Loop Impedance Test

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DrSparks

The Everlasting Know-it-all!
Location
Madison, WI, USA
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Master Electrician and General Contractor
I guess it depends on the application and the equipment you are connecting to the grid. Do you think impedance to ground matters all that much in a house? I think a simple continuity test to ground is sufficient. We don't need stricter code IMO. We need stricter requirements to obtain a master electrician license! ;-)
 

mbrooke

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

iwire

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

Of course you have no info at all to show a need for this other than testing gives you the warm fuzzies. :D
 

sparks1

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Location
Massachusetts
Impedance matters a great deal! High impedance in a AC circuit causes over heating and can lead to fires. This is usually the result of poor connections in switch boxes or loose wiring at receptacle outlet.
 

iwire

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Massachusetts
Impedance matters a great deal! High impedance in a AC circuit causes over heating and can lead to fires. This is usually the result of poor connections in switch boxes or loose wiring at receptacle outlet.

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?
 

mbrooke

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That is not proof there is a need

110.7 does not require a test, if you feel it should put in a proposal.

Of course it doesnt require a test, it leaves it up to the electrician to find a way to determine compliance fulfilling that need. But in my mind I cant think of another way to confirm the EGC is intact. Keep in mind it has been missing EGCs that have been behind most GFCI mandates in the code.
 

sparks1

Senior Member
Location
Massachusetts
Of course you have no info at all to show a need for this other than testing gives you the warm fuzzies. :D

I have plenty of information to support the subject> It's a very simple test similar to a Meg test not complicated, if you can do a meg test you would have no problem performing an earth loop impedance test. Saves the electrician all kinds of time and you can record and document all the information.
Help to prevent fires. Could be used as proof for insurance companies for fire and flood damage. Could be done in conjunction with a megger test to improve standards in the industry.
 

mbrooke

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United States
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Technician
Yes, missing EGCs of appliances, you know those things that get damaged well after the installer has complied with 110.7. :D

They do, but code has also mandated GFCIs to hard wired appliances like pool pumps. So the concern in such is not just the cord/cord caps.
 

sparks1

Senior Member
Location
Massachusetts
That is not proof there is a need

110.7 does not require a test, if you feel it should put in a proposal.

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!!
 

DrSparks

The Everlasting Know-it-all!
Location
Madison, WI, USA
Occupation
Master Electrician and General Contractor
Impedance matters a great deal! High impedance in a AC circuit causes over heating and can lead to fires. This is usually the result of poor connections in switch boxes or loose wiring at receptacle outlet.

I think we were talking about impedance to ground on the EGC not the actual CCCs. A simple voltage test under load is all that's needed for that.
 

don_resqcapt19

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Location
Illinois
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retired electrician
It would add a lot of unnecessary costs to both the EC and the inspection department. Permit fees would have to increase by a substantial amount to cover the costs of the inspector being there to witness the tests. If he is not there, many would just fill out a test report without doing the tests.

I really don't see a need for this. Very few of the so called "fires of electrical origin" occur in dwelling units that are less than 20 years old.
 

user 100

Senior Member
Location
texas
It would add a lot of unnecessary costs to both the EC and the inspection department. Permit fees would have to increase by a substantial amount to cover the costs of the inspector being there to witness the tests. If he is not there, many would just fill out a test report without doing the tests.

I really don't see a need for this. Very few of the so called "fires of electrical origin" occur in dwelling units that are less than 20 years old.

:thumbsup:. LIT would be just another unnecessary expensive layer of "protection" that has no real value in new construction. And your right, there would no way we could verify true compliance.
 
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