Converting Transformer Classifications Old to New

[dnem]

The problem is that Im getting conflicting info
This site says
http://www.hammondpowersolutions.com/faq/what-is-meant-by-class-in-insulation/
old class A is new class 105
old class B is new class 150 or 130
old class F is new class 180
old class H is new class 220

This site says
http://www.electricalengineeringtoolbox.com/2014/08/nema-insulation-classes-for-transformers.html
old class A is new class 105
old class B is new class 130
old class F is new class 155
old class H is new class 180
old class R is new class 220

Who is correct.?

 

[dnem]

In addition, I'm referencing this ATP book that refers to "class 150" repeatedly. And Im seeing "class 155" spoken about in the NEC 450.21(B)X1+X2. Does this NEC reference prove that all references to class 150 are wrong.? Why would somebody makeup a class 150.?

I wish I could access the NEMA website. They apparently want money just to see the simplest thing. I dont see how I can access the answer to even a basic question without paying them for a subscription.

 

[Smart $]

http://www.schneider-electric.us/en/faqs/FA101887/

Class A 105°C
Class B 150°C
Class F 180°C
Class R 200°C
Class H 220°C

I'd take info on Schneider's site over the two you referenced any day.

 

[dnem]

Schneider / Square D is a pretty reliable source but so is NFPA. Since NEC 450.21(B)X1+X2 states that there is a class 155, are both sources right.? Is there both a class 150 and a class 155.?

 

[Smart $]

Schneider / Square D is a pretty reliable source but so is NFPA. Since NEC 450.21(B)X1+X2 states that there is a class 155, are both sources right.? Is there both a class 150 and a class 155.?

I don't believe there is a "standard" 155. I believe the 155 value was chosen so it would be higher than 150, but much closer to 150 than 180 just in case some manufacturer published a non-standard in-between rating.