Arkansas HVACR NewsMagazine November 2020

S tate, National, Chapter News Tech News

that when you increase the voltage you ALSO increase the amperage. Take a look at this chart from the CDC.

DOES THE VOLTAGE OR THE AMPERAGE KILL YOU? I hear the following phrase a lot. It’s the amperage that kills you not the voltage While there is truth to the statement, it is sort of like saying, “ I t’s the size of the vehicle not the speed that kills you when it hits you ”. OK, so that’s a pretty bad example ; but, hopefully, it gets the point across. BOTH of them are needed to cause injury or death and in the case of voltage and amperage the higher the voltage the higher the amperage. This statement about amperage being the real danger as led to many people inaccurately believing it is the size of a panel or the gauge of wire that makes something more or less dangerous-- which is 100% incorrect. Let’s take a quick look at OHM’s law – The resistance (ohms) of the human body depends on a lot of factors including things like the moisture content of the skin, what other objects the current path is traveling through, what path the current is taking through the body, etc… While the resistances vary based on these factors, Ohms law still holds true BRIAN ORR, HVAC SCHOOL Amps = Volts ÷ Ohms

Effects of Electrical Current* on the Body

Current

Reaction

1 milliamp

Just a faint tingle.

5 milliamps

Slight shock felt. Disturbing, but not painful. Most people can “let go.” However, strong involuntary

movements can cause injuries.

6-25 milliamps (women)† 9-30 milliamps (men)

Painful shock. Muscular control is lost. This is the range where “freezing currents” start. It may not be possible to “let go.” Extremely painful shock, respiratory arrest (breathing stops), severe muscle contractions.

50-150 milliamps