Insert Availability
22
22-55
24
24-61
ALTITUDE
VOLTAGE RATINGS
D.C.
WORKING
VOLTAGE
A.C.
WORKING
VOLTAGE
R.M.S.
PROOF
VOLTAGE
D.C. OR A.C.
PEAK
Rating 1
Sea level
700
500
2100
300 mb at
20°C
8,500m
550
(27,800 ft)
390
1100
44 mb at
20°C
20,000m
330
(66,000 ft)
230
660
Rating 2
Sea level
120
300 mb at
0
20°C
8,500m
650
(27,800 ft)
44 mb at
20"C
20,000m
(66,000 ft)
380
850
3000
460
1300
270
760
ALTITUDE-THOUSANDS OF FEET (METRES)
Relationship between flashover voltage and
altitude for each voltage rating
VOLTAGE RATINGS
Two categories of voltage rating are specified in
BS9522 F0017, F0038 and N0001.
Rating 1 (700V d.c. working at sea-level) Applicable to the
high contact density inserts shown in the upper section of the
insert availability diagram above.
Rating 2 (1200V d.c. working at sea-level) Applicable to
the inserts shown in the lower section of the insert
availability diagram.
Altitude derating. Information on voltage derating for
operation at altitudes above sea-level can be obtained from
the flashover voltage altitude curves on the left.
7