Lethal metal

Originally Posted By: brian winkle
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OK here’s one for you to think about. I just returned from an older home that had just been sold, the new owners were preparing for move in. There were lots of signs of amateur wiring from several eras. I was called there to disconnect a cooling unit so the roofers could remove the unit.


The new owners also wanted me to look at some work they needed done inside. In the laundry there was a 3 wire dryer recep surface mounted in a metal box with a metal wall plate. As a habit, I always hold my volt tick up to any metal before I touch it. This one lit up 2 inches away. The wiggy read 240 between one leg and the metal plate, 120 between the plate and the water pipe. The 10/3 romex (no ground) had been forced into an old BX connector and was consequently nicked.


The point is, this house had just undergone a home inspection and it was not found. So I am not trying to tell anyone how to do their job, but rather offer this up as a possible suggestion that all exposed metal parts should be checked for voltage when dealing with ungrounded wiring. This could include boxes, conduits, faceplates, screws on plastic faceplates, sub panel covers and metal appliances. Like I said, this is a habit with me, the volt tick is in my shirt pocket all day and it only takes a second.

I only offer this as a suggestion, the consequenses of this fault could have been deadly, and it would have been so easy to detect. It would especially be in order when there is obvious non proffessional wiring present.

Brian


Originally Posted By: dsmith1
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Thanks Brian, good suggestion. The problem is that box was probably hidden behind the dryer during the inspection, and as inspectors we do not move appliances or furniture to inspect. I like you suggestion and will do it when possible.


David


Originally Posted By: Len Taylor
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What amount of current would be lethal? I am interested in this because some people I have met use two fingers to test for voltage.


Originally Posted By: rcooke
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Len Taylor wrote:
What amount of current would be lethal? I am interested in this because some people I have met use two fingers to test for voltage.

I worked with another Sparky that had such dry skin and high resistance he used to wet his fingers to test 600 volts .
Me I can feel 26 volts My hands are usually damp.

The amount of current to be lethal is minuet (very small) .
It is the voltage that is required to send the current through a vital part of the body.
This can vary from one person to another .
I do belive under the correct circumstances that 26 volts can kill .
Electricity should be treated with the utmost respect at all times
Unfortunately many feel they can do as they wish with the wiring in a home and you could have found just one more example of it .
Thanks for the heads up.


--
Roy Cooke Sr.

http://Royshomeinspection.com

Originally Posted By: bsumpter
This post was automatically imported from our archived forum.



http://www.nachi.org/bbsystem/usrimages/P/PA110088.JPG ]


Just one of many electrical challenges found during this inspection.


--
"In the fields of observation, chance favors only the mind that is prepared"

Louis Pasteur

Originally Posted By: jkormos
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It is the amperage and not the voltage that will curl your hair. And I too also keep my handy little volt stick in my shirt pocket.



Joe


Originally Posted By: rcooke
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jkormos wrote:
It is the amperage and not the voltage that will curl your hair. And I too also keep my handy little volt stick in my shirt pocket.


Joe

Sorry Joe I have to disagree.
Joe have you ever touched a spark plug .
Joe how much amperage does it take to kill a person .
Voltage is the push low voltage no push.


--
Roy Cooke Sr.

http://Royshomeinspection.com

Originally Posted By: Greg Fretwell
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“Kill” is up around a quarter of an amp. In the 1/10th of an amp range you can grab something and not be able to let go. Below that are various degrees of whacking your elbow against something, punching yourself in the nose and falling off the ladder.


When you get over a half amp you start seeing cooked flesh.


Originally Posted By: jkormos
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Hi Roy, check out these links


regards

Joe

http://fins.actwin.com/aquatic-plants/month.9901/msg00063.html

http://www.control.com/1026156232/index_html

http://www.madsci.org/posts/archives/aug98/899698536.Eg.r.html

http://www.newton.dep.anl.gov/askasci/phy00/phy00293.htm



Question - What equations do I use to find out the resistance of the


human body to electricity, and further how would I go about solving how


much current is needed to kill a human? I know the answer to the second


part is .07 Amps but how do we get that figure?


Charles,

If you are considering only DC electricity, the kind from a car battery, the
formula for resistance is voltage across the body divided by resulting
current through the body. Because the body is so big, however, it depends
on where you attach the electrodes.

If the electricity flows from the thumb to the pinky of the same hand, only
the flesh of one hand is affected. Resistance will be fairly small. The
hand will burn before the person can be killed. If the electricity flows
from one hand to the other, the electricity has to flow through more flesh.
Resistance will be greater. Most of the electricity will flow near or
through the heart. It is very likely that the person will experience heart
failure. A current of .07 Amps is enough to cause this. The number comes
from experience, not calculations.

There is no formula for exactly how much current will kill a person. Every
body is built a little different. We can only know an average value. Any
electrician will tell you not to worry about that value. When working with
electricity, it is best to prevent it from flowing anywhere beyond one hand.
A small amount of electricity in the brain can kill you. If not enough for
death, it can damage the brain or at least cause an extreme siezure.
Electricity through the heart can stop the rhythm, preventing the blood from
flowing correctly. This is the most common cause of death due to
electricity. Keep one hand in your back pocket, or strapped behind your
back. Never use both hands when more than just a few flashlight batteries
are involved.

Dr. Ken Mellendorf
Illinois Central College


Originally Posted By: rcooke
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Thanks Greg I new that .


It is so strange to me that so many have just a little knowledge and I feel they tend to spread false information.


Under normal conditions it takes about 40 volts to over come the internal resistance of the human body.


As I said before I am extremely sensitive to voltage and can feel if sooner then most.


Many think it is higher current then that and a fuse would protect them.


Wrong


--
Roy Cooke Sr.

http://Royshomeinspection.com

Originally Posted By: Jay Moge
This post was automatically imported from our archived forum.



rcooke wrote:

.

The amount of current to be lethal is minuet (very small) .
It is the voltage that is required to send the current through a vital part of the body.
This can vary from one person to another .
I do belive under the correct circumstances that 26 volts can kill .
Electricity should be treated with the utmost respect at all times
Unfortunately many feel they can do as they wish with the wiring in a home and you could have found just one more example of it .
Thanks for the heads up.


a good friend of mine who's a retired navy seal parametic showed me how to "kill" an enemie with a 9 volt battery, 3 feet of copper wire and 2 sewing needles. induction is cool. he also attached the sensor of his volt stick to his electricians glove and it beeps when ever he gets near voltage when he doesn't want to. ![icon_cool.gif](upload://oPnLkqdJc33Dyf2uA3TQwRkfhwd.gif)


Originally Posted By: wdecker
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Getting back to the original point.


If I see evidence of bad electrical work (as you did, even before you found the 240 dryer outlet) I 'Recommend evaluation and repair by a licensed and insured electrical contractor'. Around here, by law, sparkys are required to call out and repair any problems they see, even it it is not the problem that they were called in for.

Example. Electrician called in to add branch circuit. He notices a double tap off the main disconnect to a sub panel for the added A/C unit. He must point out that this also need to be repaired and repair it. If the client will not pay for it or tells him no, he is REQUIRED to notify the local code people as to the violation.

I am not saying that this always done, only that the law requires it.

My point is that if I find multiple, stupid stuff, I list a couple of them in my report and hand the responsibility (and liability) over to the sparkys. They are the specialists, I am just a general practioner.


--
Will Decker
Decker Home Services
Skokie, IL 60076
wjd@DeckerHomeServices.com

Originally Posted By: rcooke
This post was automatically imported from our archived forum.



wdecker wrote:
Getting back to the original point.

If I see evidence of bad electrical work (as you did, even before you found the 240 dryer outlet) I 'Recommend evaluation and repair by a licensed and insured electrical contractor'. Around here, by law, sparkys are required to call out and repair any problems they see, even it it is not the problem that they were called in for.

Example. Electrician called in to add branch circuit. He notices a double tap off the main disconnect to a sub panel for the added A/C unit. He must point out that this also need to be repaired and repair it. If the client will not pay for it or tells him no, he is REQUIRED to notify the local code people as to the violation.

I am not saying that this always done, only that the law requires it.

My point is that if I find multiple, stupid stuff, I list a couple of them in my report and hand the responsibility (and liability) over to the sparkys. They are the specialists, I am just a general practioner.


I agree I do the same find some concerns Hand it to the purchaser.
Requires immediate repair.
Jan 31 I did a home 8 inches of snow .
Could not walk the roof but swept two sections and saw the shingles where done .
Stated to the purchaser requires immediate repair or replacement .
I also wrote Chimney flashing requires immediate repair or replacement..
Got a call from the client last night .
We have had a lot of rain and the home he moved into last March suddenly lost a large wet section of the ceiling .
He had not done the roof or the chimney now he wonders where he can find a roofer to come and fix his roof.
Rain today and for the next 6 days it looks like .
You can tell them to fix it but many do not and they suffer the consequences


--
Roy Cooke Sr.

http://Royshomeinspection.com