[TowerTalk] guy posts math

[Roger (K8RI) on TT]

Most of the residential areas around here (Midland MI) have only power 
and cable on them.  Telco lines are buried in the right-of-way. 
Transformers are likely 12 KVA, 2 homes per transformer although the one 
out front has two home plus my shop. I'm fairly certain my neighbor has 
a 200A service as well.  He also has a garage/shop that is fed from his 
main panel.

I do know that with 4 4500W heaters on continuous, we burned one to a 
crisp.  I think duty cycle for a residence is around 25% or about 50A.  
Originally our house and the neighbor had only 60A service,

I'll have to look for the pole plate.

73

Roger (K8RI)

On 7/21/2015 9:29 AM, Jim Thomson wrote:
> Date: Mon, 20 Jul 2015 02:32:54 -0500
> From: "W5GN" <w5gn at mxg.com>
> To: "'Jim Thomson'" <jim.thom at telus.net>, <towertalk at contesting.com>
> Subject: Re: [TowerTalk] guy posts math
>
> My dad ran Bartlett Tree who serviced all of the AEP lines in
> SW Virginia and their engineer said they put 7 feet of a 35 foot
> pole in the ground in the late 50s. Sounds like your TELCO poles
> had lighter loads and thus put less in the ground than power poles.
>
> 73
>
> Barry, W5GN
>
> ##  IF only telco + cable are on the pole, the poles are usually shorter..like 35 feet.
> IF it’s a joint use pole..and also has commercial AC power  with the usual 12.5 kv  or
> 14.4 kv HV on top, with lower voltage 240/120 down below plus telco and cable etc,
> then the poles are typ 40 ft tall.   The HV sits another 18 inches above the 40 ft pole...
> via an insulator on top of steel.   What diam are ur poles ?   What kind of wood ?
> Joint use pole applications  typ makes up 95% of pole applications.   You rarely see
> telco +  cable co only poles, but they do exist.
>
> ## They all have a metal plate on em..exactly 12  foot up from the bottom.  The plate
> if u know how to read it, will have info on it which also gives the exact co-ordinates
> of the pole location.   When u see that the plate is  6 ft above the grnd, u know the
> pole  is exactly 6 ft into the ground.   If the plate was 5 ft above grnd, the pole is 7 ft
> into the grnd.   This is the case for a 40 ft pole.
>
> ##  Those 50 kva /75 /kva /100 kva /125 kva xfmrs weigh one helluva lot....and if u have
> ever seen em on the grnd, they are a lot bigger than u think.   The most I have seen on one pole
> is  3 x 100 kva xfmrs.      The place u see guy wires, typ at two levels  is where stuff Ts  off to one side,
> placing  a huge side load on the pole.  or where a pole line does a right angle.   Typ guy strand is either
> .3125  or .375 inch for the bottom level.....and   either  .375  or .4375  for the top level.
>
> ##  If u ever see a new pole or poles laying on the ground in  residential neighbourhoods etc, get out
> and measure the distance  between the plate and the bottom end.   Then compare that to the total
> end to end length of the pole.   30 ft poles will have the plate  10 ft from the end.  40 ft poles will
> have the plate 12 ft from the end etc.
>
> ##  concrete pole have gone out of vogue.   They had a lot of re-bars in them, running the length of the
> pole. I don’t know how deep they put concrete poles into the grnd.  Only saw em used for joint use
> applications.
>
> Jim   VE7RF
>
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-- 

73

Roger (K8RI)


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