Sylvia Else wrote:
D Yuniskis wrote:
Sylvia Else wrote:
I have to phases of power supply to my house - so three power lines,
two phases plus neutral.

I suspect it is really "single phase" (think: center tapped
transformer) -- though in Oz they probably do things differently! :

I've on occasion wondered what would happen if we lost the neutral
line. It seems to me that we'd then have the voltage between the two
phases across two sets of appliances, one set attached to one phase,
and the other set attached to the other phase, with the two sets in
series as a result of their common connection to the neutral wire.
Since the two sets are unlikely to represent equal loads, the net
result would be a large overvoltage on one set of appliances.

"Large" is a relative term. Homes are typically wired to
try to distribute the loads roughly equally on the two
legs. And, REALLY BIG loads (e.g., air conditioner compressor)
tend to straddle *both*.

I imagine that's the case in terms of large potential loads, but if I
think about what's actually running in my house at the moment, apart
from a couple of lights, it'd be the refrigerator and my computers. I
don't know whether they're on difference phases, but if they are they'd
represent significantly different loads.

Exactly. And, those loads *change*. So, when the refrigerator's
compressor kicks off, *that* load is gone (here, refrigerator
sits between one leg and neutral; yours may straddle both legs?)