[TowerTalk] Fwd: shack wiring

N1MM tfwagner at snet.net
Wed Aug 4 14:37:54 PDT 2010


When I replaced my 100 amp service entrance with 200 amp in the late 
80's, I wired the downlead on the side of the house to current code.  
That was 0000 aluminum.  I called the power company to schedule moving 
the drop from the street and they had me fill out a usage survey of what 
electrical loads there would be after the switch.  I was adding 1000 
square feet to the house, but the only real additional load I listed on 
the survey was lighting.  I wasn't adding electric heating, cooling or 
other big users of electricity.  The electric utility made the 
determination that the existing #2 copper drop was sufficient, and did 
not replace it.

Note that the current carrying capacity of wires is greater in open air 
than in enclosed spaces, and that explains part of the difference in 
size. The other is that the risk from the drop buring up is far less 
that the risk of the downlead melting.  I guess the drop serves as a 
fuse for the unfused downlead, and that is the other part of the 
rationale for keeping it smaller.  Not to mention that smaller wires are 
cheaper.

73,
Tom - N1MM

On 8/4/2010 2:30 PM, Rick Karlquist wrote:
> You think you have it bad, I have two 100A services
> and one 200A service all running through the same
> set of AWG 4 wires (that's right FOUR gauge).
> The wires are several hundred feet long.  The power
> company guy didn't seem to understand why I had a
> problem with that.
>
> Rick N6RK
>
> Don Tucker wrote:
>    
>> Just what should the wire size be from the pole xmfr to the house and into
>> the 200A panel?
>>
>> Don W7WLL
>>
>> ## ha ha.   I had the power co guy's out here a few months back..and asked
>> them
>> the same thing.  Their answer was... "go ahead and burn it right off the
>> pole" .
>> Here in NA, we are being sold a bill of goods.   Everyone has '200 A'
>> service...
>> but the drop wire into each home is just 1-0  stranded AL.... which then
>> gets
>> spliced into 3-000 stranded CU. .. then into the meter base  [which is the
>> most
>> mickey mouse, piss poor design you ever saw, regardless of who makes em]
>> ..
>> then into main 200A panel.. which imo, they all use undersize buss bars.
>>
>>
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