"to throw a monkey wrench in the works"/ " don't throw a spanner in the works"

[Anne Frank]

Hi natives! In American English you have the idiom "to throw a monkey wrench in the works", British people say " don't throw a spanner in the works", I have a question: do you use these two for only work-related situations, or the daily ones too?
For example, may I say: she really loves your son, don't throw a spanner in the works.

 

[sdgraham]

Don't let "works" confuse you into thinking it applies to work-related situation.

works:

• Mechanical Engineering the working parts of a machine:the works of a watch.

 

[Anne Frank]

Don't let "works" confuse you into thinking it applies to work-related situation.

works:

• Mechanical Engineering the working parts of a machine:the works of a watch.

So I may use it as in my previous example?

 

[owlman5]

Yes, Anne, you may do that. You can use the phrase in talk about personal matters and relationships.

 

[Anne Frank]

Yes, Anne, you may do that. You can use the phrase in talk about personal matters and relationships.

Oh, thanks a lot.

 

[Uncle Jack]

The same applies in BrE. "Throw a spanner in the works" can be used for any situation where something or someone prevents something from happening, or creates difficulty.

However, your original expression "Don't throw a spanner in the works" is not particularly idiomatic. I am not saying that you cannot use it, but the usual use is to describe something that has happened or the probable effect of something, rather than as an imperative.