined by the interrupting rating of the circuit breaker.
See above tabulation.
5X
3X
.5
4Long delay pickup is 115% of In, +/- 5%.
300 ms
.3
200 ms
.2
100 ms
.1
.1
I
.05
.05
Fixed Instantaneous
Override ➁
.04
.03
.02
SECONDS
.03
.02
.01
Interrupting
Rating
Determines
End of
Curve ➂
.01
.005
.003
100,000
50,000
40,000
.001
30,000
20
20,000
6 7 8 9 10
10,000
5
5000
4
4000
3
3000
2
CURRENT IN MULTIPLES OF RATING PLUG AMPERES (In)
2000
.001
.5 .6 .7 .8 .9 1
1000
.002
CURRENT IN AMPS
Figure 7. MDL, HMDL, CMDL, and CHMDL, types MES3800LSI and MES3800LSIG – Curve Number - SC-6913-98, June 2007
EATON www.eaton.com
11
Time Current Curves TD012036EN
Series C
M-Frame

Effective December 2015
Types MDL, HMDL, CMDL, and CHMDL Equipped with Type MES Digitrip RMS 310 Trip Units, Ground Fault Protection
1 HOUR
16000
1120
1280
1440
1600
960
800
640
480
320
2 HOURS
10,000
160
GROUND CURRENT-AMPERES
Circuit Breaker Time/Current Curves (Ground Current)
5,000
Series C M-Frame Circuit Breakers
3,000
Equipped With Type MES Digitrip RMS 310 Trip Units
for Ground Fault Protection
2,000
Catalog Types: MES3800LSG and MES3800LSIG Digitrip RMS 310 Trip Units for use
with Circuit Breaker Types MDL, KMDL, CMDL, CHMDL.
1,000
Typical Trip Unit Nameplate
Fixed Short Delay Time
Digitrip RMS 310 Rating Plug
Cat.
Push to Trip
In
Engaged
500
Short Delay
Pickup x I n
4
5
2
Ground Fault
Pickup x I g
6
7
3
3
2
4
1
8
5
Time
MIsec
300
150
I
Test
500
Digitrip RMS 310
Trip Unit
40o C Ambient
I g = 160A
Remove
Typical Trip Unit Nameplate
Adjustable Short Delay Time
300
Digitrip RMS 310 Rating Plug
Cat.
Push to Trip
In
200
Engaged
Short Delay
Pickup x I n
4
2
5
6
7
8
Time
MIsec
200
100
I
300
3
Ground Fault
Pickup x I g
3
2
1
4
5
Time
MIsec
300
150
I
Test
500
I g = 160A
Digitrip RMS 310
Trip Unit
40o C Ambient
Remove
1 MINUTE
100
Notes:
Curve accuracy applies from –20°C to +55°C ambient. For possible continuous ampere derating
for ambient above 40°C, refer to Eaton.
50
Digitrip RMS 310 trip units are suitable for functional field testing with test kit Cat. No. STK2. For
field testing using primary injection methods, follow NEMA publication (AB4).
30
1xI G
20
3xI G
4xI G
10
5
Ground Fault Pickup
Settings
(Tolerance + 10%
Except + 20% on
1xI G Setting)
2xI G
3
5xI G
TIME IN SECONDS
2
1
500 ms
.5
300 ms
.3
.2
150 ms
.1
I
.05
.03
.02
.01
.005
.003
.002
.001
1
2
3
4
5
6
7 8 910
100
GROUND CURRENT-IN MULTIPLES OF I g = 160A
Figure 8. MDL, HMDL, CMDL, and CHMD Ground Fault Protection - Curve Number SC-6914-98, June 2007
12
EATON www.eaton.com
Time Current Curves TD012036EN
Series C
M-Frame
Effective December 2015
Types MDL, HMDL, MDLB, and HMDLB Equipped with Type MT Thermal-Magnetic Trip Unit, 300 to 600 Amperes
6000
7000
8000
9000
10,000
5000
4000
3000
2000
600
700
800
900
1000
500
400
300
200
Series C M-Frame Circuit Breakers
10,000
Equipped With Type MT Thermal-Magnetic Trip Unit
Catalog Types: MDL, HMDL, MDLB, HMDLB Circuit Breakers, 2 and 3 Poles.
5,000
5,000
3,000
For application and coordination purposes only. Thermal calibration based on 40°C ambient, cold
start. Connected with four (4) feet of rated wire (75°C) per terminal. Tested in open air with
current in all poles. Instantaneous calibration based on single-pole3,000
tests.
2,000
Maximum Voltage: 600V, AC (50/60 Hz) 250V, DC
1 HOUR
1 HOUR
2 HOURS
70
80
90
100
Circuit Breaker Time/Current Curves
2 HOURS
10,000
60
50
CURRENT IN PERCENT OF BREAKER TRIP UNIT RATING (In )
2,000
Breaker Rating
1,000
500
Instantaneous Trip Amperes
(See Figure Below)
300 - 600
500 to 1000% of trip unit rating (DC values are approximately 40% higher)
Interrupting Rating
Maximum Single
Pole Trip Times
at 25 o C 1
300
Breaker Type
200
Minimum
Maximum
100
500
UL/CSA rms Sym. kA, 50/60 Hz
240V
480V
600V
65
100
Breaker Type
IEC 60947-2 rms Sym. kA, 50/60 Hz
240V
380V
415V
100
Icu
65
100
Ics
65
100
25
35
Icu
50
70
Ics
50
50
50
kA, DC
250V
Ics
10
13
20
20
10
10
30
For additional information on the trip unit, see IL 29C607.
20
22
25
200
Icu
20
25
Utilization Category A
UIMP = 8 kV
Notes:
30
50
65
kA, DC
250V
300
MDL, MDLB
HMDL, HMDLB
MDL, MDLB
HMDL, HMDLB
50
1,000
1 MINUTE
1 MINUTE
Rated
Amperes (In)
20
1Single pole data at 25°C based on NEMA Procedures (AB 4) for verifying performance of
molded case circuit breakers.
Typical
Trip Unit
Nameplate
10
10
7.5
10
7.5
C Thermal
Magnetic
Trip Unit
5
5
5
10
5
Amps
(I n)
Magnetic
Multiples OfnI
3
10
40oC
Cat.
No.
5
3
2
2
5X
+20%
1
10X
Individual Pole
Adjustments
.5
+10%
1
.5
Adjustable Magnetic Trip
.3
.3
.2
.2
.1
.1
.05
.05
.03
Maximum Interrupting Time
.03
.02
.02
.01
.01
Interrupting Rating
Determines End of
Curve
.005
.005
60,000
70,000
80,000
90,000
100,000
CURRENT IN PERCENT OF BREAKER TRIP UNIT RATING (In)
50,000
40,000
30,000
20,000
6000
7000
8000
9000
10,000
5000
4000
3000
2000
500
600
700
800
900
1000
400
.001
300
.001
200
.002
60
.003
.002
70
80
90
100
.003
50
TIME IN SECONDS
TIME IN SECONDS
7.5
Push to Trip
Figure 9. MDL, HMDL, MDLB, and HMDLB, 300-600A - Curve Number SC-6911-98, June 2007
EATON www.eaton.com
13
Time Current Curves TD012036EN
Series C
M-Frame
Effective December 2015
Types MDL, HMDL, MDLB, and HMDLB Equipped with Type MT Thermal-Magnetic Trip Unit, 700 and 800 Amperes
6000
7000
8000
9000
10,000
5000
4000
3000
2000
600
700
800
900
1000
500
400
300
200
Circuit Breaker Time/Current Curves
Series C M-Frame Circuit Breakers
5,000
5,000
1 HOUR
1 HOUR
2 HOURS
10,000
2 HOURS
10,000
60
70
80
90
100
50
CURRENT IN PERCENT OF BREAKER TRIP UNIT RATING (In)
Equipped With Type MT Thermal-Magnetic Trip Unit
3,000
Catalog Types: MDL, HMDL, MDLB, HMDLB Circuit Breakers,
2 and 3 Poles.
3,000
For application and coordination purposes only. Thermal calibration
based on 40°C ambient, cold
2,000
start. Connected with four (4) feet of rated wire (75°C) per terminal. Tested in open air with
current in all poles. Instantaneous calibration based on single-pole tests.
2,000
Maximum Voltage: 600V, AC (50/60 Hz) 250V, DC
1,000
1,000
Breaker Rating
500
Maximum Single
Pole Trip Times
at 25 o C 1
300
Instantaneous Trip Amperes
(See Figure Below)
700 - 800
400 to 800% of trip unit rating (DC values are approximately 40% higher)
Maximum
100
UL/CSA rms Sym. kA, 50/60 Hz
240V
480V
600V
50
MDL, MDLB
HMDL, HMDLB
65
100
Breaker Type
IEC 60947-2 rms Sym. kA, 50/60 Hz
50
240V
380V
415V
Icu
65
100
MDL, MDLB
HMDL, HMDLB
30
25
35
Ics
65
100
Icu
50
70
Ics
50
50
Notes:
kA, DC
250V
100
Icu
20 30
25
Utilization Category A
UIMP = 8 kV
20
Typical
Trip Unit
Nameplate
50
65
200
22
25
1 MINUTE
1 MINUTE
300
Breaker Type
10
500
Interrupting Rating
200
Minimum
Rated
Amperes (In)
Ics
10
13
kA, DC
250V
20
20
10
10
20
For additional information on the trip unit, see IL 29C607.
10
1Single pole data at 25°C based on NEMA Procedures (AB 4) for verifying performance of
molded case circuit breakers.
5
5
6
6
Thermal
Magnetic
Trip Unit
3
8
2
8
4
8X
4X
+ 20%
.5
8
Amps
(I n)
Magnetic
Multiples OfnI
1
o
C
4
2
Cat.
No.
+ 10%
1
Individual Pole
Adjustments
.5
Adjustable Magnetic Trip
.3
.3
.2
.2
.1
.1
.05
.05
.03
Maximum Interrupting Time
.03
.02
.02
.01
.01
Interrupting Rating
Determines End of
Curve
.005
.005
60,000
70,000
80,000
90,000
100,000
50,000
40,000
30,000
20,000
6000
7000
8000
9000
10,000
5000
4000
3000
2000
600
700
800
900
1000
500
400
.001
300
.001
200
.002
60
70
80
90
100
.003
.002
50
.003
CURRENT IN PERCENT OF BREAKER TRIP UNIT RATING (In)
Figure 10. MDL, HMDL, MDLB, and HMDLB, 700-800A - Curve Number SC-6912-98, June 2007
14
3
Push to Trip
4
EATON www.eaton.com
TIME IN SECONDS
TIME IN SECONDS
6
Series C
M-Frame
Time Current Curves TD012036EN
Effective December 2015
EATON www.eaton.com
15
Time Current Curves TD012036EN
Effective December 2015
Series C
M-Frame

Eaton
1000 Eaton Boulevard
Cleveland, OH 44122
United States
Eaton.com
© 2014 Eaton
All Rights Reserved
Printed in USA
Publication No. TD012036EN / KDC
April 2014
Eaton is a registered trademark.
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of their respective owners.