John, The section of the Wikipedia entry that you have quoted is wrong. No great surprise there.
Fair enough - as you say, no great surprise!
What you don't seem to understand is that the values of voltage that are considered to be sufficiently low to be considered non-hazardous will be different for different applications ...
As I have said repeatedly, I fully understand and accept that bit, but ...
yet all (provided they are below certain values) are considered to be ELV.
This is where I'm getting both confused and surprised. I can fully understand "the voltage considered to be safe in application X" varying between applications (different Xs) but, if this is what you are saying, I can't understand a specific term like "Extra Low Voltage" being defined as having different meanings (values) according to the application.
Is that what you are saying, or are you perhaps saying that there will be different definitions for safe voltages for different applications (which is fine) and/but they will all be called ELV
if they are also within the range of a common (say the IEC) definition of ELV?
Remember that this all started because you questioned my statement that 90V DC was (per IEC definition) ELV.
Here's an extract from IEC/TS 61201, which you might find helpful:
Thanks. The final bit seems to perpetuate my uncertainties:
Voltages below critical levels that are unlikely to be hazardous in this respect have normally been called Extra-Low Voltage (ELV). Based on this information Technical Committees may wish to review their defined values of Extra-Low Voltage.
This does, indeed, seem imply that different Technical Committees might produce their own, different, definitions of "ELV" (rather than just a safe range of voltages in relation to their area of interest) - which is the concept which rather concerns me. Is that your interpretation of what it means?
Kind Regards, John