!

Valid values

heating temperature

Name of equipment, live part

The highest permissible heating temperature, ° С

1. Current-carrying (except for contacts and contact connections) and non-current-carrying and metal parts, not insulated and not in contact with insulating materials.

120 ° C

H

In the meantime, there is no need to know about it. ”

180 ° C

3. Contacts made of copper and copper alloys.

Y

In the meantime, there is no need to know about it. ”

90 ° C

A

In the meantime, there is no need to know about it. ”

100 ° C

E

In the meantime, there is no need to know about it. ”

120 ° C

B

In the meantime, there is no need to know about it. ”

130 ° C

F

In the meantime, there is no need to know about it. ”

155 ° C

2. Isolated or touching
with insulating materials, heat resistance classes according to GOST 8865:

Without coatings:

in air / in insulating oil / in SF6 gas

75/80/90 ° C

With overlaid silver plates:

in air / in insulating oil / in SF6 gas

120/90/120 ° C

Silver or Nickel Plated:

in air / in insulating oil / in SF6 gas

105/90/105 ° C

Silver coated at least 24 microns:

in the air

120 ° C

Tin plated:

in air / in insulating oil / in SF6 gas

90/90/90 ° C

4. Contacts cermet tungsten
and molybdenum / in insulating oil:
copper based / silver based.

85/90 ° C

5. Outputs of devices made of copper, aluminum and their alloys, intended for connection with external conductors of electric fields:

Without cover

90 ° C

Tin, silver or nickel plated

105 ° C

6. Bolted contact connections made of copper, aluminum
and their alloys:

Without cover
in air / in insulating oil / in SF6 gas

90/100/105 ° C

Tin plated
in air / in insulating oil / in SF6 gas

105/100/105 ° C

Tin plated
in air / in insulating oil / in SF6 gas

105/100/105 ° C

7. AC fuses for voltage
3 kV and above:

Compounds of copper, aluminum or their alloys in air, unplated / tin plated:

Detachable (pressing with bolts or screws) / including fuse leads

In the meantime, there is no need to know about it. ”

90/105 ° C

With a detachable contact connection carried out by springs

In the meantime, there is no need to know about it. ”

75/95 ° C

Metal parts used as springs:

phosphor bronze
and similar alloys

In the meantime, there is no need to know about it. ”

105 ° C

Copper

In the meantime, there is no need to know about it. ”

75 ° C

8. Insulating oil in the upper layer of switching devices.

90 ° C

9. Current transformers built into oil circuit breakers, transformers, reactors:

Windings

-

Magnetic cores

-

10. Contact connections of voltage control devices of power transformers under load (OLTC) when operating in air in oil:

Of copper, its alloys and copper-containing compositions without silver coating.

-

With pressing bolts or other elements that ensure the rigidity of the connection.

-

Spring loaded and self-cleaning
in the process of switching.

-

Spring loaded and non-self-cleaning
in the process of switching.

-

11. Current-carrying conductors of power cables in continuous / emergency mode:

With insulation:

Vulcanizing
polyethylene.

90/130 ° C

Polyvinyl chloride compound
and polyethylene.

70/80 ° C

Rubber elevated

heat resistance.

90 / - ° C

Rubber.

65 / - ° C

With impregnated paper insulation with viscous / depleted impregnation and rated voltage, kV:

6kV

65 / - ° C

1kV

80 ° C

3kV

80 ° C

35kV

50 / - ° С

10kV

60 / - ° С

20kV

55 / - ° C

12. Collectors and slip rings, unprotected and protected when insulated with heat resistance classes GOST 8850:

A / E / B

-

F / H

-

13. Plain / rolling bearings

80/100 ° C

Note: these tables apply if no other standards have been established for specific types of equipment.