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EATON CORPORATION Cutler-Hammer
Information Sheets 70C1454H02
1.0 General
Per the above WARNING, it is highly recommended that
maintenance be conducted on electrical equipment
including circuit breakers with the system de-energized.
For situations that arise where this is not possible, the
Maintenance Mode function of the Digitrip 520MC family
(cat 5ARMLSI, 5ARMLSIG, 5ARMLSIA) can reduce Arc
Flash incident energy that is generated on a fault condi-
tion. This is accomplished by a analog trip circuit which,
when armed, provides a fast acting response to the fault.
The reduced arc condition will occur only in devices
downstream of the trip unit in Maintenance Mode. This is
separate from the normal system protection setting of
Instantaneous. The Maintenance Mode is located in the
upper, white portion of the unit.
2.0 Maintenance Mode Settings
The Maintenance Mode Settings (labeled R5, R4, R3, R2,
R1) provide the Arc Flash Reduction setting. R5 is the
Maximum reduction setting which correlates to the lowest
pickup value.
Nominal Trip current of Maintenance Mode Settings
Setting R5 2.5x Rating Plug Amperes
Setting R4
4.0x Rating Plug Amperes
Setting R3
6.0x Rating Plug Amperes
Setting R2
8.0x Rating Plug Amperes
Setting R1
10x Rating Plug Amperes
3.0 Arming Maintenance Mode
There are three ways to arm the Maintenance Mode Arc
Flash Reduction setting. One method is locally via the two
position switch in the Maintenance Mode section of the
trip unit. Turning the switch to the ON position will arm
the setting selected. A blue LED confirms that the
function is on.
WARNING
ONLY CERTIFIED AND COMPETENT PERSONNEL
SHOULD ATTEMPT TO INSTALL OR MAINTAIN
POTENTIALLY HAZARDOUS EQUIPMENT.
DO NOT ATTEMPT TO INSTALL OR PERFORM
MAINTENANCE ON EQUIPMENT WHILE IT IS
ENERGIZED. DEATH OR SEVERE PERSONAL INJURY
CAN RESULT FROM CONTACT WITH ENERGIZED
EQUIPMENT. ALWAYS VERIFY THAT NO VOLTAGE IS
PRESENT BEFORE PROCEEDING. ALWAYS FOLLOW
SAFETY PROCEDURES.
EATON IS NOT LIABLE FOR THE MISAPPLICATION
OR MISINSTALLATION OF ITS PRODUCTS.
CAUTION
A FLASH HAZARD ANALYSIS SHOULD BE DONE TO
DETERMINE PERSONAL PROTECTIVE EQUIPMENT
REQUIREMENTS
CAUTION
OBSERVE ALL RECOMMENDATIONS, NOTES, CAU-
TIONS, AND WARNINGS RELATING TO THE SAFETY
OF PERSONNEL AND EQUIPMENT. OBSERVE AND
COMPLY WITH ALL GENERAL AND LOCAL HEALTH
AND SAFETY LAWS, CODES, AND PROCEDURES.
