[Amps] SAFETY WITH HIGH VOLTAGE

[Roger Parsons]

I am also quite suspicious of a wire-wound resistor
failing to a low value. 

FWIW, my work includes certification of equipment as
Intrinsically Safe for use in underground gaseous
mines. This equipment has to remain safe with any two
unrelated faults. All certification bodies of which I
am aware will accept that a wire-wound resistor can
only fail open or high resistance - most other types
are considered to be capable of failure to a short. I
would really hate there to be a documented failure of
a wire-wound resistor to a low value, and for this to
be noticed by the certification authorities, even
though intrinsically safe equipment is always
operating at dramatically lower voltages and currents
than most amplifiers discussed on this reflector!

If this happened my work would become very much
harder, and huge amounts of equipment already
operating in potentially explosive atmospheres would
actually present an ignition hazard.

73 Roger
VE3ZI





	
	
		
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