The idea of a building a lethal electric fence in occupied territory seems unnecessarily vindictive and cruel. What was th German reasoning behind its construction? A smaller question I had was how it was electrified - were there multiple generating stations along its length? How did they prevent short circuits?
The electric fence made a lot of sense for the German occupiers, because the neutral Netherlands was the great gap in the Western Front. The Germans used the Netherlands to import many needed goods that were stopped by the Royal Navy blockade. Holland was also, however, the chink in Germany's armor. Spies and smugglers could slip in and out of Belgium easily, and at least 30,000 Belgians escaped across the Dutch border to go join King Albert and his liberation army. After the early German victories like the fall of Antwerp in 1914, many British soldiers escaped that way too; Edith Cavell, most infamously, was arrested for helping British troops escape via Holland.
Moreover, every Belgian who left was one less man who could be conscripting into Germany's factories. Germany squeezed its occupied territories dry during World War One to make up for its economic and manpower shortages. Finally, deserters from the German army would also make a break for the Netherlands. Having an escape route through the Netherlands was economically and military harmful, and politically embarrassing. Therefore they built the electrified fence - the "Wire of Death" - beginning in April 1915.
The wire let Germany control the border. The Dutch did not particularly mind either, because it got rid of smugglers, fugitives, and other nuisances who might drag them into a world war they were trying to avoid. German soldiers patrolled the fence, and in fact they were the real weakness, as those looking to get over for one reason or another found the best way was to bribe the guards. Two fences of normal barbed wire flanked the electric fence. On the whole, the fence seems to have been quite effective. Over 1,000 people died trying to cross it, either being shot by the guards or electrocuted by the wires.
For power the Germans used factories or generators located near the border, as this seems to have been before the advent of electric power-stations in large numbers. The Germans used "connection cabins" in abandoned houses to moderate the power. Don't ask me how that works. I'm a doctor(al candidate), not an engineer.
See also his article "A Second Belgian Front? The Belgian-Dutch Border during the First World War"