VEGA Capacitive electrodes EL … - Manual (Page 32)

32 Capacitive electrodes EL …
Capacitive electrode with external overvoltage protection unit
Vessel without cathodic corrosion protection
E2
E1
A2
A1 A1
A2 E2
E1 1
2 Typ
B62-36G
Typ
B62-36G
B A
Ex-area Not-Ex-area (control
room)
either overvoltage arrester
either overvoltage arrester
B62 - 36 G Ex 0 (metal housing) or
B62 - 36 G Ex (plastic housing)
(L
i
= 0,15 mH, C
i
= 1,5 nF)
Electrode EL
Outer
isolation Outer
isolation
Screen
Screen
Signal conditioning
instrument or
safety barrier
Earth / PA-terminal
to potential
equalisation line
External earth terminal
Note:
[A] Between control room and overvoltage protection system a suitable cable, if required with screen or metal
cover, should be used. Screen or metal cover - if required - must be only connected to the overvoltage
protection system on the electrode side.
[B] Between overvoltage protection system and capacitive electrode a suitable cable with metal cover, screen or
a suitable cable with metal protection tube must be used (screen, metal cover or protective tube must be
connected to the potential equalization).
Test voltage of cable A and B: ≥ 500 V AC
min. 4 mm 2 Cu
Vessel
Zone 0
Electrical connection