'Don't risk your life with kites'.
The power line company was shocked to find kite lines tangled around the power cables on the lower slopes of Castle Hill, Almondbury, with the kite cut away.
Engineers had to turn off supplies to local customers for 40 minutes to make the lines safe.
It has prompted a "don't risk your life" safety message from CE Electric UK, the subsidiary of Midamerican Energy Holdings which runs the electricity infrastructure of Yorkshire and Northern England.
Ann Walker, of the company, said: "Someone could have been killed.
"They must realise that electricity can travel down kite lines and it was a very foolish and dangerous thing to do."
Company engineers moved some overhead power lines on Castle Hill two years ago, to allow kite-flying in safety.
But they were unable to bury cables lower down the slopes and left those on poles between High Lane and Sharp Lane.
Ms Walker said: "No- one wants to stop the kite flying at Castle Hill, but no-one should go near power cables, no matter what the problem.
"If your kite becomes stuck in the lines or your football gets kicked into a sub-station, don't risk your life. Ring us and we will send out an engineer to do the job safely."
* Ring 0800 375675.