6
CU R R E NT A N D VOLTAG E I N STRU M E NT TR A N S FOR M E R S
I N S T R U C T I O N S FO R I N S TA L L AT I O N , USE A N D M A I N T EN A N C E
Secondary connections
The terminals, screws, nuts and washers are made
of stainless steel. Secondary grounding screws
and secondary terminal fastening screws are made
of nickel-plated brass.
The secondary terminal cover box used for most
types is made from the plastic and provided with
three detachable threaded inserts. (Instruction
how to provide removing of cable grommet on a
secondary terminal cover – please see appendix 5).
The terminals are provided with M5 screws for sec-
ondary wiring connection and with through going
holes for direct earthing of the secondary circuit
by M5 screws. The terminal cover is sealable.
Degrees of IP protection
Indoor transformers: IP40 or IP30 for transformers
TTR, BB, KOKS
Max. Tightening
torque
(Nm)
Min. Tightening torque
(Nm)
M5
3.5
2.8
M6
4
3
Tab. 2. The maximum permissible tightening torques for secondary
screw connections
Max. diameter of the cable or wire connected to
one terminal of the secondary is: 2x Ø 2.5 mm.
For terminal marking see Appendix 1.
—
07
—
09
—
08
Connection screws
Screw for terminal earthing
Base plate
—
06 KOKS 24 shielding
connection
—
07 Example of current
transformer terminal
box
—
08 Example of voltage
transformer terminal
box
—
09 Cross section of
double line secondary
terminal box
—
06
2 possibilities of HV connection of CT
Aluminium cover
with cutted hole
for busbar
Spring contact
(should be used
on both sides)
Primary busbar
Primary busbar
HV belt
(should be used
on back side)
L-type washers
(have to be used
on all 8 inserts
with M8x16
screws)
