[AMRadio] #4 wire from mains? - they gotta be kidding


D. Chester k4kyv at charter.net
Wed May 9 23:52:20 EDT 2007


I believe I used #6 or #8  for mine, and even that seems like overkill.  But 
the idea is to maintain the best line voltage regulation possible.  The 
bigger  the wire, the better.  Better to have it and not need it, than to 
need it and not have it.  But at the 1 kw power level (about 3000 watts 
drain off the a.c. mains) there is no need for #4 wire on a 220 volt 
circuit.  A 110 volt circuit would be a different matter.

One thing I found with the way the Gates is wired, is that it violates the 
electrical code.  They ground the a.c. neutral directly to the transmitter 
cabinet.  The neutral should never be strapped to ground anywhere except at 
one point and only one point: the ground rod located at the service entrance 
to the house.  Inside the building past the circuit breaker box, the neutral 
wire should always be insulated and treated exactly the same as a hot wire.

Not only is grounding the neutral dangerous and a violation of the NEC, it 
is an excellent way to create ground loops that result in inexplicable a.c. 
hum in various audio circuits.  I lifted the neutral off the grounded 
cabinet in mine, and ran a separate ground wire from the cabinet to the 
electrical system ground.
The danger in strapping the two together is that if the neutral wire should 
happen to open for any reason, the ground wire would be carrying the full 
neutral line current.  This could result in a.c. voltage on some nominally 
grounded metallic objects.  Of course, the Gates runs off 220 volts, so 
there should NORMALLY be very little if any neutral current.  But I would 
still lift the neutral off the cabinet and ground the cabinet separately 
with a dedicated ground wire.

Don k4kyv 




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