[Boatanchors] Storm Damage to Electronics

[rbethman]

As posted earlier:

> Yes, when the neutral is broken, things get wild.  This also occurs when
> the ground is broken.  The poles in areas of VERY good soil conductivity
> can run ground by pole butt grounding.  However, places like coral
> islands with changing tides, REQUIRE a continuous ground from pole to pole.
>
> Otherwise, the same effect is seen when the tide changes.
>
> Been there, done that.  Eniwetok Atoll 1977.  The engineers designed the
> system solely on butt grounds.  Bad news!  We spent one day stringing a
> fourth overhead ground over a 40 acre rock of coral.
>
> The issue went away.  The neutrals were ALWAYS connected.

NOTE: The neutrals WERE ALWAYS CONNECTED!

Distribution lines in residential areas are *ALMOST* always WYE 
systems.  This is done for economy.  in lieu of 4160/2400, they have 
gone to 12470/7200.

The cost of single phase transformers with a primary of 12470 is 
SIGNIFICANTLY higher than those of 7200.

Delta distributions are *ALMOST* exclusively done for commercial areas.  
This is because they DO use three phase power.  Then you have 120/208 
and 240 416 *IF* WYE connection is used on the secondary.

Residential is entirely different.  The neutral carries current all the 
time.

Bob - N0DGN
On 11/5/2011 1:07 PM, J. Forster wrote:
>> What does that make your dryer look like?
> A floating single phase load with a protective ground.
>
>> This argument would infer that 240 or what is essentially 250, is two
>> phase.
>>
>> It certainly is NOT.
> It depends on whether there is a neutral or not.
>
> A typical US house is a flat two-phase. Some loads, like dryers and hot
> water heaters, are single phase 240 VAC loads with a protective ground,
> but no neutral.
>
> It's entirely the same as whether the load is line-to-line (Delta) or
> line-to-neutral (Wye) in a 3 phase system. A 3-phase Delta needs no
> neutral.
>
> -John
>
> I've NEVER seen a neutral used for a dryer connection.  It is the two hots and a *safety* ground!