Minimum Electrical Clearance
Minimum Electrical Clearance As Per BS:162.
| INDOOR | ||
| Voltage in KV | Phase to earth in mm | Phase to phase in mm |
| 0.415 | 15.8 | 19.05 |
| 0.600 | 19.05 | 19.05 |
| 3.3 | 50.8 | 50.8 |
| 6.6 | 63.5 | 88.9 |
| 11 | 76.2 | 127.0 |
| 15 | 101.6 | 165.1 |
| 22 | 139.7 | 241.3 |
| 33 | 222.25 | 355.6 |
Minimum Electrical Clearance As Per BS:162.
| OUTDOOR | ||
| Voltage in KV | Phase to earth in mm | Phase to phase in mm |
| 6.6 | 139.7 | 177.8 |
| 11 | 177.8 | 228.6 |
| 22 | 279.4 | 330.2 |
| 33 | 381 | 431.8 |
| 66 | 685.8 | 787.4 |
| 110 | 863.6 | 990.6 |
| 132 | 1066.8 | 1219.2 |
| 220 | 1778 | 2057.4 |
Minimum Working Clearance:
| OUTDOOR SWITCHYARD | ||
| Voltage in KV | To ground in mm | Between section(mm) |
| 11 | 2750 | 2500 |
| 33 | 3700 | 2800 |
| 66 | 4000 | 3000 |
| 132 | 4600 | 3500 |
| 220 | 5500 | 4500 |
Minimum Ground Clearance As Per IE-1956(Rule 77)
| Voltage in KV | To ground in mm |
| 132 | 6.10 |
| 220 | 7.00 |
| 400 | 8.84 |
| 800 | 12.40 |
Minimum Clearance between Lines Crossing Each Other (IE-1957)
| System Voltage | 132KV | 220KV | 400KV | 800KV |
| Low & Medium | 3.05 | 4.58 | 5.49 | 7.94 |
| 11-66KV | 3.05 | 4.58 | 5.49 | 7.94 |
| 132KV | 3.05 | 4.58 | 5.49 | 7.94 |
| 220KV | 4.58 | 4.58 | 5.49 | 7.94 |
| 400KV | 5.49 | 5.49 | 5.49 | 7.94 |
| 800KV | 7.94 | 7.94 | 7.94 | 7.94 |
Minimum Height above Railway As Per IE-1957
| Voltage | Broad Meter & Narrow Gauges |
| Above 66KV up to 132KV | 14.60 Meter |
| Above 132KV up to 220KV | 15.40 Meter |
| Above 220KV up to 400KV | 17.90 Meter |
| Above 400KV up to 500KV | 19.30 Meter |
| Above 500KV up to 800KV | 23.40 Meter |
Various Air clearances to be provided as per IE rule 64
| Voltage KV | 33KV | 66KV | 110KV | 220KV | 400KV |
| BIL (Kvp) | 170 | 325 | 550 | 1050 | 1425 |
| P-E (cm) | 30 | 63 | 115 | 240 | 350 |
| P-P(cm) | 40 | 75 | 135 | 210 | 410 |
| P-G (Meter) | 3.7 | 4.0 | 4.6 | 5.5 | 8.0 |
| Section Clearance(Mt) | 2.8 | 3.0 | 3.5 | 4.3 | 6.5 |
Clearances from Buildings of HT and EHT voltage lines IE Rule 80
| Vertical Distance | |
| High voltage lines up to 33KV | 3.7 Meter |
| Extra High Voltage | 3.7 Meter + Add 0.3 meter for every additional 33KV |
| Horizontal clearance between the conductor and Building | |
| High Voltage Up to 11 KV | 1.2 Meter |
| 11KV To 33KV | 2.0 Meter |
| Extra High Voltage | 2.0 Meter + Add 0.3 meter for every additional 33KV |
Clearance above ground of the lowest conductor As per IE Rule 77
| Over head Line Across Street | |
| Low and Medium Voltage | 5.8 Meter |
| High Voltage | 6.1 Meter |
| Over head Line Along Street (Parallel To Street) | |
| Low and Medium Voltage | 5.5 Meter |
| High Voltage | 5.8 Meter |
| Over head Line Without Across or Along Street | |
| Low/Medium /HT line up to 11KV If Bare Conductor | 4.6 Meter |
| Low/Medium /HT line up to 11KV If Insulated Conductor | 4.0 Meter |
| Above 11 KV Line | 5.2 Meter |
| Above 33KV Line | 5.8 Meter + Add 0.3 meter for every additional 33KV |
Clearance between conductors and Trolley / Tram wires (IE Rule 78)
| Low and Medium Voltage | 1.2 Meter |
| High Voltage Line Up to 11KV | 1.8 Meter |
| High Voltage Line Above to 11KV | 2.5 Meter |
| Extra High Voltage Line | 3.0 Meter |
Clearances from Buildings of low & medium voltage lines(IE Rule 79 )
| For Flat roof, Open Balcony, Verandah Roof and lean to Roof | |
| Line Passes Over Building Vertical Clearance | 2.5 Meter |
| Line Passes Adjustment of Building Horizontal Clearance | 1.2 Meter |
| For pitched Roof | |
| Line Passes Over Building Vertical Clearance | 2.5 Meter |
| Line Passes Adjustment of Building Horizontal Clearance | 1.2 Meter |