Why indeed? As a native english speaker (AE), I would never say 'an electrical grill'.
Things that are powered by electricity are 'electric'. Things that 'have to do with' or 'are associated with' electricity are electrical.
I have an electric heater.
An electrician is coming to work on the electical components of my (electric) heater.
Can a native Italian speaker answer this question; why, in Google Translate, does this sentence translate as it is here, "Ho una griglia eletricca.", but "My grill is electric." translates as "La mia griglia è elettrico."?
Why does "electric" have two different endings? It is an adjective in both sentences.
You don't need a native Italian speaker for this. Just do not trust any machine translation. Obviously Google does not reflect noun gender for adjectives used alone as
predicates. It seems to reflect the gender in past simple tense, but the sad reality is it just reflects the "gender" of era (and the "gender" of è).
- I have an electric grill. = Ho una griglia elettrica.
- My grill is an electric grill. = La mia griglia è una griglia elettrica.
- My grill is electric. = La mia griglia è
- My grill was electric. = La mia griglia era
- I have an electric fridge. = Ho un frigo elettrico.
- My fridge is an electric fridge. = Il mio frigo è un frigo elettrico.
- My fridge is electric. = Il mio frigo è
- My fridge was electric. = Il mio frigo era
While all of the following indefinite article forms have the same meaning, English and Italian have different rules for choosing which one to use.
a- before any consonant sound
an- before any vowel sound
- uno - before s+consonant, z, x, gn, ps, pn, y, i+vowel for masculine nouns
- un - before all other letters for masculine nouns
- una - before consonants for feminine nouns
- un' - before vowels for feminine nouns