Electrical Story of Mr. Black, Mr. White, and Mr. Ground
pick an appliance, say, the refrigerator for instance. Behind it is a
receptacle, which is required, and if it is properly wired, there are three
wires going to it: one black, one white, and one bare wire.
electrical panel there is a black wire connected to the breaker that takes
power to the refrigerator – we will call him Mr. Black. There is a white
wire that completes the circuit back to the electrical panel – let’s call him
Mr. White. The bare wire, hereafter known as Mr. Ground, is connected to
the round prong on the receptacle and connected to the ground in the electrical
want you to think of a two lane road with an emergency lane in the
middle. Mr. Black comes from the breaker, in the electrical panel, all the
way to the refrigerator. Let’s say the refrigerator needs four amps to
operate. Mr. Black is on one road. Mr. White completes the
circuit. He is on the other road. Now, Mr. Ground is on the emergency
road. He is there just for safety. He rarely ever does
anything. Mr. Black and Mr. White do all the work. Mr. Ground can sit
in his recliner all day long, watch T.V., use his iPod, and take a nap. He
is on duty 24/7. Mr. Black & Mr. White do get time off when the
refrigerator is not running.
let’s suppose that one day Mr. Black has an accident. Let’s say a
component goes bad, his insulation gets torn, and he is now touching a metal
part in the refrigerator. The amps go from four amps to five, ten,
fifteen, twenty, thirty, forty amps, or higher. Mr. Ground get knocked out
of his recliner, spilling his morning coffee all over him. He goes to the
electrical panel as fast as he can to tell Mr. Breaker to shut off. Mr. Breaker
thanks him for showing up and tells him, “Man, it was getting hot in
change the story for a moment. Suppose one day you pull the refrigerator
out to clean behind it and run over the male plug and break the ground prong
off, or you only have a two prong receptacle and use an adapter to be able to
plug the refrigerator in, or someone cut the prong off; I see it on drop
cords all the time. You have just fired Mr. Ground. He hasn’t had a
day off in years, so he takes off for the Bahamas. He is on the beach
soaking up the sun. If you ask Mr. Black or Mr. White if they miss him
they don’t. They complain that Mr. Ground doesn’t do anything – he is just there for safety.
the same thing happens to Mr. Black. He is now touching a metal part of
the refrigerator. Everything still works so he says he didn’t need Mr.
Ground anyway. He said he had heard the Mr. Ground was so bored the he was
thinking about putting in a putt-putt golf course.
suppose after a nice long shower, we decide to go to the kitchen for a nice
cool drink with no shoes on. You step on the ceramic floor and grab hold
of the refrigerator handle to open the door. You just took the place of
milliamps (mA) can cause harm, one hundred milliamps can be fatal. There
are one thousand milliamps in an amp.
Ground is just for safety – our safety!