{"id":3352,"date":"2026-08-04T17:00:00","date_gmt":"2026-08-04T17:00:00","guid":{"rendered":"https:\/\/chac-electric.com\/?p=3352"},"modified":"2026-10-14T06:50:39","modified_gmt":"2026-10-14T06:50:39","slug":"seleccion-de-interruptor-automatico-unipolar-vs-bipolar","status":"publish","type":"post","link":"https:\/\/chac-electric.com\/es\/blog\/single-pole-vs-double-pole-mcb-selection\/","title":{"rendered":"\u00bfCu\u00e1ndo deben los armadores de paneles utilizar un interruptor autom\u00e1tico miniatura (MCB) monopolar o bipolar?"},"content":{"rendered":"

Single-pole and double-pole MCB selection begins with the conductors that the circuit must switch and protect. A familiar pole label is not enough: a single-phase circuit may be line-to-neutral or line-to-line, and a two-pole product may have a different protected-Disposici\u00f3n de los postes<\/a> from another two-pole product.<\/p>\n

\"\u00bfCu\u00e1ndo<\/p>\n

A practical way to frame the pole decision<\/h2>\n

Draw the complete circuit first, including the source, neutral, protective conductor, shared neutrals and the intended isolation point. Then record whether each pole is switched, protected, or both. The MCB selection range<\/a><\/strong> can be reviewed after those inputs are fixed, not before.<\/p>\n

Which conductors must the device disconnect?<\/h2>\n

A single-pole MCB may suit a line conductor where the applicable installation rules permit that arrangement. A double-pole device may be required where line and neutral must open together, but the selected model must document how the neutral pole is treated. Shared or borrowed neutrals are a common reason to stop and redraw the circuit.<\/p>\n

What does a single-pole MCB actually cover?<\/h2>\n

One pole does not automatically describe the entire circuit\u2019s isolation or fault behaviour. Verify the rated voltage, breaking capacity<\/a>, protected pole and the installation rule for the circuit topology. A nominally single-phase supply is not always a line-to-neutral supply.<\/p>\n

\"autom\u00e1tico\"<\/p>\n

Why should 1P+N be reviewed separately from 2P?<\/h2>\n

1P+N commonly indicates line-and-neutral switching with overcurrent protection on the line pole, while a 2P device can have another protection arrangement. Treat the labels as a prompt to inspect the wiring diagram and markings, not as interchangeable product names.<\/p>\n

When does a double-pole MCB become the better review route?<\/h2>\n

Consider it when simultaneous disconnection is required by the design or local rules, when the supply arrangement makes both conductors part of the isolation boundary, or when the selected product\u2019s documented ratings match that duty. Pole count does not by itself increase breaking capacity.<\/p>\n

How should the comparison appear on the panel schedule?<\/h2>\n

List the circuit topology, pole configuration, protected poles, AC or DC duty, rated voltage, breaking capacity, trip curve and neutral arrangement as separate fields. This makes supplier responses comparable and exposes missing information before the bill of materials is released.<\/p>\n

Which product pages can support the shortlist?<\/h2>\n

For a model-level check, review the interruptor autom\u00e1tico en miniatura CQB2-63<\/a><\/strong> page and compare its published configuration with the panel drawing. Related MCB options<\/a> should be treated as separate model reviews.<\/p>\n

When is pole count not enough for final selection?<\/h2>\n

Stop the comparison and return to the responsible designer when the project needs discrimination, local-code interpretation, a DC application, shared neutrals or model-specific approval. IEC 60898-1<\/a> y IEC 60947-2<\/a> have different scopes, so the applicable standard must be identified rather than assumed.<\/p>\n

For a double-pole MCB selection<\/strong>, the final schedule should show the actual line and neutral arrangement, protected-pole designation and the evidence used to approve the device.<\/p>\n

That record is also useful when a later service change introduces a shared neutral or a different supply topology. The installer can see which assumptions were part of the original approval instead of treating the pole label as a universal rule.<\/p>\n

It also gives the panel reviewer a clear way to reject a nominally similar device when its terminal marking, neutral treatment or permitted voltage does not match the approved circuit.<\/p>\n

Preguntas frecuentes<\/h2>\n

\u00bfCu\u00e1l es la diferencia b\u00e1sica entre un MCB 1P y un 2P?<\/h3>\n

Un MCB de 1P tiene un polo para el conductor asignado. Un MCB de 2P tiene dos polos vinculados mec\u00e1nicamente que se abren juntos. La documentaci\u00f3n del producto seleccionado a\u00fan debe confirmar la funci\u00f3n y la disposici\u00f3n de protecci\u00f3n de cada polo.<\/p>\n

\u00bfEs 1P+N lo mismo que 2P?<\/h3>\n

No. Una etiqueta 1P+N se asocia com\u00fanmente con la conmutaci\u00f3n de fase y neutro con protecci\u00f3n contra sobrecorriente en el polo de fase, mientras que un dispositivo 2P puede tener una disposici\u00f3n de polos protegidos diferente. Confirme tanto el diagrama de cableado como las marcas del producto antes de tratarlos como alternativas.<\/p>\n

\u00bfUna etiqueta 2P demuestra que ambos polos est\u00e1n protegidos?<\/h3>\n

No. El recuento de polos por s\u00ed solo no establece c\u00f3mo se protege cada polo. Solicite la hoja de datos y la informaci\u00f3n de cableado del modelo seleccionado, luego comp\u00e1relos con el requisito del circuito.<\/p>\n

\u00bfSe puede utilizar un interruptor autom\u00e1tico magnetot\u00e9rmico (MCB) de CA en un circuito de CC?<\/h3>\n

Solo cuando el dispositivo exacto est\u00e9 expl\u00edcitamente clasificado y documentado para el servicio de CC previsto. La norma IEC 60898-2 aborda requisitos adicionales para interruptores autom\u00e1ticos de CA\/CC unipolares y bipolares elegibles, pero no hace que todos los interruptores autom\u00e1ticos en miniatura (MCB) de CA sean adecuados para CC.<\/p>\n

\u00bfQu\u00e9 normas debe revisar un constructor de tableros para una solicitud de interruptor autom\u00e1tico en miniatura (MCB)?<\/h3>\n

Empiece por la norma y la regla de instalaci\u00f3n nombradas en los documentos del proyecto. IEC 60898-1 cubre los interruptores autom\u00e1ticos de CA para uso dom\u00e9stico e instalaciones similares dentro de su \u00e1mbito, mientras que IEC 60947-2 es un contexto de norma de interruptores autom\u00e1ticos de baja tensi\u00f3n para personas instruidas o cualificadas. El requisito del proyecto y los documentos del modelo seleccionado determinan la base final.<\/p>\n

\u00bfQu\u00e9 debe incluirse en una solicitud de cotizaci\u00f3n (RFQ) para un MCB?<\/h3>\n

Incluya el diagrama unifilar, la disposici\u00f3n de la alimentaci\u00f3n y de los circuitos, los conductores que se van a conectar, la expectativa de polos protegidos, la corriente de CA o CC, la norma aplicable, la evidencia requerida del modelo seleccionado, las restricciones del panel y cualquier solicitud de marca o embalaje.<\/p>\n

\u00bfCu\u00e1ndo no es suficiente esta gu\u00eda para la selecci\u00f3n final?<\/h3>\n

No es suficiente cuando el proyecto requiere coordinaci\u00f3n final, interpretaci\u00f3n de c\u00f3digos locales, orientaci\u00f3n sobre trabajo en vivo o una aprobaci\u00f3n espec\u00edfica del modelo. Esas decisiones requieren la informaci\u00f3n real del circuito y de la carga, las normas locales y la documentaci\u00f3n del producto seleccionado.<\/p>\n

Referencias<\/h2>\n