[RE-wrenches] Starting fires for fun with string wiring

[Chris Mason]

Jeff,
In my limited knowledge of this issue, there is no doubt DC arcs have the
capacity to burn and are difficult to extinguish, and good wiring practices
are essential at these elevated voltages. However, you need to distinguish
between high temperature arcs which can burn, and Arc-Flash risks which
require special PPE and procedures. In order for the there to be a serious
risk of Arc-Flash, there has to be both a high voltage such as 480V and a
very high source current, in the order of 65,000 Symmetrical  Amperes, such
as you find near a HT/LT transformer. The extremely high current is what
creates the explosive heating of the air. Solar PV, being current limited,
has high enough DC voltages but does not have anywhere near the current
capacity and cannot cause arc flash.

Chris
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