I'm not that sure about that. Far from wanting to leave the EU, Germany is actually trying to take the lead and pull the cart out of the mud, regardless of whether we think their methods and ideas are up to the task or not.
Technical standards are an entirely different matter. While we have the various harmonisition documents, about every country has so many national addendums that the actual regulations vary considerably. I see this all the time with Germans trying to give advice to Austrian DIYers (or even prfessionals in fields they aren't familiar with) and vice versa. For example, in a German TT supply with RCD-protected circuits the earth resistance is only limited by the prospective fault current, that's around 1600 Ohms for a 30 mA RCD. In Austria, there's an absolute limit of 100(!) Ohms, less than 1/10. A German setup would instantly fail testing for that reason (unless earth resistance happened to be low enough anyway). The Brits and Irish extended zone 2 in bathrooms (surrounding baths and showers) from 60 cm to 2 m, the Belgians added a zone 3 (essentially to the same effect), etc. etc.
