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Discussion Starter · #1 ·
I was asked to perform a grounding system test in a dialysis patient care areas per NFPA 99, 4.3.3.1. I am completely lost as to how to perform this testing properly, what tester to use and how to document it correctly. Any help in pointing me in the right direction would be greatly appreciated.
 

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I was asked to perform a grounding system test in a dialysis patient care areas per NFPA 99, 4.3.3.1. I am completely lost as to how to perform this testing properly, what tester to use and how to document it correctly. Any help in pointing me in the right direction would be greatly appreciated.
I have the Standard in my office I will look when I get in, while we had done this in the past it has been a while.

For the liability involved you MIGHT want to

1. Hire a testing firm that has the equipment and expertise.
2. Do a lot of google searching and reading.

One part of the Standard (I BELIEVE) requires meters that have been calibrated. Few electricians do this on a regular schedule as mandated.
 

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One part of the Standard (I BELIEVE) requires meters that have been calibrated. Few electricians do this on a regular schedule as mandated.
Brian is correct. We use a Fluke Bio Tek safety analyzer and send it in yearly for calibration. They send us a notice and it runs $150.00.

If you have not done it before and don't expect it to be a regular service you will provide it is probably best to sub it out to a testing group.

SQ D will do it if there are no other local outfits.

Roger
 

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Discussion Starter · #9 ·
The testing company is currently doing the testing and we are getting readings up to 3 ohms. We have dedicated ground for each receptacle all the way back to the panels. Can't figure out why we are not getting the readings we are suppose to.


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The testing company is currently doing the testing and we are getting readings up to 3 ohms. We have dedicated ground for each receptacle all the way back to the panels. Can't figure out why we are not getting the readings we are suppose to.


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Dedicated grounds = higher ground resistance

Do the math resistance per foot by the footage. I assume #12 AWG.
 

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Discussion Starter · #12 ·
Bad Electrician: #12 wire is correct. We are going to have to change out to #10 AWG.

Fibes: Yes raceways are metallic.

Correction: we are getting 0.3ohms. NOT 3ohms


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Brian, NFPA 99 sets the limit at .2 ohms for existing spaces and .1 for new.

WBC, what are they using for the ground reference point?

Roger
I was wondering what the spec.s said, ideally if they are given a reference point it would seem the enginees should specify branch circuits over a certain lenght should be #10 or larger.

To the OOP Is this for all receptacles or just in surgery, with isolation panels.
 

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Discussion Starter · #16 ·
Roger: The building structure was used as a reference point.

Bad: The specs didn't call out to increase the wire size after 'x' amount of feet. The panel schedules however called out for #12 AWG. Before installation we contacted the engineer and they said that each gfci receptacle will need a dedicated circuit, neutral and ground. As well as an additional equipment grounding conductor used just to bond at all junction boxes. We asked, since there is an additional ground in the pipe then we need to install Isolated Ground GFCI receptacles? Engineer's response was no, IG GFCI receptacles is not necessary.


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Roger: The building structure was used as a reference point.

Bad: The specs didn't call out to increase the wire size after 'x' amount of feet. The panel schedules however called out for #12 AWG. Before installation we contacted the engineer and they said that each gfci receptacle will need a dedicated circuit, neutral and ground. As well as an additional equipment grounding conductor used just to bond at all junction boxes. We asked, since there is an additional ground in the pipe then we need to install Isolated Ground GFCI receptacles? Engineer's response was no, IG GFCI receptacles is not necessary.


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So you installed parallel #12 AWG EGC's? Depending on the size of the facility, seems the logical place to measure from is the Neutral Ground Bond in the SDS. But since there is no IG, all metallic components are common from the receptacles back to the SDS it seems (Depending how far away the reference point is) the impedance would be low?
 

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Discussion Starter · #19 ·
Correct, parallel EGC's. After speaking to the testing company, these are the options they gave me and we tested.
1)Pigtail both EGC's and connect stinger to GFCI receptacles. (Got a passing reading less than 0.1ohms but I believe it is a code violation. Haven't been able to find the code reference)
2) install an IG GFCI receptacle and increase wire size to #10 AWG (Got a passing reading less than 0.2ohms but not very cost effective)



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I have never done this kind of work before so I'm trying to follow what's going on. If there is a .2 ohm standing requirement then this facility was never in compliance. If you have runs of 200 feet of #12 wire then your minimum resistance is something like .37 ohms which means that it should never have been done in the first place. Is this the situation and now you are having to go back and straighten it out?
 
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