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Please choose your project

Please choose your project. Review the Problem Statements Or think of your own (this has been done many times) Send me an email. Team emails are best. Set out some of your goals in the emaiil. Not too early to start picking hardware. Electrical Safety. Electrical Safety.

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Please choose your project

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  1. Please choose your project • Review the Problem Statements • Or think of your own (this has been done many times) • Send me an email. Team emails are best. • Set out some of your goals in the emaiil. • Not too early to start picking hardware.

  2. Electrical Safety

  3. Electrical Safety Should know better, trusts a state he cannot see http://www.youtube.com/watch?v=Hr4fywrPqq0 Lazy: http://www.youtube.com/watch?v=bX_ESSUlpYM Seriously? http://www.youtube.com/watch?v=cedGEI4xeOo People left behind: http://www.youtube.com/watch?v=UkxStI9RC http://www.youtube.com/watch?v=CX_BhJjSEGc

  4. Electrocution • Wall sockets are well within the death range • Without warning / No visible indicators • No time to move • Speed of Light • Undetachable • Immediate loss of control and consciousness

  5. Which of these is “live”?

  6. How wiring looks

  7. More wiring

  8. Which of these do NOT conduct electricity? • Metal • Glass • Wood • Water • Rubber • Plastic • Cloth • Rocks and Stones • Air

  9. They all conduct electricity • Because of salt and water vapor, which is always present Wood: http://www.youtube.com/watch?v=y1YcNT-v2ik Air: http://www.youtube.com/watch?v=IgnebrbWKKw

  10. AC or DC? Low voltage or High?

  11. PC Power Supply Output: +3.3V 27A, +5V 28A, +12V1 27A, +12V2 28A, -12V 0.6A, +5VSB 3A If your body or body parts present low-resistance opportunity, then the resulting high current can kill you, by burn, open wound, or cardiac arrest. A low-resistance opportunity is moisture, salt, sweat, polyester, metal, leather, etc.

  12. Some simple rules • Never work alone • Colors, markings, and the word of others mean NOTHING • Every wire is live • Visually assess / don’t believe the word of others • Test with a meter if possible • Unplug, switch off, disconnect • Recognize hazards and REPORT THEM

  13. 645 - 2222 Or 911

  14. Why?

  15. Why? ? Ungrounded case Grounded case 0 • What is a GFI? – are they safe?

  16. Ground Fault Interruptors • GFIs operate by measuring the current balance between two conductors using a differential current transformer. The device will open its contacts when it detects a difference in current between the live conductor and the neutral conductor. The supply and return currents must sum to zero; otherwise, there is a leakage of current to somewhere else (to earth/ground, or to another circuit, etc.). http://www.youtube.com/watch?v=LGiYlyo2-eQ

  17. Ground Fault Interruptors • A GFI will help to protect against electric shock where current flows through a person from a phase (live / line / hot) to earth. It cannot protect against electric shock where current flows through a person from phase to neutral or phase to phase, for example where a finger touches both live and neutral contacts in a light fitting; a device can not differentiate between current flow through an intended load from flow through a person.

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