Non-Standard Conditions - Mitsubishi Electric C Series Handling And Maintenance

3.3 Non-standard conditions

When operated under different conditions from the normal service conditions, it is necessary to take
the following measures against the operating conditions.
Even with such measures taken, however, service life may become shorter in some cases.
Special environment
Low
tempera-
ture
Freezing warehouse,
low temperature room
High
tempera-
ture, high
humidity
Chemical plant
Corrosive
gas, salt
content
Chemical plant, Oil
refining plant
Dust,
vapour
Cement plant, spinning
mill, gravel pit
Note 1. SHT and UVT of internal accessories are excluded.
2. Electronic types are excluded.
Circuit breaker for
special environment
This breaker is so designed to enable
Circuit breaker for
power supply, switching, and short cir-
low temperature
cuit breaking at -40°C. The operating
characteristics change at low tempera-
ture as they are adjusted for the refer-
ence ambient temperatur.
(For storing, consider the use is pos-
sible up to -50°C at the lowest.)
• Moisture-fungus treatment of the 1st
kind
In addition to special surface
Circuit breaker for
treatment and special materials,
moisture-fungus
corrosionproof treatment is applied.
treatment
• Moisture-fungus treatment of the 2nd
kind
Special surface treatment is applied
and special materials are used. In hu-
mid environment, insulation strength
and other electrical performances
tend to be lowered. The special sur-
face treatment and the special ma-
terials are used to avoid such dete-
rioration.
• In the environment containing much
corrosive gas (gas concentration
level up to the note *given below), it
is advisable to use MCCB of added
corrosion resistive specifications.
F o r t h e b r e a k e r s o f a d d e d
corrosionproof type, corrosionproof
Added corrosion
plating is applied to the metal parts.
resistive circuit
• Where concentration of corrosive gas
breaker
exceeds the level stated below, it is nec-
essary to use MCCB of added corro-
sion resistive type being enclosed in a
waterproof type enclosure or in any en-
closure of protective structure.
* Concentration of corrosive gas al-
lowed by the Safety and Health Stan-
dard:
(Ex.) H
Where concentration of corrosive gas
is about 1/100 of the noted level and
H S (0.01 ppm), the standard MCCB
2
can be used.
Expected service life (MTTF) will be
less than 15 years.
Enclosed circuit breaker of dustproof (type I) or waterproof (type W) is advis-
Enclosed circuit
able for places where much dust or vapour is contained.
breaker For installing circuit breakers in explosionproof enclosure, use non-ammonia
mould product.
Specifications
S (10 ppm), HCI (5 ppm),
2
CI (1 ppm), SO (5 ppm),
2 2
NH (25 ppm) - (Japan Industrial
3
Health Association, since 1973)
Applicable model
MCCB ELCB
• 1600 A frame of
S - s e r i e s a n d
lower
• All models of C-
–
series
• Moisture-fungus
(Note 2)
treatment of the
1st kind (Note 2)
Front connection,
All models of S-
rear connection,
and C- series
and flush plate
type of S-series
All models of leak-
and C-series of age relay (Mois-
2000A frame and
ture-fungus treat-
lower.
ment of the 2nd
• Moisture-fungus kind only)
treatment of the
2nd kind
All models of S-
and C- series
(Note 2) (Note 2)
• Front connection,
rear connction,
and flush plate All models of S-
and C- series
type of series S
and C of 2000A
frame and smaller
18