I think you do have to be concerned about it, now that you have realized the
hazard exists. As to what standard requires a breaker, I would say that your
normally-applicable standard has an overarching implied provision that the
product must be 'safe', otherwise it doesn't meet the standard. An
unaddressed shock hazard means that the product is not safe.
 
Alternatively, you could apply IEC/IEEE/UL/EN 00000001:-14.5E9 'Common
sense'.
 
With best wishes DESIGN IT IN! OOO - Own Opinions Only
 <http://www.jmwa.demon.co.uk/> www.jmwa.demon.co.uk J M Woodgate and
Associates Rayleigh England
 
Sylvae in aeternum manent.
 
From: Kunde, Brian [mailto:[email protected]] 
Sent: Friday, November 4, 2016 2:38 PM
To: [email protected]
Subject: [PSES] AC Mains Outlet fuses or daul pole breaker??
 
Greetings Experts.
 
If we send 230Vrms out of a product to power an external device through an
IEC Outlet connector and we need to provide Overcurrent Protection for this
port internal to our device, can I use two fuses or do I have to use a
double pole circuit breaker?
 
Since our product can be used in a 220-230 Vrms power system which cannot
guarantee polarity on the plug (such as Europe) or that the neutral will be
grounded (some North American power systems for example), we have to have
over-current protection on BOTH sides of the line (all current carrying
conductors). 
 
But when we supply power externally to another device, it is possible that
one fuse could open and the other side of the line is HOT to Earth. Someone
working on the external device could put a meter across the line as see
there is no voltage and assume the AC mains is OFF not knowing that one side
of the line it still HOT to Earth. This could cause a hazardous condition.
 
SO, this is the reason for my question. If our device supplies power
externally to another device, can we use fuses which could cause the
hazardous condition I explained above, OR must we use a Double Pole Circuit
Breaker which opens all HOT conductors simultaneously? If I must use a
breaker, what standard or rule dictates this requirement?
 
OR is this even a scenario we have to be concerned about?  Since the
external device has a warning label to disconnect power cord before
servicing, is this even something to be concerned about?
 
BTW, my product is Laboratory Equipment (UL/IEC 61010-1) to sell on a
worldwide market. 
 
Thanks,
The Other Brian
  _____  


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http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used 
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