Det kommer an på om veggfestets plassering ved grunnmuren er riktig.

It means it depends on.

This is a fixed expression built from å komme an på = to depend on.
So:

• Det kommer an på været. = It depends on the weather.
• Det kommer an på om ... = It depends on whether ...

You should learn kommer an på as one unit of meaning, not word by word.

Because å komme an på is a multi-word verb expression, and in a main clause the finite verb moves to the second position.

The full infinitive is:

• å komme an på

But in a normal statement, Norwegian puts the finite verb early:

• Det kommer an på ...

So this split is normal. Compare:

• Det kommer an på tiden.
• Hva kommer det an på?

This is similar to separable verb-like patterns in other Germanic languages.

Here det works like the English it in it depends on ....

It does not refer to a concrete object. It is a kind of formal or dummy subject that fills the subject position because Norwegian clauses normally need a subject.

So:

• Det kommer an på ... = It depends on ...

Here om means whether.

So:

• om veggfestets plassering ... er riktig = whether the wall mount’s placement ... is correct

Be careful: om can mean different things in different contexts, for example:

• om = whether
• om = about
• om = in / after in some time expressions

In this sentence, it clearly means whether.

Veggfestets is the genitive form of veggfeste.

Breakdown:

• veggfeste = wall mount / wall attachment / wall fixing
• veggfestet = the wall mount (definite singular)
• veggfestets = the wall mount’s

So:

• veggfestets plassering = the wall mount’s placement / the placement of the wall mount

This -s genitive works much like English 's.

Both are possible, but they sound slightly different in style.

• veggfestets plassering = the wall mount’s placement
• plasseringen av veggfestet = the placement of the wall mount

The first is a genitive construction. The second uses av = of.

Norwegian often uses both patterns, and one may sound more natural depending on style and context. In technical writing, compact noun phrases like veggfestets plassering are very common.

Plassering means placement, positioning, or sometimes location/position depending on context.

It comes from the verb å plassere = to place.

So:

• plassering = the act or result of placing something

In this sentence, veggfestets plassering refers to where the wall mount is placed.

Ved grunnmuren means something like by the foundation wall, near the foundation, or at the foundation wall.

Breakdown:

• ved = by / near / at
• grunnmuren = the foundation wall / the foundation

The exact English translation depends on the building context. Ved often indicates physical proximity rather than direct contact.

Grunnmuren is the definite form of grunnmur.

• grunnmur = foundation wall / foundation
• grunnmuren = the foundation wall / the foundation

The ending -en is a common definite singular ending for masculine nouns in Bokmål.

So:

• ved grunnmuren = by the foundation wall

Because that whole phrase is the subject of the om-clause.

Structure of the subordinate clause:

• om
  • subject
    • verb
      • complement

So here:

• om = whether
• veggfestets plassering ved grunnmuren = subject
• er = is
• riktig = correct

In other words, the clause means:

• whether [the wall mount’s placement by the foundation wall] is correct

Yes.

The main clause is:

• Det kommer an på ...

Inside the subordinate clause introduced by om, Norwegian does not use the main-clause verb-second rule in the same way. The subject normally comes before the verb.

So this is normal:

• om veggfestets plassering ... er riktig

If there were an adverb, you would see the subordinate-clause pattern more clearly:

• Det kommer an på om veggfestets plassering ved grunnmuren faktisk er riktig.

Notice how faktisk comes before er in the subordinate clause.

Here riktig means correct, right, or proper.

So:

• er riktig = is correct

In this context, it probably means that the placement is technically correct or appropriate.

Sometimes, but not always with exactly the same feel.

Both riktig and rett can mean right/correct, but riktig is often the more neutral choice in technical or evaluative contexts like this one.

So:

• er riktig sounds very natural here.
• er rett may sound less natural depending on context.

For a sentence about correct placement or proper positioning, riktig is a safe and common choice.

Yes. Norwegian uses compound nouns very often.

• vegg = wall
• feste = fastening / mount / attachment

Together:

• veggfeste = wall mount / wall attachment

Likewise, grunnmur is also a compound:

• grunn = ground / base
• mur = wall

Learning to recognize compounds is very helpful in Norwegian, especially in technical language.

A simple way to break it down is:

• Det kommer an på = It depends on
• om = whether
• veggfestets plassering ved grunnmuren = the wall mount’s placement by the foundation wall
• er riktig = is correct

So the full structure is:

• It depends on whether [the wall mount’s placement by the foundation wall] is correct.

This is a very common Norwegian pattern:

• Det kommer an på om ... = It depends on whether ...