16 September 2012

Safety Clearance for Electrical Panel:



 Working Space around Indoor Panel/Circuit Board (NES 312.2):

Voltage
Exposed live parts to Not live parts( or grounded parts )Exposed live parts to Grounded parts (concrete, brick, and walls).Exposed live parts on both sides
Up to 150 V
0.914 Meter (3 Ft)
0.914 Meter (3 Ft)
0.914 Meter (3 Ft)
150 V to 600 V
0.914 Meter (3 Ft)
1.07 Meter (3’6”)
1.22 Meter (4 Ft)

 Clearance around an Indoor electrical panel (NES 110.26):

Description of Clearance
Distance  (min)
Left to Right the minimum clearance
0.9 Meter (3 Ft)
Distance between Panel and wall
1.0 Meter
Distance between Panel and Ceiling
0.9 Meter
Clear Height in front of Panel>480V
2.0 Meter
Clear Height  in front of Panel <480v span="span">
0.9 Meter (3 Ft)
Clearance When Facing Other Electrical Panels < 480V
0.9 Meter (3 Ft)
The width of the workingspace in front of the Panel
The width of Panel or 0.762 Meter which is Greater.
Headroom of working spaces for panel boards (Up to 200Amp)
Up to 2 Meter
Headroom of working spaces for panel boards (More than 200Amp &Panel height is max 2 Meter)
Up to 2 Meter( If Panel height is max 2 Meter)
Headroom of working spaces for panel boards (More than 200Amp &Panel height is more than 2 Meter)
If Panel height is more than 2 Meter than clearance should not less than panel Height
Entrance For Panel (More than 1200 Amp and over 1.8 m Wide)
One entrance required for working space (Not less than 610 mm wide and 2.0 m high )
Personal Door For Panel (More than 1200 Amp)
Personnel door(s) intended for entrance to and egress from the working space less than 7.6 m from the nearest edge of the working space
Dedicated Electrical Space.
Required Space is width and depth of the Panel and extending from the floor to a height of 1.8 m (6 ft) above the equipment or to the structural ceiling, whichever is lower
The door(s) shall open in the direction of egress and be equipped with panic bars, pressure plates, or other devices that are normally latched but open under simple pressure

the work space shall permit at least a 90 degree opening of equipment doors or hinged panels

 Clearance for Conductor Entering in Panel (NES 408.5):

Description of Clearance
Distance  (min)
Spacing between The conduit
or raceways(including their end fittings) and Bottom of Enclosure
Not rise more than 75 mm (3 in) above the bottom of the enclosure
Spacing Between Bottom
of Enclosure and Insulated bus bars, their supports,
200 mm
Spacing Between Bottom of Enclosure and Non insulated bus bars
200 mm

 Clearance between Bare Metal Bus bar in Panel (NES 408.5):

Voltage
Opposite PolarityMounted on Same
Surface
Opposite PolarityWhere Held Free in AirLive Parts to Ground
Up to 125 V19.1 mm12.7 mm12.7 mm
125 V to 250 V31.8 mm19.1 mm12.7 mm
250 V to 600 V50.8 mm25.4 mm25.4 mm

 Clearance of Outdoor electrical panel to Fence/Wall (NES 110.31):

Voltage
Distance  (min)
600 V to 13.8 KV
3.05 Meter
13.8 K V to 230  KV
4.57 Meter
Above 230 KV
5.49 Meter

 Working Space around Indoor Panel/Circuit Board (NES 110.34):

Voltage
Exposed live parts to Not live parts( or grounded parts )Exposed live parts to Grounded parts (concrete, brick, and walls).Exposed live parts on both sides
601 V to 2.5 K V
0.914 Meter (3 Ft)
1.2 Meter (4 Ft)
1.5 Meter (5 Ft)
2.5 K V to 9.0 K V
1.2 Meter (4 Ft)
1.5 Meter (5 Ft)
1.8 Meter (6 Ft)
9.0 K V to 25 K V
1.5 Meter (5 Ft)
1.8 Meter (6 Ft)
2.5 Meter (8 Ft)
25 K V to 75 K V
1.8 Meter (6 Ft)
2.5 Meter (8 Ft)
3.0 Meter (10 Ft)
Above 75 KV
2.5 Meter (8 Ft)
3.0 Meter (10 Ft)
3.7 Meter (12 Ft)

 Clearance around an Outdoor electrical panel (NES 110.31):

Description of Clearance
Distance  (min)
Clear work space: Not less than 2.0 Meter high(Measured vertically from the floor or platform) or not less than 914 mm (3 ft) wide (Measured parallel to the equipment).
Entrance For Panel (More than 1200 Amp and over 1.8 m Wide)One entrance required for working space (Not less than 610 mm wide and 2.0 m high )
Entrance For Panel: On Large panels exceeding 1.8 Meter in widthOne Entrance at each end of the equipment.
Nonmetallic or Metal-enclosed Panel in general public and the bottom of the enclosure is less than 2.5 m (8 ft) above the floor or grade levelEnclosure door or hinged cover shall be kept locked.

 Elevation of Unguarded Live Parts above Working Space (NES 110.34E):

Voltage
Elevation  (min)
600 V to 7.5 KV
2.8 Meter
7.5 K V to 35  KV
2.9 Meter
Above 35 KV
2.9 Meter + 9.5 mm/KV

 Working Space for Panel (Code Georgia Power Company):

Voltage
Exposed live parts to Not live parts( or grounded parts )Exposed live parts to Grounded parts (concrete, brick, and walls).Exposed live parts on both sides
Up to 150 V
3.0 Meter
3.0 Meter3.0 Meter
150 V to 600 V
3.0 Meter3.5 Meter4.0 Meter
600 V to 2.5 KV
3.0 Meter4.0 Meter5.0 Meter
2.5 KV to 9 KV
3.0 Meter5.0 Meter6.0 Meter
9 KV to 25 KV
5.0 Meter6.0 Meter6.0 Meter

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