Hello,
I have been reviewing the definition of SELV in IEC 950 lately and
have a question that some of you may have answers to.
As I understand it, SELV is defined as voltages less than or equal
to 42.4 Volts Peak or 60 Volts DC. If I convert 42.4 Vp to RMS I get 30
Vrms.
My question is this: is it just a coincidence or is there a rational as
to why the 60 Vdc limit is twice the 30 Vrms limit (which is approx. 1.414
times the 42.4 Vp limit)?
Another way to ask the question is: how did the 60 Vdc SELV
limit get set at 60 Vdc? (The scientific answer is preferred, but political
answers could be interesting...)
Thank you in advance for your input.
Kaan L. Gregersen
Compliance Engineering Manager
Harman Music Group
801-586-7615
