250.53A and new to correcting faulty building ground systems-Thx!

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docj67

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Hey thx for reading!

My understanding of 250 53 A is that

If it’s only one electrode then it needs to be 25ohms or less.

SO if your chosen primary electrode is greater then 25ohms and u cant easily measure then 2nd, what do you do?

I'd like to by an 800 dollar GEP rig but would prefer not to yet.

This article I read in ECM web mag
http://www.ecmweb.com/content/who-cares-about-25-ohms-or-less
and the last hr I just spent reading article 250 up to 250.80 seem to suggest that multiple grounding electrodes that meet code are how it's done if you cant measure the resistance of one Grounding Electrode.


If there’s one ground electrode w resistance > 25 ohms how many supplementals do you need and I believe the answer is one.

Thx so much
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
The code only requires a single electrode in most cases however you are required to have a second electrode if one of the electrodes is a water pipe. If one of your electrodes is a ground rod and you do not have less than 25 ohms you're required to put in a second rod. There is no requirement to actually meet 25 ohms if you have two rods. So your best bet if you are using ground rods is just put a second rod and be done with it.
 

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
As Bob said, simply add a rod and go to your next job.

Roger
 

infinity

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Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Hey thx for reading!

My understanding of 250 53 A is that

If it’s only one electrode then it needs to be 25ohms or less.

SO if your chosen primary electrode is greater then 25ohms and u cant easily measure then 2nd, what do you do?

I'd like to by an 800 dollar GEP rig but would prefer not to yet.

This article I read in ECM web mag
http://www.ecmweb.com/content/who-cares-about-25-ohms-or-less
and the last hr I just spent reading article 250 up to 250.80 seem to suggest that multiple grounding electrodes that meet code are how it's done if you cant measure the resistance of one Grounding Electrode.


If there’s one ground electrode w resistance > 25 ohms how many supplementals do you need and I believe the answer is one.

Thx so much

The 25 ohms or less applies only to the electrodes in the section you've stated 250.53(A) which are rod, pipe and plate electrodes. So as Bob and Roger have said just install two electrodes and forget about testing. If you had a CEE then that would be the only electrode required if it's the only one present.
 

docj67

Inactive, Email Never Verified
Thx so much guys! Grateful for this forum

Thx so much guys! Grateful for this forum

Thx so much guys! Grateful for this forum.

The 25 ohms or less applies only to the electrodes in the section you've stated 250.53(A) which are rod, pipe and plate electrodes. So as Bob and Roger have said just install two electrodes and forget about testing. If you had a CEE then that would be the only electrode required if it's the only one present.
 
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