Accessories

Function

Cardew C is used if the insulation monitoring device is connected to the secondary connection of an MV/LV transformer (according to the rules and conventions that apply in the various countries).

It protects the low-voltage (LV) installation against over voltage hazards. It is connected to the secondary connection of the transformer. Cardew C can be used on the following systems:

• U < 1000 V AC

• U < 300 V DC

Selection table

Un: Nominal Phase-to-Phase Voltage of AC System

Ui: Arcing Voltage

Type of Cardew C

Accessible neutral

Not accessible neutral

U ≤ 380 V

U ≤ 220 V

400 V < Ui ≤ 750 V

250 V

380 V < U ≤ 660 V

220 V < U ≤ 380 V

700 V < Ui ≤ 1,100 V

440 V

660 V < U ≤ 1,000 V

380 V < U ≤ 660 V

1,100 V < Ui ≤ 1,600 V

660 V

1,000 V < U ≤ 1,560 V

660 V < U ≤ 1,000 V

1,600 V < Ui ≤ 2,400 V

1,000 V

Dimensions

Mounting

• Cardew C mounted directly on busbars

• Mounting with plate-mounted base

Connection

Function

ZX limiting impedance enables you to create an installation with a high-impedance grounded neutral system (1500 Ω at 50 Hz).

ZX limiting impedance can be used on the following systems:

• Umax = 480 V AC

• Umax = 345 V DC

Dimensions

Mounting

Connection

Function

Dimensions

Mounting

Connection

(1) Voltage adaptor connected to a phase

(2) Voltage adaptor connected to neutral