Category:Electric Safety

ELECTRICAL SHOCK AND THE HUMAN BODY

IN MODERN COUNTRIES, WORKSHOPS, OFFICES, CLASSROOMS OR THE WORKPLACES, IT IS FORBIDDEN TO WORK ALONE WHEN WORKING WITH

EQUIPMENT, ESPECIALLY IF IT UTILIZES THE ELECTRICAL MAINS SUPPLY OR IF THE VOLTAGE IS HIGHER THAN 24V. IF WORKING ALONE, IN THE

EVEN OF AN ACCIDENT, SHOULD YOU RECEIVE AN ELECTRIC SHOCK OR BURNS, THERE WOULD BE NO-ONE NEARBY WHO COULD HELP YOU.

VOLTAGE SUCH AS DOMESTIC AC MAINS VOLTAGE OR VOLTAGE HIGHER THAN 24V CAN RISE TO PARTICULAR HAZARDS. THE HUMAN HEART

IS A MUSCLE AND HAPPEN TO BE MOST SUSCEPTIBLE TO STIMULATION AT AN APPLIED FREQUENCY OF ABOUT 50-60Hz, WHICH HAPPEN TO BE

THE MOST USED FREQUENCIES FOR MAINS SUPPLIES AROUND THE WORLD. DC VOLTAGE ABOVE A FEW VOLTS IS DANGEROUS.

THE EFFECT OF ELECTRIC SHOCK ARE A COMBINATION OF THE VOLTAGE LEVEL APPLIED (AMPLITUDE), THE CURRENT WHICH FLOWS THROUGH

(INTO) THE BODY AND THE TIME PERIOD OF THE SHOCK ITSELF.

ASSUMING THAT AN UNFORTUNATE PERSON PICK UP OR TOUCH A “LIVE” ELECTRICAL CIRCUIT, TYPICAL EFFECTS ON THE VICTIM ARE:

1mA TINGLING.

9mA PROBABLY ABLE TO RELEASE THE DEVICE OR CIRCUIT.

16mA BORDERLINE ON ABILITY TO DROP THE FAULTY DEVICE.

25mA PROBABLY UNABLE TO RELEASE THE DEVICE TO ESCAPE FURTHER ELECTRICAL SHOCK.

16 - 50mA PAIN, POSSIBLE UNCONSCIOUSNESS. POSSIBLE PROBLEM WITH HEART AND RESPIRATION FUNCTIONS IN THE FUTURE.

>100mA VENTRICULAR FIBRILLATION (HEART TREMOR). RESPIRATION PARALYSIS (ASPHYXIA, SUFFOCATION).

SEVERE SHOCKS AND BURNS.

POSSIBLE DEATH.

ACCIDENTAL HEATING CAN BE DANGEROUS TOO. ANY CURRENT PASSING THROUGH ANY MATERIAL IS SUBJECTING THAT MATERIAL TO HEAT DUE

TO ITS RESISTIVE LOSES. EXCESSIVE HEATING WILL CAUSE FIRE.

IN MANY COUNTRIES, LEGISLATION TO PROTECT HUMANS AND ASSETS DICTATE THE USE OF PROTECTION DEVICES TO PROTECT PEOPLES,

PROPERTIES AND EQUIPMENT.

PROTECTION DEVICES ARE DISCONNECTING THE SOURCE OF THE FAULT FROM THE PERSON BEING ELECTROCUTED OR FROM THE FAULTY

CIRCUIT OR DEVICE BEING SUPPLIED. PROTECTION DEVICES MUST ACT FAST TO DISCONNECT THE PERSON BEFORE PERMANENT DAMAGE.

TO SELECT A DISCONNECTION DEVICE, SEVERAL CHARACTERISTICS NEED TO BE TAKEN INTO ACCOUNT:

THE TIME IT WILL TAKE TO DISCONNECT THE SOURCE.

FROM WHAT TYPE OF FAULT (OVER-CURRENT OR LEAKAGE CURRENT) YOU WANT TO BE PROTECTED.

THE AMPLITUDE OF FAULT CURRENT WHICH WILL TRIGGER THE DEVICE.

IN CASE OF OVER-CURRENT LOAD PROTECTION, CIRCUIT BREAKERS ARE UTILIZED TO BREAK THE CIRCUIT SUPPLYING A LOAD.

IN CASE OF LEAKAGE CURRENT PROTECTION, EARTH LEAKAGE CIRCUIT BREAKER, OR GROUND FAULT CIRCUIT BREAKER ARE UTILIZED.

ALWAYS EQUIP YOU WORKBENCH WITH SAFETY DEVICE.

IN DOUBT, FIRST, PLEASE ALWAYS CONTACT YOUR QUALIFIED AND REGISTERED ELECTRICAL PRACTITIONER.

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