Whether ROHS test must test the 6 kinds of harmful substances or not?
 

The six kinds of harmful substances including four kinds of heavy metals and two kinds of bromine flame retardant organic compounds. When testing, the sample needs to divide into the smallest physical unit (Single material), If the material is ceramic, glass, metal which are non combustible, the text just need to analysis the content of four kinds of heavy metals. If the split material is plastic (due to power, housing, transformers, etc., which generally will add flame retardant), so that usually need to do all six tests.
  
In brief, the general rule is that six tests are test for materials that are flammable, and four tests are test for non combustible materials.                         

  --CE certification body