* An 'electrician' is usually someone who works inside homes or other buildings -- for example, laying or checking wiring, or checking washing machines, refrigerators etc. The more formal term for this is 'electrical engineer' -- but see below. You'd never use 'electrical worker' for this sort of person.
* 'electrical worker' sounds more to me like a poorly-skilled or unskilled person in the electricity industry, probably working outdoors -- for example, laying cables in the ground.
* 'electrical engineer' suggests a skilled person who has probably undergone training in electronics and has certificates etc to prove it, who works either indoors or outdoors.

If it's in the US, they may use different terms.