Video 05 · 0:32
Every breaker passed the test: does that mean they are all the same?
During maintenance at a 115 kV substation the breakers met the contact-resistance criterion and the overall verdict was good. Even so, four showed pole-to-pole spread well above the rest: on one it reached 75.72 %.
- Duration
- 32 seconds
- Language
- Spoken in Mexican Spanish
- Captions
- Spanish captions, switchable from the player
- Published
- Published September 18, 2026
What is behind this video
Contact resistance is measured pole by pole, injecting direct current through the closed contact and reading the voltage drop. The usual acceptance criterion is a maximum value — on this switchgear, below 100 micro-ohms — and that is what decides whether a breaker passes.
A pass-or-fail criterion leaves part of the information out. The three poles of a breaker share the same mechanism and the same operation count: if one measures three times another, something is wearing them unevenly, even if all three stay under the limit. That difference between poles — the spread — fails nobody, but it anticipates.
At the 115 kV substation of a paper and board mill, six vacuum breakers on the 13.8 kV switchgear met the limit. Pole-to-pole spread, however, ran from 4.33 % on one feeder to 75.72 % on another, with two intermediate cases at 22.28 % and 18.52 %. The feeder with the highest figure measured 32.0, 27.3 and 13.6 micro-ohms across its poles: within criterion and, at the same time, the first candidate for focused maintenance.
The figure does not change this year's verdict; it changes the order of the next window. Compared against the previous measurement, it is also the earliest signal that a mechanism is behaving differently.
The presenter in these videos is a character generated with artificial intelligence: the image and the voice do not belong to TEVKO personnel. The technical content and the figures quoted come from documented work and from the pages linked on each page.
Transcript — English translation
Every breaker passed the test. Does that mean they are all the same?
The test was contact resistance, pole by pole. All of them met the criterion, but on four of them the difference between poles was well above the rest, and that can indicate uneven wear. That figure helps decide which breaker gets attention first.
If you have results from previous tests, send them to the email shown on screen.
Transcript — original Spanish audio
Todos los interruptores pasaron la prueba. ¿Entonces están igual?
La prueba fue de resistencia de contactos, polo por polo. Todos cumplieron, pero en cuatro la diferencia entre polos quedó muy por encima del resto, y eso puede indicar desgaste desigual. Ese dato ayuda a decidir qué interruptor se atiende primero.
Si tienes resultados de pruebas anteriores, compártelos al correo que aparece en pantalla.
The same Spanish captions ship as a WebVTT track inside the player. The contact shown on screen at the end of the video is ventas@tevko.com.
Questions this video answers
If a breaker meets the contact-resistance criterion, is it in good shape?
It complies, which is not the same thing. The video puts it this way: all of them met the criterion, but on four the difference between poles was well above the rest. In the published case that accompanies the piece the overall verdict was good, and that spread is still what told the breakers apart.
What does a high pole-to-pole spread indicate?
It can indicate uneven contact wear. The video frames it that way: it is a figure that helps decide which breaker to address first in the next maintenance window.
Related pages
Technical content reviewed by TEVKO Technical Management · last reviewed: September 17, 2026
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