Electrical Safety Hazards in Automotive Batteries - Coventry U

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Discussion Overview

The discussion revolves around the safety hazards associated with automotive batteries, particularly focusing on the inherent risks despite their nominally safe voltage of 12 V d.c. Participants explore various aspects of electrical safety, including potential hazards during charging and the physiological effects of electric current.

Discussion Character

  • Exploratory
  • Technical explanation
  • Homework-related

Main Points Raised

  • One participant notes that charging an automobile battery releases hydrogen gas, which poses an explosion risk during jump-starting if connections are made improperly.
  • Another participant discusses electrocution risks, highlighting that it can occur due to resistance heating or high current density affecting the heart, with skin resistance serving as a primary defense.
  • A claim is made that automobile batteries have very low internal resistance compared to carbon-zinc batteries, allowing them to deliver significantly higher currents, which increases the risk of burns from accidental short circuits.
  • One participant suggests that at higher voltage levels, electricity can break down skin insulation, leading to electrocution, although this is not directly applicable to the 12 V d.c. automotive battery.

Areas of Agreement / Disagreement

Participants express various viewpoints on the risks associated with automotive batteries, with no consensus reached on the primary hazards or the mechanisms of electrocution. The discussion remains unresolved regarding the specific safety implications of the 12 V d.c. automotive battery.

Contextual Notes

Some claims depend on assumptions about skin resistance and the conditions under which electrocution may occur. The discussion does not resolve the complexities of electrical safety in automotive contexts.

Alireza
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Hi Guys; as you can see I'm very new;)
I'm studying in Coventry University, and I need urgent help[b(]

I have to do a course work about Electrical Safty which I have no clue about it.

I was wondering if you guys can give me a link or some information about my question, it will be appreciated.


the main question which I have to write about it (around 100 worlds) is:


An automotive battery currently operates at a normal 12 V d.c. This voltage level is normally considered inherently safe. Explain why the automotive battery still represents a safty hazards.

Thanks in advance...:smile:
 
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When charging, an automobile battery releases hydrogen gas. When “jump starting” another vehicle, connect positive terminal first and than connect to a frame member at some distance from the battery to avoid an explosion from possible sparking when the connection is made.

As far as electrocution, it occurs due to “cooking” via resistance heating, or by having sufficient current density passing through the heart. There may be nerve stimulation (let go threshhold)but I believe that is much less a factor as compared to alternating current in the 50-60hz range

A person’s skin resistance is the primary defense against electrocution. If one abrades the skin to remove dead cells, that resistance will be about 1000 ohms. It will be the same whether measuring from toe to finger or from digit to digit on the same limb.

What makes an automobile different from an old-fashioned carbon-zinc battery is that it has very low internal resistance. If a carbon-zinc battery of twelve colts is short-circuited, its high internal resistance will limit its current flow to several amperes, whereas the automobile battery can provide upwards of 300 amperes for a considerable period of time.

The most likely electrical hazard associated with an automobile battery, is to be burned by a tool accidentally laid across its terminals, which will be heated to high temperatures very quickly. Four or five batteries connected in series can be used to weld metals.

Skin resistance will prevent physiological damage to the body, by limiting current flow to the mili-amp range. There is only one possible way I can think of to electrocute someone. If a person has an exposed conductive path to the heart, as one might have during a medical procedure, the heart may be caused to fibrillate.
 
WOW, I will make it short and simple. At higher voltage levels the electricity would be able to break down the insulation of your skin, enabling electrocution.
 
The Colt is a unit of electro-motive force honoring the famous Italian physicist, Alessandro Colta.
 
<< duplicate post deleted by berkeman -- see abdullah's separate thread about safety issues >>
 
Last edited by a moderator:
berkeman said:
<< duplicate post deleted by berkeman -- see abdullah's separate thread about safety issues >>

abdullah, welcome to the PF, but we have strict rules about duplicate/multiple posts. The separate thread that you started with the same text that you posted here in post #6 is the correct place for that different discussion to go on.

EDIT - I also moved your thread to the Engineering Homework Help forums, where all posts about homework and coursework should go. The PF guidelines and rules are very explicit about this.
 
Last edited:

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