Hi Ron:
IEC 950 Amendment 4 is a stand-alone document, fully integrated
with IEC 950.
Yes, it is "separate" from IEC 950, because IEC 950 only exists
as IEC 950, with no amendments.
Here's the deal the way I understand it:
IEC 950, Second Edition ........................... 1991
Amendment 1 ............................. February, 1992
Amendment 2 ................................. June, 1993
Amendment 3 (integrated with IEC 950) .... January, 1995
Amendment 4 (integrated with IEC 950) .. September, 1996
The reason Amendemnts 3 and 4 are integrated with the standard is
Amendments 3 and 4 change virtually every page in the standard
plus add new pages to cover additional material. Amendments 3
and 4 have vertical lines in the margins to indicate the changed
material.
Our rep to IEC TC 74 also says that Amendment 4 either is, or will
shortly be "incorporated" into EN 60950. As to availability, I
suggest you contact CENELEC directly.
By the way, UL 1950 Third Edition is a close approximation of IEC
950/Amendment 4. The UL folks had access to most of the Amendment
4 proposals, and incorporated them into UL 1950. See the table on
page 17.
Best regards,
Rich
