Apprentice path · Stage 1: Staying alive on the job · Lesson 1

What electricity does to a body

Your body can become part of the circuit, and once current is flowing through you, you cannot simply decide to stop it.

Why this matters on the job

People think a shock is like a static pop off a door handle. It is not. Current going through your chest can stop you breathing, and the burn you can see on your hand can be the small end of damage that runs deep inside your arm.

How to think about it

  1. Understand that current needs a path, and your body can be that path.
  2. Remember your muscles can clamp shut, so letting go may not be a choice you get.
  3. Know that a shock across the chest can disrupt your heart and your breathing.
  4. Treat every burn as possibly deeper than it looks.

Worked through

Three things decide how bad a shock is: how much current, what path it takes through you, and how long it lasts. A small current across one finger for an instant, and a larger current from one hand through your chest to the other hand for several seconds, are not the same event at all. Wet or damaged skin makes it easier for current to get in, so the same contact is worse on a sweaty day than a dry one.

Check yourself: Two workers touch the same energized part. One gets a jolt through a fingertip. The other grabs it with one hand while the other hand is on grounded metal. Why is the second one far more serious?

Answer: Because the current path runs across the chest, through the heart and lungs, instead of staying in one finger.

Severity is about current, path and time -- not just voltage. The path is the part beginners never think about. Hand to hand, or hand to foot, puts your heart in the circuit. One fingertip does not.

Watch out for: The mistake is judging a shock by how much it hurt. Pain is not the measure. A shock that hurt less can be doing more, and damage under the skin does not announce itself.
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Written from the owner's poster for this lesson. Nothing added beyond what the poster states.

Written for Texas apprentices as free study material. The Texas apprentice licence is an application, not an exam (Occupations Code 1305.161), and nothing here counts as apprenticeship hours or continuing-education credit. VoltMark is not affiliated with, endorsed by, or sponsored by NFPA, PSI, TDLR, or any state or local licensing authority. Always follow your employer's safety programme and your supervising electrician.