2
SECTION 1 ACB
Introduction
This manual is a guide to normal site installation, operation
and maintenance procedures. ‘M-PACT’ circuit breakers
should only be installed, operated and maintained by
competent and properly authorised personnel.
If further information is required, concerning any aspect of
operation or maintenance of ‘M-PACT’ circuit breakers, please
contact:
GE Power Controls.
Tel: 0151 524 1122
Fax:0151 524 6282
Quality Assurance
All ‘M-PACT’ circuit breakers have been designed and
manufactured to the highest technical standards. Strict
procedures, in compliance with ISO 9001, ensure first class
product quality.
Options Check Sheet
This will be provided with each circuit breaker delivered, listing
all optional features included on both circuit breaker and M-
PRO protection unit. The check sheet will reflect all optional
features
Serial Number
A dedicated serial number will be allocated to each circuit
breaker manufactured. This will be located in two easily
accessible positions:
(a)
On the top face of one of the retractable lifting brackets
(see Fig. 9 page 5).
(b)
On the left side (viewed from front) of the front facia.
The serial number should be quoted in any communication
concerning the circuit breaker.
Storage
Circuit breakers and cassettes should be stored in a clean and
dry place and should be kept in their original packaging. It is
not recommended to store breakers in corrosive environments
above LC1 (sea salt mist) and G1 as per ANSI/ISA-S71.04-
1985.
Ensure that closing springs are discharged and circuit
breakers are in the OFF position while in storage.
Safety Precautions
It is recommended that the following precautions be included
in any procedural instructions to personnel concerned with the
handling, operation or maintenance of ‘M-PACT’ circuit
breakers.
Before detailed inspection or any maintenance work is
commenced:-
• All electrical supplies to the circuit breaker should be switched
off.
• The circuit breaker should be tripped to the OFF position and
the closing springs discharged. This releases stored energy in
the spring mechanisms thus eliminating risk of injury due to
inadvertent tripping or closing during inspection and
maintenance.
While handling the breaker, care should be taken to avoid risk
of injury from moving parts.
• Application of a cable/busbar lockable earthing device
(optional accessory) may be advisable for additional safety
during system maintenance.
The circuit breaker and its accessories must always be used
within their designated ratings.
• Use of the specially designed circuit breaker handling truck
(optional accessory) is recommended when removing the
breaker from its cassette.
Neutral Pole CT
WARNING – When using an earth leg current transformer
(supplied with Standby Earth Fault) the earth leg CT will be
open circuited when the breaker is withdrawn from its cassette.
Under certain circumstances current may still flow in the earth
giving rise to a high induced voltage at the CT secondary
terminals. As a safety precaution it is recommended, under
such conditions, that a carriage switch be fitted in the cassette
(see page 9) to enable short circuiting of the CT secondary
terminals when the circuit breaker is withdrawn.
The circuit breaker and its accessories must always be used
within their designated ratings.
