J
John Larkin
Guest
On Sat, 29 Jun 2019 23:27:16 -0000 (UTC), Jasen Betts
<jasen@xnet.co.nz> wrote:
But 120-N-120 at 10 amps per hot wire delivers 2400 watts. So does
240-N at 10 amps per wire.
The wires from the transformer down the street, to my house, are
120-N-120. I think the neutral wire is smaller than the hot ones. The
only copper penalty for the US residential distribution scheme is
adding 1 neutral wire to two hot ones, as compared to one neutral
added to three in europe.
The runs inside the house here, breaker panel to outlets, are short
and don't have much loss. Big loads are 240 anyhow, same as in europe.
In my old (1892) Victorian, one day some of the lights got extra
bright. I called PG&E and they rolled a truck but the crew didn't want
to believe me. I had to get a DVM and convince them the problem was
real. There was an open neutral connection on a pole outside. One leg
was up to almost 140, measured to my internal open neutral.
That house originally had gas lighting, then knob-and-tube wiring.
It's a miracle that it didn't burn down in the 100 years before I
owned it.
--
John Larkin Highland Technology, Inc
lunatic fringe electronics
<jasen@xnet.co.nz> wrote:
On 2019-06-29, John Doe <always.look@message.header> wrote:
Jasen Betts <jasen@xnet.co.nz> wrote:
For 115V you need wires 4 with times cross section to get the same
power loss as for and equivalent power load at 240V
I need a translation.
I'm talking about how much copper is needed to meet a fractional power
loss target in power distriution, somehow I seem to have substiuted
115 for 120
Ag assume a 1200W load,
At 120V that's 10A , and a 0.01 ohm resustiance in the wires dissipates 1W
At 240V that's 5A, and you can use thinner wires ( 0.04 ohms) and
still see 1W loss.
But 120-N-120 at 10 amps per hot wire delivers 2400 watts. So does
240-N at 10 amps per wire.
The wires from the transformer down the street, to my house, are
120-N-120. I think the neutral wire is smaller than the hot ones. The
only copper penalty for the US residential distribution scheme is
adding 1 neutral wire to two hot ones, as compared to one neutral
added to three in europe.
The runs inside the house here, breaker panel to outlets, are short
and don't have much loss. Big loads are 240 anyhow, same as in europe.
In my old (1892) Victorian, one day some of the lights got extra
bright. I called PG&E and they rolled a truck but the crew didn't want
to believe me. I had to get a DVM and convince them the problem was
real. There was an open neutral connection on a pole outside. One leg
was up to almost 140, measured to my internal open neutral.
That house originally had gas lighting, then knob-and-tube wiring.
It's a miracle that it didn't burn down in the 100 years before I
owned it.
--
John Larkin Highland Technology, Inc
lunatic fringe electronics