Loop Impedance Test

[mbrooke]

That is not any proof at all.

In my opinion you are putting the cart ahead of the horse.

If you can't show a need or a result we should not be adding code requirements.

There are cases like this:

http://forums.mikeholt.com/showthread.php?t=165011

While in this exact instance we don't know what lead up to it, there have been many times where the EGC has been compromised since day one. Granted unqualified personnel play a role, but with loop testing the original installer is taken off the hook. Even an electrician in the haste of finishing a project might get called when terminating an EGC and then come back forgetting where he left off. Plausible with full panel board, all of us have seen connections that have not been properly tightened since day one.

 

[user 100]

There are cases like this:

http://forums.mikeholt.com/showthread.php?t=165011

While in this exact instance we don't know what lead up to it, there have been many times where the EGC has been compromised since day one. Granted unqualified personnel play a role, but with loop testing the original installer is taken off the hook. Even an electrician in the haste of finishing a project might get called when terminating an EGC and then come back forgetting where he left off. Plausible with full panel board, all of us have seen connections that have not been properly tightened since day one.

But again, what would happen if the egc is compromised later, thus making all the expensive ELIT worthless? And also, while its true that some egcs aren't terminated correctly at installation, how would we be certain that the ELIT would performed correctly or if at all?

 

[mbrooke]

But again, what would happen if the egc is compromised later, thus making all the expensive ELIT worthless?

Its takes the original installer off the hook.

And also, while its true that some egcs aren't terminated correctly at installation, how would we be certain that the ELIT would performed correctly or if at all?

Teaching in apprenticeships. Once a skill is taught early and well it becomes a valuable tool. Another option is a report to the inspector.

I sense a lot of doubt and trust with what people will do in the field, that is itself a red flag...

 

[iwire]

There are cases like this:

http://forums.mikeholt.com/showthread.php?t=165011

While in this exact instance we don't know what lead up to it, there have been many times where the EGC has been compromised since day one.

So you are providing an accident at an old existing installation that we do not have any details of, to support your claim we need loop impedance testing for new installations.

 

[mbrooke]

So you are providing an accident at an old existing installation that we do not have any details of, to support your claim we need loop impedance testing for new installations.

As I said, its more of an example. We dont know what really happened, but I do know we have all seen poor terminations since day one.

 

[DrSparks]

Ok, a few points to make about this thread, which shouldn't even exist!

1. I'm not buying a meg-ohmmeter.

2. All the EGC needs to do in residential applications is facilitate a short circuit in the event of a ground fault, rendering the test pointless.

3. A bad termination will either show up as open or closed in a continuity test. You could get a good test result if you, for example, had a ground splice that was loose in the wirenut, but when thousands of amps are pulled through in a ground fault event, the splice would be blown apart, rendering the test pointless.

 

[mbrooke]

Ok, a few points to make about this thread, which shouldn't even exist!

1. I'm not buying a meg-ohmmeter.

2. All the EGC needs to do in residential applications is facilitate a short circuit in the event of a ground fault, rendering the test pointless.

3. A bad termination will either show up as open or closed in a continuity test. You could get a good test result if you, for example, had a ground splice that was loose in the wirenut, but when thousands of amps are pulled through in a ground fault event, the splice would be blown apart, rendering the test pointless.

An true EFLI meter will actually give you a reading in ohms using line voltage and current. Most questionable items will show up since the tester will actually pass a controlled current, not just a few volts to measure resistance.

To me an EGC is there for life safety, so making sure it will do its job is essential.

 

[DrSparks]

An true EFLI meter will actually give you a reading in ohms using line voltage and current. Most questionable items will show up since the tester will actually pass a controlled current, not just a few volts to measure resistance.

To me an EGC is there for life safety, so making sure it will do its job is essential.

Well, then that would be a valuable test, but to require it in the NEC? I know I could not afford to purchase such a device today. If industry standard practices are used, you should not have doubt that the EGC is intact. Your point is valid, though.

 

[DrSparks]

I know a very inexpensive way to test your EGC! It involves a black wire and a bare copper or green wire and a pair of lineman's pliers! :lol:

 

[mbrooke]

Well, then that would be a valuable test, but to require it in the NEC? I know I could not afford to purchase such a device today. If industry standard practices are used, you should not have doubt that the EGC is intact. Your point is valid, though.

True, Industry standard practices usually produce the intended outcome but when they do not it goes unnoticed. Thats where my concern resides.

If curious this is how EFLI is usually carried out:


https://www.youtube.com/watch?v=IWNXVMwTozg

https://www.youtube.com/watch?v=F3rw1KwFboQ

 

[iwire]

I'm suggesting that the loop impedance tester be used as a tool to support the electrician working in the field. The end results will speak for it self going forward!!

So you want to add cost and work to everyone's installations only because you think its a good idea.

I can never get behind code changes based only on that.

 

[romex jockey]

The NEC , along with the manufacturers of larger GFP breakers BOTH require testing here>

230.95(C) Performance Testing. The ground-fault protection sys-
tem shall be performance tested when first installed on site.
The test shall be conducted in accordance with instructions
that shall be provided with the equipment. A written record of
this test shall be made and shall be available to the authority
having jurisdiction.

~RJ~

 

[iwire]

The NEC , along with the manufacturers of larger GFP breakers BOTH require testing here>

Yes and that testing has absolutely nothing to do with 110.7 nor the loop impedance test suggested by the OP.


As a side note, having been involved with countess jobs that had multiple GFP devices over a 1,000 amps I have never seen or heard of an AHJ asking for this testing or a record of same.

So sure, add another rule for testing that will generally be ignored.

 

[romex jockey]

Yes and that testing has absolutely nothing to do with 110.7 nor the loop impedance test suggested by the OP.

It has everything to do with it

110.3B comes into play here rather strongly

As a side note, having been involved with countess jobs that had multiple GFP devices over a 1,000 amps I have never seen or heard of an AHJ asking for this testing or a record of same.

So sure, add another rule for testing that will generally be ignored.

Rather you simply prove your ignorance of code (and older code at that) along with your states inept AHJ's ...


I suppose you start your wood stove with articles like >>>>

Performance Testing of Ground-Fault Protective Devices
Understanding NEC Art. 230.95 requirements

~RJ~

 

[sparks1]

Do you have any statistics or evidence:

1) That new, unmolested wiring is causing fires?

2) That these fires are caused by high impedance connections?

3) That requiring this loop impeadance test would reduce fires?

I read many posts here that concern ground fault resistance , GFCI , and Arc fault detection issues. The the list goes on and on .... I see electricians struggle every day to make sense of why that can't figure out the problem? They spend many hours pulling things apart trying to resolve these same old problems. They are left them guessing why they keep getting call backs from customer to fix the problems they thought they had fixed previously. They walk away stumped looking for a solution. Any competent electrician who can perform a Meg test would have no problem performing a loop impedance test to demonstrate that there work meets safe standards.

 

[sparks1]

So you want to add cost and work to everyone's installations only because you think its a good idea.

I can never get behind code changes based only on that.

It would save all kind of costs and we should think that's a good idea

 

[sparks1]

loop impedance tester

loop impedance tester

Give the AHJ proof that your installation is good and that all of your connections are secure. Electrical Inspectors and Fire Departments Nationwide should support this proposed idea. With the advancement in technology the loop impedance tester will save the electrician and the customer money by avoiding costly call backs. It gives insurance companies the documentation and a standard to lower home owner insurance premiums and the electricians insurance premiums. Electrical inspectors can not possibly manage to find all these problems during, in most cases, a walk though inspection and a Hail Mary Pass that everything going to be alright!!!. It promotes fire safety and protects the public. Don't let the word loop impedance scare you away it's a very simple test and a very useful tool for troubleshooting.
There has never been a greater need for this type test and ignorance may have put it down in past proposals??? If it helps the industry then I'm all for it ... bring it on!!!!

 

[user 100]

I read many posts here that concern ground fault resistance , GFCI , and Arc fault detection issues. The the list goes on and on .... I see electricians struggle every day to make sense of why that can't figure out the problem? They spend many hours pulling things apart trying to resolve these same old problems. They are left them guessing why they keep getting call backs from customer to fix the problems they thought they had fixed previously. They walk away stumped looking for a solution. Any competent electrician who can perform a Meg test would have no problem performing a loop impedance test to demonstrate that there work meets safe standards.

I think your really reaching here. Still no proof of need, nor a reliable way to show that this testing would be done correctly or if at all.

 

[mbrooke]

I think your really reaching here. Still no proof of need, nor a reliable way to show that this testing would be done correctly or if at all.

Thats something Iwire has said before to the period. Im seeing that Iwire has a lot of influence on this forum...

 

[growler]

Does anyone know why this test has not been adopted as a standard to check wiring for new installation?

One of the substantial benefits of this test is that it verifies the integrity of the EGC, its confirms the installation is code complaint.

Do either of you guys actually perform these test on the new houses that you wire?

What are your findings so far? Cost & benefits.


You guys know that some states have very strict gun control and others don't and yet the number of guns used in crimes is about the same. More rules doesn't always make you safer at times it's just more time and money wasted with no benefits.