[TowerTalk] Shack wiring

[K8RI on Tower Talk]

> I'm hoping that history has added the subject of shack wiring, both RF and 
> AC, to the range for Towertalk -- if others disagree, I apologize.
>
> My entire shack is on a single 110V circuit (separate 220 for the 
> amplifier).  Recently I have begun to get low voltage warnings (104.5 
> volts) from my UPS in the morning, and so have put a digital voltmeter on 
> the circuit.  With no load except for the computers (2), the UPS and the

I take it you are reading before the UPS and that only the computers are on 
the UPS?

> table light, voltage right now is 108.7.  My two radios (on receive) cause 
> the voltage to drop about .4 volts.  When the voltage is running low, I

What is it in other locations and other circuits particularly at the 
breaker?  How about the mains coming into the house?

If this is the only circuit that is low, I'd make haste to check out the 
wiring in that circuit.
It could be the breaker itself, the connections to the breaker box, outlet 
connections (usually the circuits are daisy chained from one outlet to the 
next) and splice boxes in the ceiling, or crawl space. (wires also come to 
common points in a circuit where they are tired togeter using wire nuts). 
Wires do come loose in the splice boxes and in the daisy chain at outlets 
creating high resistance joints that give excessive drop and create heat. 
(a real fire hazard)


> typically see 104.7 or 104.8 without the radios, so adding them to the 
> load sets off the UPS.
>
You should be seeing about 115 unless you are at the end of a very long 
line.  Here the voltage is almost always between 115 and 118.

> Two questions, I guess -- is the voltage drop with loading I describe 
> above roughly what you'd expect?  If necessary I can dig out the standby 
> power

I don't see any drop when turning on the radios.  There is some when loading 
the circuit heavily.

> requirements for the two radios.  And second, what is the US spec for line 
> voltage?  The power company is coming out to investigate and I'd like to 
> know where I stand.

The lowest spec used to be 107, but that was with 110 as nominal. I don't 
know what it is now, but I'd think 107 may be less than the minimum.  If 
it's out of spec it means they have to file a report in addition to fixing 
the problem if it's on their end.  They will probably check to the weather 
head or in some cases the feed into the main breaker.  Now days I think they 
like to see it 115 at the panel.

Roger Halstead (K8RI, EN73 & ARRL Life Member)
N833R, World's Oldest Debonair (S# CD-2)
www.rogerhalstead.com
>
> 73, Pete N4ZR
> The World HF Contest Station Database
> was updated 12 January 2005
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