Rod Gap Breakdown Voltage Tables

More details on Rod Gap procedures and construction

The following table values valid for:

1.27 cm square rods (1/2")
27 deg C
760 torr (1013 mBar)
15.5 torr water vapor pressure
(11 g/cc water content for impulses).

The voltages in the table reflect the breakdown of the rod gap +/- 8%

Rod Gap Spacing	Voltage	1/5 uSec Pos impulse	1/5 uSec Neg impulse	1/50 uSec Pos impulse	1/50 uSec Neg impulse
cm	kV	kV	kV	kV	kV
2	26
4	47
6	62
8	72
10	81	101	111	90	97
15	102
20	124	179	208	160	178
25	147
30	172	256	301	226	262
40	225	348	392	279	339
50	278	431	475	334	407
60	332	513	557	397	470
70	382
80	435	657	701	511	585
90	488
100	537	820	855	629	703

Humidity Correction

H20 Vapor Pressure (torr)	2.5	5	10	15	20	25	30
Correction Factor %	-16.5	-13.1	-6.5	-0.5	4.4	7.9	10.1

Data taken from tables and graphs in Naidu & Kamaraju, High Voltage Engineering.

Rod Gap Spacing	Voltage	1/5 uSec Pos impulse	1/5 uSec Neg impulse	1/50 uSec Pos impulse	1/50 uSec Neg impulse
cm	kV	kV	kV	kV	kV
2	26
4	47
6	62
8	72
10	81	101	111	90	97
15	102
20	124	179	208	160	178
25	147
30	172	256	301	226	262
40	225	348	392	279	339
50	278	431	475	334	407
60	332	513	557	397	470
70	382
80	435	657	701	511	585
90	488
100	537	820	855	629	703

Rod Gap Spacing	Voltage	1/5 uSec Pos impulse	1/5 uSec Neg impulse	1/50 uSec Pos impulse	1/50 uSec Neg impulse
cm	kV	kV	kV	kV	kV
2	26
4	47
6	62
8	72
10	81	101	111	90	97
15	102
20	124	179	208	160	178
25	147
30	172	256	301	226	262
40	225	348	392	279	339
50	278	431	475	334	407
60	332	513	557	397	470
70	382
80	435	657	701	511	585
90	488
100	537	820	855	629	703

Rod Gap Spacing	Voltage	1/5 uSec Pos impulse	1/5 uSec Neg impulse	1/50 uSec Pos impulse	1/50 uSec Neg impulse
cm	kV	kV	kV	kV	kV
2	26
4	47
6	62
8	72
10	81	101	111	90	97
15	102
20	124	179	208	160	178
25	147
30	172	256	301	226	262
40	225	348	392	279	339
50	278	431	475	334	407
60	332	513	557	397	470
70	382
80	435	657	701	511	585
90	488
100	537	820	855	629	703