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Tony Hwang Tony Hwang is offline
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Default Floating neutral or wiring problem?

stan wrote:
On Mar 12, 12:53 am, "scorpster" wrote:
Mystery solved! Southern CA Edison sent over a repair expert tonight within
a couple hours. Turns out that one of the hot legs was broken at the
telephone pole. The neighbor's tree branches are completely tangled around
the wires, putting tension on the wires and causing the entire pole to tilt
at an angle. This unraveled one of the hot wires. He repaired the
connection, and he's sending a crew out within a week to trim the neighbor's
trees, and then replace all the wires between the two poles, for a permanent
fix.

The best diagnostic clue that I found before he arrived was to measure
between the two 100A fuses at the main panel, where this showed 0v instead
of 240v. The reason I still got 123v from between each phase and ground, he
explained, was because of back-feeding from the house circuits.

Tip: keep your trees trimmed near the phone poles, and keep an eye on your
neighbors trees!


Exactly. One of the legs (sometimes but incorrectly called 'phases')
was open.

The two legs, with 230 volts between them are actually the two ends of
a single 230 volt transformer winding; on the pole or underground etc.
The middle or centre point of that winding is the zero or neutral
point. A neighbour had the identical problem with the 230/115 volt
service to his garage. Broken connection at the pole transformer. He
couldn't figure why his 115 volt lights worked but nothing 230 volt
would work!

In non North American jurisdictions several actual 'phases' are
sometimes brought into domestic/residences etc.
In the Middle East my son had 230 volt 3 phase main circuit breaker
panel in his 'villa'.

In Malta the three phases and neutral (4 wires) went along the street
on wall brackets and a different phase (and the neutral) were tapped
into each house!

And over in, for example, the UK everything is 230 volt; no 115 volt
(except in certain special and unusual cases).

Here, in Canada three wires come into house one being the neutral. The
other two being the 230/115 volt legs as described by the OP.

Hmmm,
Pole? I don't see any pole in my neighborhood. Power, phone, cable, all
are under ground. Nothing overhead. 4 wires, one is ground.