In UL standard 1446, Electrical Insulation System (EIS)is defined as: “an intimate combination of insulating materials used in electrical equipment. For example, the combination of a coil form, separators, magnetwire coating, varnish, leadwire insulators, and outer wrapping of relay coil”
EIS (Electrical Insulation System) Testing
Qualification of an insulation system to either UL 1446 or IEC standard requires testing of complete, assembled insulation systems. Electrical equipment manufactures are faced therefore with testing the actual equipment substituting a motorette or transformerette that represent their system; or using a recognized EIS through a material supplier, Because final recognition of a system by UL requires that the system go through 5000 hr of heat aging at the lowest of the three or four temperatures the system is tested at, many manufacturers choose the preapproved system option.
The EIS test is composed of two test procedures, One qualifies the major components of the insulating system by constructing the Test Rigs (Motorette) for testing .The major components include ground insulation, magnet wire, intertwining insulation, and varnishes, The dip varnish can be considered a minor component if the motorette or transformerette did not use a varnish. The other procedure is called the “sealedtube testing” which is for the minor components of the insulating system such as the tapes, lead wires, sleeving material and the dip varnishes.
The Allowable Magnet Wire Substitutions
Use the following for MW substitutions into established EIS
If this type / class is in the EIS 
You can use these types / class without additional testing. Substitutions are LIMITED to same Chemical Group only. 
All of the magnet wires in this Chemical Group are solderable Polyurethane (PU & PU/PA) 

MW 75 /130 (PU) 
MW 28,MW 79,MW 80,MW 82,MW 83 
MW 28*/130 (PU/PA) 
MW 75,MW 79,MW 80,MW 82,MW 83 
MW 79 /155 (PU) 
MW 80,MW 82,MW 83 
MW 80*/155 (PU/PA) 
MW 79,MW 82,MW 83 
MW 82 /180 (PU) 
MW 83 
MW 83*/180 (PU/PA) 
MW 82 
All of the magnet wires in this Chemical Group are solderable Polyesters (SP) 

MW 26 /155 (SP) 
MW 27,MW 77,MW 78 
MW 27*/155 (SP/PA) 
MW 26,MW 77,MW 78 
MW 77 /180 (SP) 
MW 78 
MW 78*/180 (SP/PA) 
MW 77 
All magnet wires in this Chemical Group are nonsolderable Polyesters (P, P/PA, modified P or PEI or PEAI or PAI) 

MW 5 /155 (P) 
MW 24,MW 30,MW 76, MW 35,MW 73,MW 74,MW 81,MW37C,MW35A 
MW 24*/155 (P/PA) 
MW 5,MW 30,MW 76,MW 35,MW 73,MW 74,MW 81,MW37C,MW35A 
MW 30 /180 (P) 
MW 76,MW 35,MW 73,MW 74,MW 81,MW37C,MW35A 
MW 76*/180 (P/PA) 
MW 30,MW 35,MW 73,MW 74,MW 81,MW37C,MW35A 
MW 35C /200 (P/PAI)
= MW 36C 
MW 73,MW 74,MW 81,MW37C,MW35A 
MW 73/200 (P/PAI) 
MW 35,MW 74,MW81,MW37C,MW35A 
MW 74/200 (PEAI) 
MW 35,MW 73,MW 74,MW 81,MW37C,MW35A 
MW 81/220 (PAI) 
MW37C,MW35A 
MW37C/220(P/PAI) 
MW81,MW35A 
MW 35A/220(P/PAI) = MW 36A 
MW 81,MW 37C 
All magnet wires in this Chemical Group are nonsolderable Polyimide (PI) 

MW 16 /240 = MW 20/240 
No substitutions, no equivalent type 
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