Page 85 - Between light and shade

Light, transparency and reflection

descent bulb. As a result, the fluorescent tube was
clearly the most ethical light source for diffuse
lighting, until the end of the 20th century.

Electricity generation, which was very local
at the beginning of the 20th century, gradually
became concentrated, with its distribution being
handled by autonomous networks of very high-
voltage cables to limit losses 98. Failures of these
local autonomous producers and successive
oil crises led, from the 1970s onwards, to the
interconnection and densification of networks.
Following interminable negotiations, a compro-
mise was reached, by virtue of which the miracle
of electricity delivered its power at a standard
voltage of 220 Volts in a star configuration, or
380 Volts in a triangular configuration 99. All
electrical appliances, including lights, are now
designed for these voltages.

The nature of light sources also shapes the
styles of building on the planet. Areas that are
still economically dominant (Europe, the United
States, in particular) and countries governed by
dictators with significant energy resources, like

98 It should be noted that the power is equal to P = V.I (Difference
in potential multiplied by the intensity of the electric current)
and that heat losses are equal to ΩI² (resistance Ω of the
conductor multiplied by the intensity of the electric current).
Therefore, with constant power carried, a 10-fold increase in
V results in a 100-fold reduction in losses.

99 IEC standard 60038, 6th edition, 1983, “IEC standard voltages”
takes these values to 230 V and 400 V.
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