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Grounding Grid Design: DECREMENT FACTOR
FAULT DUR 0.5S X R 30 to FAULT DUR 1.0S X R 40
IEEE 80 grounding grid design parameters including touch/step voltage safety limits (50 and 70 kg body weight), decrement factors by X/R ratio, and typical soil resistivity values by soil type.
| parameter type | condition | decrement factor (dimensionless) | limiting value | unit |
|---|---|---|---|---|
| DECREMENT FACTOR | FAULT DUR 0.5S X R 30 | 1.0766 | 1.0766 | dimensionless |
| DECREMENT FACTOR | FAULT DUR 0.5S X R 40 | 1.101 | 1.101 | dimensionless |
| DECREMENT FACTOR | FAULT DUR 0.75S X R 10 | 1.0175 | 1.0175 | dimensionless |
| DECREMENT FACTOR | FAULT DUR 0.75S X R 20 | 1.0348 | 1.0348 | dimensionless |
| DECREMENT FACTOR | FAULT DUR 0.75S X R 30 | 1.0517 | 1.0517 | dimensionless |
| DECREMENT FACTOR | FAULT DUR 0.75S X R 40 | 1.0684 | 1.0684 | dimensionless |
| DECREMENT FACTOR | FAULT DUR 1.0S X R 10 | 1.0132 | 1.0132 | dimensionless |
| DECREMENT FACTOR | FAULT DUR 1.0S X R 20 | 1.0262 | 1.0262 | dimensionless |
| DECREMENT FACTOR | FAULT DUR 1.0S X R 30 | 1.039 | 1.039 | dimensionless |
| DECREMENT FACTOR | FAULT DUR 1.0S X R 40 | 1.0517 | 1.0517 | dimensionless |
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