Conform to  EN 60598-1 clause 9.2

Where connection is made by a plug or a similar device, then this shall be regarded as part of the complete luminaire and shall be included in the tests and similarly for any separate controlgear.
For tests of 9.2.3 to 9.2.11, a fixed luminaire intended for mounting with its body in contact with a surface shall be tested with an expanded metal spacer interposed between the luminaire and the mounting surface. The spacer shall be at least equal in overall size to the projection of the luminaire, and have dimensions as follows:

Longway of mesh 10 mm to 20 mm
Shortway of mesh 4 mm to 7 mm
Strand width 1.5 mm to 2 mm
Strand thickness 0.3 mm to 0.5 mm
Overall thickness 1.8 mm to 3 mm