Bartosz wrote:

So, what is wrong/illegal with it and what should be done to make it legal/safe?

If your application uses safety class II methode, means the use of protection earth is avoided, by introducing double or enhanced isolation, then between output and input side of MOC3021 an isolation path length of at least 8mm is necessary. But this is NOT guaranteed if you take this chip in standard through hole package (Case 730A-04). Here, according pins are 7.62mm distanced from another. Including about 1mm of solder pad at each pin, only about 5.6mm isolation path exists. And this IS illegal!

MOC3021 is also fabricated in 'Case 730D-05', which does fullfill the standards. But the chip might not be available in this strange looking package at your local store, very probably...

Bartosz also wrote:

I don't really care if it's legal or not...

Sorry, but that really sounds stupid! If someone is killed, because you violated a well known and law become standard you will be put into prison!

I'm really tired to read such overweening statements. If you want to be treated seriously, then comply to the standards. Very competent people introduced them as reaction to the occurence of thousands over thousands of terrible accidents with many many hurted and killed people!

Kai