2/12/2007- QOD - Electrical

[Michael Larson]

Originally Posted by pabernathy

It only takes .005 MA to kill you........so basically lets do the math....

Well now you've stepped in it.

Equipment leakage current limits are different depending on equipment type and application. This doc describes the limits.
The smallest current limit is .010 mA and that is for medical equipment for a particular type of patient applied part.
By way of comparison your typical computer power supply can has leakage current limit of 3.5 mA max. allowed.

http://www.condorpower.com/public/condor/pdfs/An113.pdf

I used to do this type of testing and evaluation for a living and have been involved in elctrical safety for over 25 years.
Not pounding my chest just explaining why I know this.

[Paul W. Abernathy]

MY brother..............YOUR posts are SO important to this topic because you bring VERY...VERY valid points....and only through bringing them do we learn.

I am sure the other electricians can add here....as I have been brief on explaining it...but is more so why MARC stated it is useless in most cases in regards to electrical in the dwelling so to speak.

ALSO....it is important to understand TIMING....with all that said and done....BECAUSE we are such poor conductors and the earth is such a poor path.......all this translates into the OCPD never tripping.......because it NEEDS to see amps in excess of its rating to TRIP and in a normal breaker it can need to see 6 TIMES the rating to TRIP.....

This question SHOULD make people THINK about how electricity really works and why it can be dangerous....that was my overall goal.

[Paul W. Abernathy]

Micheal....I will be sending that DOCUMENT much like I did on the IDEAL one that I found to Mike Holt.....that statement has a BUNCH of ERRORS in it...

Are you telling me you think FAULT currents are SHUNTED to the EARTH via the Ground Rod in a house............I stepping in nothing.

Do you believe EVRYTHING you read as this myth has been around for years and years...in fact the article I submitted to MIKE HOLT which I will post was from IDEAL the makers of Ground Rod Testers and Test Equipment and they misunderstood the systems....and THEY MAKE THEM

[Paul W. Abernathy]

And here is the ORIGINAL article....remember this is from the MAKERS of the SureTest and Ground Rod Testing Devices....

EDIT: I can't find the original...I will find it and post it....BUT read the statements made by the industry leaders on these equipment and devices and THEN read Mr. Holts comments.

I sent this document to Mr. Holt..........because of all the wrong statements within it........this document also has some major incorrect statements in it....THANK you for posting it.

[Michael Larson]

Originally Posted by pabernathy

Micheal....I will be sending that DOCUMENT much like I did on the IDEAL one that I found to Mike Holt.....that statement has a BUNCH of ERRORS in it...

UL 2601-1 now UL 60601-1 is the UL standard for medical equipment. Yes errors exist in standards but the limits stated are correct in this case.

UL 950-1 now UL 60950-1 is the standard for information technology.

Originally Posted by pabernathy

Are you telling me you think FAULT currents are SHUNTED to the EARTH via the Ground Rod in a house............I stepping in nothing.

I only meant you stepped in when you stated that .005 mA could kill you. Do you have a source for that statement. Perhaps it was a typo.

Originally Posted by pabernathy

Do you believe EVRYTHING you read as this myth has been around for years and years...in fact the article I submitted to MIKE HOLT which I will post was from IDEAL the makers of Ground Rod Testers and Test Equipment and they misunderstood the systems....and THEY MAKE THEM

What myth? Did I miss a post. I will go back and reread. I was not addresssing ground rods only leakage current limits.

[Paul W. Abernathy]

I think my DECIMAL points are wrong...what we are talking about is 5MA for a GFCI to function.......in the use of a Ground Rod for a dwelling....

You are putting dedicated supplementary electrodes for voltage gradiants and so on in the same level......we are talking about the Ground Rod to a dwelling and its FUNCTION........

[Paul W. Abernathy]

Ahhh...leaking voltage is a totally different thing but it plays no ROLE in the functional use of a ground rod and it's intent and use.

Are you saying 5 MA could not kill you?

Lets not get people confused now Micheal.......Medical Equipment with a isolated ground and so on is a different subject. While it can PUT voltage on the grounding system...it will make an attempt to travel to the source and thus through proper bonding of the system and through a PROPER path to the origination point......so technically we could say the WHITE neutral wire in a panel should have some " GREEN" tape on it also.....( dont do that...was a metaphor )

[Paul W. Abernathy]

But I love it.......Keep it coming fella......IT's all GOOD.......but lets keep it to Dwelling fella...lol...not Medical Facilities...lol

[Michael Larson]

Originally Posted by pabernathy

Ahhh...leaking voltage is a totally different thing but it plays no ROLE in the functional use of a ground rod and it's intent and use.

I agree. I went off topic because of your kill you statement.

Originally Posted by pabernathy

Are you saying 5 MA could not kill you?

It sure can. I was reacting to your decimal point error which would be 5 micro Amps.

[Paul W. Abernathy]

lol....and rightly so...I type for CRAP.

I actually like the article ( to a point ) that you posted but if you read the first few lines it talks about the LOSS of the grounded conductor...and the same effects will take place on ALL metal equipment and will indeed leak but this still goes BACK to the source....

COULD it go back through the EARTH to the source....YEP it most certainly can if that is the only way for it to get back because of the loss of the Grounded Conductor in the system.....

Sad part is.......it will TRY but the path is SOOOOO poor it simply wont protect anything so effectivly the Ground Rod is NOT effective in that senerio...

Micheal...you have NO idea how I thank you for brining that up...it really ADDED to the topic....Richard you as well....WONDERFUL stuff

[Michael Larson]

That's is the beauty of NACHI.

Different backgrounds contributing to the common cause of educating.

[Paul W. Abernathy]

Yep.....for those justing reading these END examples....GO back and read this topic from the start to really GAIN something...not just the last few posts.

And.....ENJOY and feel FREE to jump in and add to it...

[Paul W. Abernathy]

Hey....Micheal inspired me to do some more checking on the STRAY voltage issue. Everyone knows ( I think ) that while the Ground Rod does not assist in anyway....the removal of stray voltage it is important to know HOW stray voltage can really get on the house system itself...

Ironcially since the Grounded Conductor going down your service drop or latteral is serving as the path back to the transformer..we all know that in the transformer you have a connection between the primary grounded conductor and the secondary grounded conductor....what this DOES is provide for stray voltage on the system and this can leak into the earth and be picked up by the pool systems bonding and so on.....interesting concepts here and WELL above the normal head of most electricians actually....

I then went searching for some articles and found this one.....VERY interesting article and I will post a link to it.....

I ironically enough the 5MA of a GFCI threshold may not kill you right away...it really depends on HOW good o contact you have and if the MA rises...at 10MA you are probably going to be TOAST regardless....

Anyway this is just a little light reading on a kinda...sorta variation of what Michael was stating....just not equipment related really...

Enjoy the read : http://www.mikeholt.com/documents/sa...rd/8-16-99.doc

[Paul W. Abernathy]

FYI- Micheal....THANK YOU.....I just wanted you to know I passed that article along to Mr. Holt and here is his comments

"This is so wrong. I'll write a newsletter with my comments and send it out to 40,000 electrical professionals."

See....I am not full of CRAP...tehhehehehe.....

Disclaimer - Sorry for the TEEHHEHEHE....please dont FLAME me as it is simply my way of expression and enjoyment in a field I simply LOVE.

FYI- Yes, I do idolized Mr. Holt....I inspire everyday to gain as much knowledge as this man has.

[Michael Larson]

Originally Posted by pabernathy

Enjoy the read : http://www.mikeholt.com/documents/sa...rd/8-16-99.doc

I did. I like the table on the last page. It will give many a better idea of the hazards involved.
BTW- 1 mA can be felt when it is applied to one's ear lobe which is very sensitive in most cases .(really depends on the resistance of the skin)