Electricity Safety: AC & DC Current Limits for Intro Physics Labs

In summary, a forum member asked about the safe limits for AC and DC currents to be used in intro physics labs, and provided a link to a chart with current limits for various body effects. Other members advised to stay below 50V and not to get hung up on AC/DC, as the important factor is understanding the hazards and how to avoid them. They also cautioned against comparing human physiology with personal safety, as electricity can be dangerous.
  • #1
Gamma
357
11
I would like to ask the experienced experts about the safe limits for AC and DC currents to be used in intro physics labs. People say DC is dangerous because one can’t let go of the wire if the wire was carrying certain DC current.

Following link has a chart with current limits for AC and DC for various body effects. Do you agree with this chart?

http://www.allaboutcircuits.com/vol_1/chpt_3/4.html

Thank you!
 
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  • #2
I think that kind of advice is against the forum rules since if we give advice and you follow it and someone gets hurt you could sue and then Greg could have a problem. Sounds farfetched, perhaps, but it out litigious society you can't be too careful.
 
  • #3
Stay below 50V - in the US over that you need to be a Qualified Individual - basically meaning you have been trained sufficiently to be aware of the hazards in your work environment and understand how to avoid them.

AC / DC does not matter - do not get hung up in that. Voltage and Current do not get hung up on that ether!

The point in the post is that technically current is what does the damage - but it is like saying speed does not kill - it is the rapid deceleration. PLEASE do not confuse or compare human physiology with personal safety - ELECTRICITY can and will kill you.
 
  • #4
See phinds, we won't discuss this here. Ask an expert (not in internet forums) before you use anything that could be dangerous.
Windadct said:
AC / DC does not matter - do not get hung up in that. Voltage and Current do not get hung up on that ether!
It can matter, as a human has some capacitance against the environment and you get different effects in tissue if the current directions gets reversed frequently.

PLEASE do not confuse or compare human physiology with personal safety - ELECTRICITY can and will kill you.
Let's hope it won't...
 
  • #5


I would first like to commend you for considering safety in your physics lab experiments. Electricity can be dangerous if not handled properly, and it is important to be aware of safe limits for both AC and DC currents.

In regards to the chart provided in the link, I do agree with the general guidelines presented. It is important to note that these limits are based on the effects of electric shock on the human body, and they may vary slightly depending on factors such as individual health and body size. It is always important to exercise caution and follow proper safety protocols when working with electricity in a lab setting.

In addition to these limits, it is also important to consider other safety measures such as using appropriate protective gear, properly grounding equipment, and having a designated safety plan in case of emergencies. It may also be helpful to consult with experienced professionals or follow established safety guidelines for specific lab experiments.

Overall, I believe it is crucial to prioritize safety in any scientific experimentation, and being aware of safe limits for AC and DC currents is a necessary step in ensuring the well-being of yourself and those around you.
 

What is the difference between AC and DC current?

AC (alternating current) is a type of electrical current that periodically reverses direction, while DC (direct current) is a type of electrical current that flows in only one direction.

Why is it important to have current limits in intro physics labs?

Current limits help ensure the safety of students and prevent any potential accidents or injuries from occurring. They also help prevent damage to equipment and ensure accurate and reliable experimental results.

What are the commonly used AC and DC current limits in intro physics labs?

The most commonly used AC current limit is 0.5 amps, while the most commonly used DC current limit is 2.0 amps. These limits may vary depending on the specific equipment and experiment being conducted.

How are current limits determined in intro physics labs?

Current limits are determined by considering factors such as the voltage of the power source, the resistance of the circuit, and the capabilities of the equipment being used. Generally, the lower the voltage and resistance, the lower the current limit.

What precautions should be taken when working with electricity in intro physics labs?

Always wear appropriate protective gear, such as gloves and safety glasses. Make sure to follow all safety instructions provided by the instructor or lab manual. Do not touch live wires or equipment while it is connected to a power source. Always disconnect the power source before making any changes to the circuit. If unsure or uncomfortable, seek guidance from the instructor.

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