I'm trying to find some safety standards in small dc motors that can be used at home, but I'm failing to see a reliable source that mentions it. Any help or idea on where can I find it?
Safety regarding what? Shock hazard? torque hazard? Fire hazard??
We do not need more rules telling us what we can't do because some stupid was able to hurt themselves doing it.
You DO need to understand what you have and the forces, speeds, and temperatures that it can produce. For motors, it is important to understand that a motor should be secured before starting it so that it does not roll away and get into trouble when it starts. For rotating objects it is sort of vital to have them installed so that they will not come loose and roll around causing damage. For things that get hot it is important to understand how hot they will get and be sure that they are not able to start fires. These are the obvious ones, there are lots more, but I hope that you get the concept.
You ALONE are responsible for behaving safely, just as I alone am responsible for my safety. Nobody needs to be telling me to wear the safety harness when I climb the radio tower, I need to understand that falling 50 feet would hurt, and so I do wear that safety harness and so I do also attach the safety lanyard at each step, so if I do fall it will only be 3 feet. Painful but not fatal.
Motors, just about all small frame DC motors have a locked rotor current. About all you can really do is fuse the motor. As to for example OSHA? Motors driving a belt for example must have a protective shroud so no moving parts are exposed. That being an example of a safety standard. OSHA standard 29 CFR 1910.219, and whether or not rotating round shafts must be guarded. Just as a simple example so it really depends on the motor and applications. There are also safety standards in cases for example if power is lost you do not want the motor to restart on its own when power returns. Then there is the matter of E Stops (Emergency Stop switches strategically placed and again depending on the motor and application. To know what standards may or may not apply you really need a well defined application
So you are concerned with the safety of personnel rather than the equipment I assume?
Anything below 60v is usually considered no risk.
If galvanic isolation is used, there is generally no requirement to Earth ground the system.
There is also NFPA79 as well as NFPA70 (NEC) but this usually is aimed at industrial installations of higher voltage.
Correct fusing and circuit protection should still be used.
Max.