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Instructions for the Digitrip RMS 310 3-Pole and 4-Pole Trip Unit Installation 

and Operation with L-Frame and MDL-Frame Series C Circuit Breakers 

Table 

of 

Contents 

Description 

Page 

General Information 

............................................... 

1.1 

Protection 

.............................................................. 

2.0 

UL Listed Devices 

.................................................. 

3.0 

Installation 

............................................................. 

3.1 

Preparation (All Trip Units) 

..................................... 

3.2 

4-Pole Trip Unit Installation 

..................................... 

3.3 

Ground Fault Trip Unit Installation 

.......................... 

3.3.1 

General 

.................................................................. 

3.3.2 

Installation 

............................................................. 

3.4 
3.5 
4.0 
4.1 
4.2 
4.3 
4.4 
5.0 
5.1 
5.2 
5.3 
5.4 
5.5 
5.6 
6.0 
6.1 
6.2 

3-Pole (Non-Ground Fault) Trip Unit Installation 

..... 

Final Installation Instructions (All Trip Units) 

........... 

Principle of Operation 

............................................ 

General 

.................................................................. 

Overload Trip 

......................................................... 

Short 

Trip 

.............................. 

Ground Fault Protection 

......................................... 

Protection Settings 

................................................. 

General 

.................................................................. 

Short Delay Pick-up Settings 

................................. 

Short Delay Time Settings 

..................................... 

Instantaneous Pickup Setting 

................................ 

Ground Fault Pick-up Setting 

................................. 

Ground Fault Time Settings 

................................... 

Testing 

................................................................... 

Functional Field Testing 

......................................... 

Performance Testing for Ground Fault Trip Units 

.... 

6.2.1 

Code Requirements 

............................................... 

6.2.2 

Standards Requirements 

....................................... 

6.2.3 

General Test  Instructions 

....................................... 

7.0 

Rating Plug 

.......................................................... 

12 

8.0 

References 

.......................................................... 

12 

8.1 

Series C L-Frame Molded Case 
Circuit Breakers 

................................................... 

12 

8.2 

Internal Accessories 

............................................ 

12 

PRESENT BEFORE PROCEEDING 

AND ALWAYS FOLLOW GENERALLY ACCEPTED 
SAFETY PROCEDURES. 

MISAPPLICATION 

OR MISINSTALLATION 

OF ITS 

PRODUCTS. 

CUTLER-HAMMER 

IS 

NOT LIABLE 

The user is cautioned to observe all recommendations, 
warnings, and cautions relating to the safety of personnel 
and equipment as well as all general and local health and 
safety laws, codes, and procedures. 

The recommendations and information contained herein 
are based on Cutler-Hammer experience and judgement, 

but should not be considered to be all-inclusive or cover- 
ing every application or circumstance which may arise. If 
any questions arise, contact Cutler-Hammer for further 
information or instructions. 

Fig. 

Digitrip RMS 310 

Unit 

for 3-Pole L-Frame 

MDL Frame Series C Circuit Breaker 

GENERAL INFORMATION 

WARNING 

DEATH, SEVERE PERSONAL INJURY, 

OR 

SUBSTANTIAL  PROPERTY DAMAGE CAN RESULT 

FROM CONTACT WITH ENERGIZED EQUIPMENT. DO 
NOT ATTEMPT INSTALL 

OR 

PERFORM 

MAINTENANCE ON EQUIPMENT WHILE IT 

IS 

ENERGIZED. ALWAYS VERIFY THAT NO VOLTAGE 

IS 

1.1 

Protection 

The Digitrip RMS 

31 0, 

illustrated in Figure 

1, 

is an elec- 

tronic trip unit that incorporates a microprocessor-based 
custom application specific integrated circuit design for 

use with Series C L-Frame and MDL Frame Molded Case 
Circuit Breakers. 

The Digitrip RMS 

310 

provides true RMS current sensing 

for proper correlation with thermal characteristics of 
conductors and equipment. Interchangeable rating plugs 

Effective 

March 2003 Supersedes I.L. 29C615D dated July 1998 

I.L. 29C615E

Courtesy of NationalSwitchgear.com

Summary of Contents for Digitrip RMS 310

Page 1: ...TION OR MISINSTALLATION OF ITS PRODUCTS CUTLER HAMMER IS NOT LIABLE FORTHE The user is cautioned to observe all recommendations warnings and cautions relatingto the safety of personnel and equipment a...

Page 2: ...ing steps Note If required internal accessory installation should be done before the circuit breaker is mounted and connected Refer to individualaccessory instruc tion leaflets Make sure that the trip...

Page 3: ...ed but no phaseto neutral loadsare used the neutralcurrent sensor is not necessary Inthat case the white and grey leadson the trip unit should be cut off before installation If the system neutralis gr...

Page 4: ...OURCE LOAD Aux Iiaryswitch shown m the Breaker Canlacis Open pmilmn Fig 6 COVER SCREWS TORQUE 20 22 9 9 1 b Fig 7a MDL Trip Unit Installation E VN Effective March 2003 I L 29C615E Courtesy of National...

Page 5: ...also remove the load end trip unit mounting screws from the frame fig 7a Note The two trip unit outer retaining screws may be placed in the trip unit conductor holes at this time If preferred the 5 1...

Page 6: ...heck manual tripping of the circuit breaker Fig 9 Cover Screw Installation Positions Note Before attempting to install the rating plug the arrow in the Push to Trip button portion of the plug must be...

Page 7: ...es LSI LSIE LSIP and LSlG unlessthe instantaneous I setting is selected 4 4 Ground Fault Protection When selected ground fault pick up and time delay settings shown inTable 1 2 allow selective ground...

Page 8: ...I Ih 1 Ilh 5 Short Delay Pick up Multiples of Rated Cu Current irrent Fig 12 1 Short Delay TripCurrent Adjustment and Curve Details Fig 12 2Short Delay TripCurrentand Short Delay Trip Time Adjustment...

Page 9: ...rounding points of the system shall be verified to determinethat ground paths do not exist that would bypass the sensors The use of high voltagetesters and resistancebridges may be used i 3 0 0 8 Rati...

Page 10: ...e Current Limiting Resistor if required Fig 14 3 Connectionsfor GroundFault No Trip Test with a Three WireSystem Source Load Nl Current Limiting Resistor if required Fig 14 2 Connectionsfor GroundFaul...

Page 11: ...hose in Charge of the Building s Electrical Installation in order to be available to the Authority having Jurisdiction Test Date Circuit Breaker Number Results Tested By Fig 16 TypicalPerformanceTestR...

Page 12: ...ustable rating plugs Table 1 2 the primary current carrying conductors used with the breaker must be sized to correspond with the maximumsetting of the rating plug in accordance with National Electric...

Page 13: ...fourth pole Fourth pole unprotected 0 Fixed rating plugs available see Table 1 2 0 Optional four setting adjustable rating plugs available seeTable 1 2 8 Using trip unit with adjustable short delay t...

Page 14: ...ck upO Ground Fault Pick up Adjustable Ground FaultTime Delay Fixed rating plugs available Trip Unit Fixed Rating Plugs Amoere Ratina 600A 630A 800A 300A 350A 400A 500A 600A I 300A 315AO 350A 400A 500...

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