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Author Voltage drop in home wiring?
Salmon Egg

2006-04-14, 2:21 pm

I am continuing to track down my low voltage problem under load. I would
guess that my wiring is at least 100 feet that I can see easily. I will try
to track it back to the distribution transformer.

When I plug in a 1500W (12.5A if resistive) toaster, my voltage drops by
about 2.5V. What range of values can be expected for series impedance and
transformer regulation for home power?

Bill
-- Ferme le Bush


gfretwell@aol.com

2006-04-14, 3:21 pm

On Fri, 14 Apr 2006 16:17:38 GMT, Salmon Egg <salmonegg@sbcglobal.net>
wrote:

>I am continuing to track down my low voltage problem under load. I would
>guess that my wiring is at least 100 feet that I can see easily. I will try
>to track it back to the distribution transformer.
>
>When I plug in a 1500W (12.5A if resistive) toaster, my voltage drops by
>about 2.5V. What range of values can be expected for series impedance and
>transformer regulation for home power?
>
>Bill
>-- Ferme le Bush
>



That sounds like less voltage drop than I would expect in 100' of #12
copper at 12.5a. My calculator says it should drop 4.825v
SQLit

2006-04-14, 8:21 pm


"Salmon Egg" <salmonegg@sbcglobal.net> wrote in message
news:C0651932.223AB%salmonegg@sbcglobal.net...
> I am continuing to track down my low voltage problem under load. I would
> guess that my wiring is at least 100 feet that I can see easily. I will

try
> to track it back to the distribution transformer.
>
> When I plug in a 1500W (12.5A if resistive) toaster, my voltage drops by
> about 2.5V. What range of values can be expected for series impedance and
> transformer regulation for home power?
>
> Bill
> -- Ferme le Bush



I remember 5% drop to the farthest load. 3% at a service.


daestrom

2006-04-15, 2:21 pm


"Salmon Egg" <salmonegg@sbcglobal.net> wrote in message
news:C0651932.223AB%salmonegg@sbcglobal.net...
>I am continuing to track down my low voltage problem under load. I would
> guess that my wiring is at least 100 feet that I can see easily. I will
> try
> to track it back to the distribution transformer.
>
> When I plug in a 1500W (12.5A if resistive) toaster, my voltage drops by
> about 2.5V. What range of values can be expected for series impedance and
> transformer regulation for home power?
>


Don't have exact numbers for you, but the bolted short-circuit current from
a typical pole pig can be several thousand amps. So if we assume 4000 amps,
then the transformer and feeder impedance would be 240V/4000A = 0.06 ohm.

daestrom

Salmon Egg

2006-04-15, 6:21 pm

On 4/15/06 9:54 AM, in article Ty90g.1285$kz3.1234@twister.nyroc.rr.com,
"daestrom" <daestrom@NO_SPAM_HEREtwcny.rr.com> wrote:

>
> "Salmon Egg" <salmonegg@sbcglobal.net> wrote in message
> news:C0651932.223AB%salmonegg@sbcglobal.net...
>
> Don't have exact numbers for you, but the bolted short-circuit current from
> a typical pole pig can be several thousand amps. So if we assume 4000 amps,
> then the transformer and feeder impedance would be 240V/4000A = 0.06 ohm.
>
> daestrom
>

The problem has been solved!

I was zeroing in on the problem. Indications were a bad neutral somewhere. I
hired an electrician to trace the problem. With all my book learning, I
figured out that hands on experience was more important than anything else.

It turned out that the neutral connection in the panel box was loose. The
electrican tracked that down, stripped off some insulation and ran the
neutral through two logs instead of one.

Bill
-- Ferme le Bush


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