Revisamos el detector de humo y el cuadro eléctrico.

Revisamos comes from revisar. In this sentence, it can mean:

• we check / we inspect (present tense)
• we checked / we inspected (simple past, also called the preterite)

So revisamos is one of those Spanish forms that can mean either present or past. You know which one it is from the context.

For example:

• Cada mes revisamos el detector de humo. = Every month we check the smoke detector.
• Ayer revisamos el detector de humo. = Yesterday we checked the smoke detector.

You usually rely on context, especially time words or the surrounding conversation.

Some clues:

• Present: routine, general statements, instructions, habits
  
  • Revisamos el detector cada año.
• Past: completed action, often with words like ayer, anoche, la semana pasada
  
  • Ayer revisamos el detector.

This overlap happens with some -ar verbs in the nosotros form:

• hablamos = we speak / we spoke
• miramos = we look / we looked
• revisamos = we check / we checked

Spanish often uses the definite article more explicitly than English does. Here, el appears before each singular noun because each item is being identified separately:

• el detector de humo
• el cuadro eléctrico

This is very natural in Spanish when listing nouns joined by y.

Compare:

• Revisamos el detector de humo y el cuadro eléctrico.
• English: We checked the smoke detector and the electrical panel.

You would not normally drop the second el here.

Because de humo is a type/classifying phrase, not a reference to specific smoke.

So:

• detector de humo = smoke detector
• literally, detector of smoke

In Spanish, this noun + de + noun structure is very common for naming objects or categories:

• gafas de sol = sunglasses
• cepillo de dientes = toothbrush
• mesa de madera = wooden table

You would say del humo only if you meant of the smoke, referring to some specific smoke already mentioned, which is not the case here.

In Spain, cuadro eléctrico usually means the electrical panel, fuse box, or breaker panel in a building or home.

It is a very common Spain Spanish term. Depending on context in English, you might translate it as:

• electrical panel
• fuse box
• breaker box
• consumer unit (especially in British English)

So this is a good example of vocabulary that is very natural in Spain.

Because in Spanish, most descriptive adjectives usually come after the noun.

So:

• cuadro eléctrico
• puerta principal
• coche rojo

This is the normal word order. Putting the adjective before the noun is sometimes possible in Spanish, but it often changes the tone or meaning. In this case, eléctrico naturally goes after cuadro.

It has an accent because the stress falls on léc:

• e-léc-tri-co

Spanish spelling rules require a written accent here to show the correct stress.

Without the accent, electrico would not follow normal stress patterns correctly. So the accent mark is necessary.

Yes, you could use other verbs, but they are not always exactly the same.

• revisar = to check, inspect, go over
  Very natural for equipment, documents, systems, etc.
• comprobar = to verify, check, make sure
  Often used when confirming whether something works or is correct.
• inspeccionar = to inspect
  More formal or technical.

So:

• Revisamos el detector de humo sounds very natural.
• Comprobamos el detector de humo is also possible, especially if you mean you tested it.
• Inspeccionamos el detector de humo sounds more formal.

Because humo is usually treated as an uncountable noun here, like smoke in English.

So:

• detector de humo = smoke detector

You are not talking about separate individual smokes; you are talking about the substance or type of thing the detector detects.

That is why humo stays singular.

Grammatically, revisar can sometimes mean to review, but in this sentence that would sound unnatural in English.

Because the objects are:

• el detector de humo
• el cuadro eléctrico

the most natural meanings are:

• we checked
• we inspected
• we examined

So even though revisar can mean review in other contexts, here check/inspect is the right idea.

For example:

• Revisamos el informe. = We reviewed the report.
• Revisamos el detector. = We checked the detector.

Yes, it sounds natural and standard in Spain Spanish.

In particular:

• revisamos is a normal verb choice
• detector de humo is standard
• cuadro eléctrico is especially typical in Spain

So this is a good, idiomatic sentence for Peninsular Spanish.