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Protection Relays & Controls

NGR SERIES – CANADA

Simplified Circuit Diagram with Littelfuse Neutral-Grounding-Resistor Monitor

NGR

L2

CT

L1

ER Series

Sensing Resistor

NGR Monitor

Note 2

Note 1

Transformer or

Generator Neutral (XO)

Note 4

Note 5

Note 3

Note 6

NGR SYSTEM

Note 1: Use minimum #8 AWG white or grey conductor insulated to system voltage to connect NGR to neutral.

Note 2: Use conductor insulated to system voltage (#14 AWG is typically used) and a separate lug at the X0 point

to connect ER Series Sensing Resistor to neutral.

Note 3: Locate NGR system near transformer or generator.

Note 4: Two-conductor twisted cable required, shielded recommended.

Note 5: Voltage between ER Series Sensing Resistor terminals R and G is limited to 100 V by internal clamp.

Note 6: Use minimum #8 AWG green or bare conductor to connect NGR to ground.