electrical safety in the laboratory l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Electrical Safety in the Laboratory PowerPoint Presentation
Download Presentation
Electrical Safety in the Laboratory

Loading in 2 Seconds...

play fullscreen
1 / 20

Electrical Safety in the Laboratory - PowerPoint PPT Presentation


  • 209 Views
  • Uploaded on

Electrical Safety in the Laboratory. Joshua D. Horvath Andrew J. Gellman Carnegie Mellon University Department of Chemical Engineering February 18, 2003. Accidents. Electrical shock from laser power supply Electrical shock from electrophoresis power supply. Introduction.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Electrical Safety in the Laboratory' - Thomas


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
electrical safety in the laboratory
Electrical Safety in theLaboratory
  • Joshua D. Horvath
  • Andrew J. Gellman
  • Carnegie Mellon University
  • Department of Chemical Engineering
  • February 18, 2003
accidents
Accidents
  • Electrical shock from laser power supply
  • Electrical shock from electrophoresis power supply
introduction
Introduction

Relationship between power,

current, voltage and resistance:

P = power (watts)

I = current (amperes)

V = voltage (volts)

R = resistance (ohms)

Example:

Heating tape uses 5 amps at 120 volts.

Power dissipated by this device is 600 watts.

ac vs dc electricity
AC vs. DC Electricity

Direct current (DC)

Alternating current (AC)

electrical components
Electrical Components
  • Capacitors
  • Resistors
  • Integrated circuits
measuring voltage
Measuring Voltage

Connect

Probe

Connect

Probe

+ 5V -

safety devices
Safety Devices

High Voltage Probe

  • Connects to normal multimeter.
  • Reduces voltage by factor of 1000.
  • Should only be used with training or assistance.
  • Dangerous if used improperly. You could be KILLED.
measuring current dc
Measuring Current (DC)

Connect

Probe

Connect

Probe

+ 5V -

safety devices9
Safety Devices

Clamp-on Ammeter

  • Measures AC current through a single conductor.
  • Does not work for DC current.
  • If both wires (positive and negative) pass through the clamp, no current reading is possible.
lab equipment
Lab Equipment

Power requirements (input)

lethal electricity
Lethal Electricity

Chart below assumes 1 second hand to foot

exposure to 120 volt, 60 cycle AC power supply.

Laboratory wall outlets provide 20,000 mA !!

safety devices12

New fuse

Blown fuse

Safety Devices

Fuses

  • Protect electrical wiring from carrying too much current.
  • Protect malfunctioning equipment from drawing too much current.
  • Conductor melts if too much current flows through fuse.
  • Can only be used once.
  • Always use the correct fuse.
safety devices13
Safety Devices

Circuit Breakers

  • Protect electrical wiring from carrying too much current.
  • Mechanical switch is driven by an electromagnet.
  • Can only be reset many times.
safety devices14
Safety Devices

Circuit Breakers (in action)

safety devices15
Safety Devices

Circuit Breakers

  • How much equipment can one 20A circuit breaker handle?
  • Not enough to bake an entire vacuum chamber.
safety devices16
Safety Devices

Circuit Breakers

  • One circuit breaker may cover many electrical receptacles in a lab.
  • Receptacles in some labs are labeled with a number that corresponds to a circuit breaker.
preventing accidents
Preventing Accidents
  • Avoid contact with energized circuits.
  • Disconnect the power source before servicing or repairing electrical equipment.
  • Work with only one hand, keeping the other hand behind you or in a pocket.
  • If water or a chemical is spilled onto equipment, shut off power at the main switch or circuit breaker and unplug the equipment.
  • If an individual comes in contact with a live electrical conductor, do not touch the equipment, cord or person.
  • Disconnect the power source from the circuit breaker or pull out the plug using a leather belt .
preventing accidents18
Preventing Accidents

Extension Cords

  • Do not plug one extension cord into another extension cord.
  • Do not exceed safety ratings.
  • If cord is warm to touch, it is probably overloaded.
preventing accidents19
Preventing Accidents

Electrical Fires

  • Unplug equipment first.
  • Use dry chemical fire extinguisher.
  • If fire is large, unplug equipment and call fire dept.
  • Never use water!!
conclusions
Conclusions
  • Be careful with electricity.
  • Ask someone for help if you are unsure.