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[TowerTalk] shack wiring

To: <>
Subject: [TowerTalk] shack wiring
From: "Jim Thomson" <>
Date: Fri, 30 Jul 2010 02:04:39 -0700
List-post: <">>
Date: Thu, 29 Jul 2010 11:09:46 -0700
From: "Jim Brown" <>
Subject: Re: [TowerTalk] surge protectors

Another suggestion. run 20A circuits (#12) for anything that may get a lot 
of electronic stuff plugged in, with a dedicated neutral for each circuit. 
For long runs, pull in #10. If you do the math, you quickly realize that 
20A will run a LOT of ham gear, everything but big power amps. That big 
13.8V power supply is only dragging about 700W out of the wall to provide 
40A continuous DC, enough to have two rigs keydown in RTTY at the same 
time. AND you can greatly reduce those peak power requirements by using 
smaller power supplies to float deep dischrage batteries. 

### If I remember correctly, in our BC electrical code,  IF  you opt for 
a 20A  circuit  [120 vac]   and use 12 ga  Cu , and also a single 20A breaker,
the 120 vac outlet must be of the 20A  rated variety !   The 20A  rated
120 vac outlets don't resemble the normal 15A  variety.   They use a 
weird  20A  120 vac outlet... which requires the mating  plug.  I think
one blade was straight.. and the 2nd one had a right angle to it, such that
normal  appliances,etc,  could not be plugged into it.   IF a regular  120 vac
outlet is used, and V drop is a concern,  sure, you can use 12 ga wire... but
you must use a 15A  breaker.   10 ga CU  won't fit most  120 vac outlets anyway.
[ they will take 12 ga max] 

##  IF you want to save on wire,  I see no reason why you can't  run 240 vac 
+ neutral  to a duplex 120 outlet... then break the tab off... and then they 
share a 
common neutral.   This is done all the time in kitchens.  Then you can suck 15A 
outlet.   The neutral current is the difference between the two loads. 

## depending on how far the shack is from the main 200A panel.... I decided in 
case, to go to plan B... and simply install a 100A  sub panel on the other side 
of the 
shack wall [ unfinished part of the basement, where the 200A main panel is 
across the
basement from the 100 A  sub panel].   Sub panel was cheap... and is wired back 
to main
panel with 3 ga CU.   Then it's real short lengths [ like <10']  of 120/240 
wiring  from
100A sub panel to shack on other side of wall.   Then I'm not gobbling up 
breaker positions in the main 200A panel either.  

##  each amp gets it own real short dedicated 240 vac circuit  [10 ga]. Also 
loads of 120 vac
circuits.[12 ga]    It's  actually an excellent way to go.  Instead of really 
long multiple runs back to the
200A main panel  [ with huge ga wire, so no V drops] ,  I end up with really 
short multiple 
runs to sub panel.... and zero V drops.   It makes for a cleaner install, and 
WAY less clutter/mess. 
Dunno what the smallest size sub panel you can get these days.  Even a  40-60A 
sub panel,
fed with 8-6 ga cu    would be a winner... and still provide loads of power. In 
the winter time,
after dinner / late at night, I use a 1 kw electric heater in my tiny 8' x 10'  
shack.  Makes more
economical sense  vs  running a gas furnace, and heating up the entire 2000 sq 
ft house. 
During the day time, we will use the gas furnace.  At night, we use the gas 
fireplace upstairs
in living room... and the 1 kw  space heater  for my radio room.  I have  a 5 
kw heater in the 
workshop next door, which takes no time at all to bring my real small work shop 
up to temp....
I only use the 5 kw heater at night. 

##  that was another reason to just install one  sub panel..and be done with 
it.  The 5 kw
heater in the shop next door is  6'  away from the sub panel.    The 1 kw 
heater in the shack
is 12'  away from sub panel.   Feeding real short multiple runs through one 
wall, is a LOT easier
than  drilling out umpteen  ceiling joists. 

later.... Jim   VE7RF  

For a serious multi-two setup, I'd do two 20A circuits and two 240V 
circuits.  One 240V circuit is plenty for SO2R, but you want the second 
circuit if two amps will be in TX at the same time. One 120V circuit will 
run all the transceivers and support stuff for multi-two -- the second 
circuit is a spare, or for non-electronic stuff. Years ago, N6RO was wired 
with six 120V circuits and six 240V circuits, and it's plenty for his 5-
transmitter multi-multi setup. His shack is in his barn (attached to the 
house), and he installed a local panel in the shack. This makes the wiring 
to his outlets much shorter, improving voltage regulation. Naturally, you 
also want big feeders to that panel. 

73, Jim K9YC


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