Using poly on painted cabinet

[philip sabwa]

Hey Guys, I have been a silent follower and only recently opened an account. I have a question but it's directed at DIY pro or generally any person experienced in polyurethane finishes. I recently repainted my tool cabinets and I had some poly left from another project that never got used again. I don't want it to overstay and probably expire so can i use this poly on top of the paint on the cabinets? The cabinet's wood is solid mahogany. 

[Tpt life]

Two suggestions and then the truism that guides them. 
 

1) Read the manufacturers suggestions. 
 

2) Test in an area that is likely to not be seen. 
 

I suggest this path because “paint” and “poly” are not specific enough to make a certain recommendation. What you are asking about Can be done, but is not always a thing the Should be done. 
 

e.g. Oil over latex is never wise. Never put a hard film finish over a flexible one. That could and often does lead to cracks. 

[wtnhighlander]

@Tpt lifeis exactly correct. If the paint is a hard-curing type, like an oil-based enamel, or a mineral acrylic, then top coating with polyurathane is a fairly common practice. Beware that oil-based poly will impart an amber tone.