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 mtr
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