How is it possible to get a masters in electrical engineering in one year?
How is it possible to get a masters in 1 year? Simple, sign up for a course which offers a masters degree in 1 year. Perhaps not so simple.

In the UK, we have something called an integrated masters degree offered on many engineering courses. This typically follows a 3 year bachelors degree. The theory being that if you have just spent the last 3 years studying the same subject, you can then simply continue on using that as the foundation to build on to get a masters.

The reason a masters degree, which is not integrated, is usually (again from a UK perspective) 2 years, is that the first year is intended as almost a foundation year to get everyone up to speed with the more specialised skills that they may be missing. For example if you do a BSc in physics, you could then do an MSc in EE, but you wouldn't have the same electronics knowledge that somebody who was coming off a BEng in EE would have. In fact at the Uni I went to, during our third (final) bachelors year, we would frequently share modules with those doing the first year of their MSc for this very reason.

Now it may be possible if you have the relevant skills (e.g. if you have a good bachelors degree in the same subject) to be able to skip a year of a 2 year masters degree, and just do the final year. However this would be very much dependent on finding a Uni which would allow that, and probably also would require some form of aptitude test to ensure that you have the skills to do so. I doubt this would be a common offering though.

Again, this is a very UK centric answer. I'm not familiar with other countries systems. As far as I know, in the US, bachelors degrees are typically more like 4 years because the US education system ends high school at a level more equivalent to the GCSE (or possibly AS) level from a UK perspective. So the first year of Uni in the US is more like an A-level equivalent in the UK.