Specifications

NAIROBI OPERATIONAL HUB
UNOPS Building, UN Lane, Off UN Avenue Tel: [phone]
P.O Box 783,Village Market, 00621 E-mail: [e-mail]
Nairobi, Kenya Website: www.unops.org
UNOPS is ISO 9001 certified
rating to the secondary side and the counter or the meter shall be
calibrated to read the primary Kwh passing through the current
transformers.
L. The current transformers shall be of the ring or slide on busbar type.
M. Three current transformers of 2000/5A shall be provided for each meter.
N. All meters shall be handed over to the concerned local authorities for
Calibration before final erection and connection.
2.07 FUSE SWITCHES
A. Fuse switches shall fully comply with BS 5419 : 1977, IEC 408 : 1972
meeting all of the concerned local authorities requirements.
2.08 MOULDED CASE CIRCUIT BREAKERS
A. The moulded case circuit breakers shall comply with IEC 947-1 and IEC
947-2 standards and shall be of the quick make and quick break type
having free toggle mechanism ensuring full contact pressure until time of
opening, whether actuated automatically or manually. They shall be of
utilization category ‘A’ having rated service breaking capacity (Ics) as
indicated in the drawings. The circuit breakers shall be suitable for
isolation as per IEC 947-2 and shall have rated operation voltage of 500V
50 Hz, insulation voltage of 750 V, 50 Hz. The breaker shall be available
in 3 or 4 pole version as per the drawing. All poles shall operate
simultaneously for circuit breaker opening, closing and tripping. The
mechanism shall be completely enclosed in the compact moulded bakelite
case. The moulded case circuit breaker shall provide class II insulation
(according to IEC 664) between the front and internal power circuits. The
breaker shall be designed for both vertical and horizontal mounting and it
shall be possible to supply power either from the upstream or downstream
side without any adverse effects on the electrical performance. Evidence
of the service breaking capacity (Ics) shall be produced by test certificates
from one of the internationally recognized High Voltage Laboratories
(ASTA, CESI, ESEF/ASEFA, KEMA, PEHLA or SATS).
B. Breakers contacts shall be made of non-welding and non-corrodible
composition. Circuit breakers shall be actuated by a toggle or handle that