Oliver Walker died after grasping the modified desk lamp in a caravan where he kept his toys at his home in Keighley.
Bradford coroners court heard today (Tuesday) how the youngster's mother Charlotte frantically tried to perform CPR on him on top of a hay bail after finding him grasping the appliance on the floor of the caravan on March 13, 2018.
However, efforts were in vain as Oliver was rushed to Airedale Hospital but sadly pronounced dead.
The tragedy caused the coroner to issue a plea for parents to check old electronic appliances to prevent other needless deaths.
Coroner Martin Fleming said Oliver has been found in the most "distressing circumstances imaginable" in the caravn, which his parents Charlotte and Andrew, and younger sister, were using while their farmhouse was under renovation.
The desk lamp, which had never been seen by the family before, had been modified for use with only a 12v supply bypassing a transformer in the base. However, the mains supply to the caravan was the standard 240v used for household sockets.
It's believed modification to the device had been carried out by an unidentified 'competent amateur'.
Mr Fleming said: "We don't know the individual who has done that or the reason. No mother or father should have to find their little boy in these circumstances."
A statement from Oliver's mother Charlotte read to the court described how she originally thought he was "playing about".
"Ben called 999 and I started CPR. I carried on until the paramedics took over.
"The lamp, I had never seen it before. The only thing I can think of is the lamp came with the caravan."
Following the tragedy, an investigation carried out by West Yorkshire Police determined there was no third party involvement.
The coroner recorded a narrative verdict and urged the public to check old electronic appliances.
Mr Fleming said: "He was such a much loved son, brother and nephew. He was a lot of things to a lot of people.
"[Oliver] was a bright little boy with intelligence beyond his years. It has and continues to leave a massive void in all of your lives."