How to Connect NGR with transformer

[vipineng]

How to Connect NGR with transformer?.Please explain with the process..

 

[collies99]

Two dominant make of NGR fault protection systems in Alberta are I-gard and Littlefuse-Startco. Their web sites are full of technical information. You may have to register.

The NGRs can be supplied from both of these companies but PowerOhm also makes power resistors for NGR uses.

Neutral conductor between the transformer and NGR to have system insulation rating and warning signs are required on the NGR to notify personnel that it may rise to Phase-to-ground voltage level under fault conditions. In Canada Neutral conductor must meet minimum #8 AWG as per CEC requirements. Grounding conductors as required (I never have thought, but I would say minimum #8 AWG also ?).

 

[prc]

How to connect NGR? As the name indicates, it is a resistor( with short time current rating) connected between LV winding neutral to ground to limit LG fault current on secondary side. Some times a protection is provided to resistor for detecting open circuiting of the resistor circuit.

 

[unclebob]

Just make sure you don't have phase-neutral loads (ex: lighting). Removing the neutral may remove the lighting...

 

[LionelHutz]

Just make sure you don't have phase-neutral loads (ex: lighting). Removing the neutral may remove the lighting...

You can still have phase to neutral loads with a NGR.

 

[Mbrooke]

Assuming the NGR is rated for the direct secondary voltage, its inserted between the XO terminal and the grounding/earthing system. The installation voltage and code being used (NEC, NESC) will determine how the NRG is applied along with how the system is treated (under the NEC a 600 volt and under system does not permit L-N loads).

 

[MatthewDB]

You can still have phase to neutral loads with a NGR.

Under IEC rules it is permissible if the neutral is broken by switches and circuit breakers.

Under US / Canadian rules, no phase to neutral loads are permissible. Typically there will be isolation transformers for lighting loads in facilities with an NGR.

 

[LionelHutz]

unclebob's comment made it sound like you can't have a neutral wire when you use a NGR, which simply isn't the case. I wasn't commenting about it being allowed by code or not since there are no details on location or voltage.