What is creepage and clearance distance?
What is creepage and clearance distance?
Clearance is the shortest distance in air between two conductive parts. Creepage distance means the shortest distance along the surface of a solid insulating material between two conductive parts.
How does creepage differ from clearance spacing?
The parameters for pad-to-pad, pad-to-trace, trace-to-trace spacing—basically any spacing rule that is applied between conductive elements over an insulating surface—is creepage, not clearance. Spacing between conductive elements through air is clearance.
What is electrical CTI?
Tracking Index Test. The Comparative Tracking Index (CTI) is the maximum voltage, measured in volts, at which a material withstands 50 drops of contaminated water without tracking. Tracking is defined as the formation of conductive paths due to electrical stress, humidity, and contamination.
How do you calculate creepage distance?
The distance measure of along the surface of the solid insulating material is called creepage distance….What is Creepage and Clearance Distance of Insulator?
| S No. | Degree of Pollution | Recommended Creepage Distance for Insulators |
|---|---|---|
| 1 | Clean areas | 16 mm/kV |
| 2 | Moderately polluted areas | 20 mm/kV |
| 3 | Industrial areas | 22 mm/kV |
| 4 | Heavily polluted areas | 25 mm/kV + |
Why is electrical creepage and clearance important?
Creepage & Clearance distances form part of the product’s electrical insulation system that protects the user from a Risk of Shock. Creepage and Clearance measurements are required between live parts and across electrical insulating materials.
Why do we need creepage distance?
The isolation required between parts with different operating voltages, to prevent against unacceptable risk, is the primary reason for the importance of creepage and clearance distances. It [creepage] is the shortest distance between two conductive parts, measured through air.
What is CTI in PCB?
Comparative Tracking Index (CTI) is the extent to which the insulating material of the PCB can resist the unwanted current to flow between traces on the board. It is a measure of the ability of the PCB substrate to withstand any breakdown between two tracks on the PCB surface.
What is CTI value in PCB?
PCB CTI Value The comparative tracking index value depicts the resistance of the printed circuit board materials against ecological influences like moisture and dirt. This is well explained in terms of when the value is higher, then the higher the material is, the more resistant.
What is clearance and creepage in PCB?
Creepage is the shortest distance between conductor traces on a PCB along the surface of the insulation material while clearance is defined as the minimum distance through the air (line of sight) between two conductor traces. Clearance and creepage distances between two PCB conductors.
What is bushing creepage?
distance. Minimum nominal creepage distance is the shortest distance along the surface of an insulator between two conductive parts. In the case of bushings, this is the distance between the bushing top metallic dome/terminal and the flange, which is referred to in terms of mm/kV, Fig.
What is creepage distance in PCB?
Creepage: This is the distance between two conductors on the surface of the board, or along the surface of insulating material. Clearance: This is the line-of-sight distance between two conductors through the air.
What is clearance clearance clearance and creepage?
1 Clearance: In the “line of sight” distance or the shortest air path between two conductors. The shortest distance that can achieve insulated through the air. 2 Creepage: The shortest distance between two conductors along the insulating surface. 3 Creepage must be greater than or equal to clearance.
What is the minimum and maximum creepage distance of high voltage insulator?
Minimum creepage distance are 16-25 mm/kV. For high pollution area, these value must be increased. Distance between two terminal of the high voltage insulator is called clearance distance. Clearance shall be dimensioned to withstand the required impulse withstand voltage, in accordance to table “Clearances to withstand transient overvoltages”.
What is creepage distance and why is it important?
These usually include one or more sheds; downward facing cup-shaped surfaces that act as umbrellas to ensure that the part of the surface leakage path under the ‘cup’ stays dry in wet weather. The distance measure of along the surface of the solid insulating material is called creepage distance.
What are the IEC tolerances for actual creepage distances?
For actual creepage distances, the specified manufacturing tolerances are applicable (IEC 60273, 60305, 60433 and 60720). rms value corresponding to the highest voltage for equipment (phase to phase).
