Loop Impedance Test

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ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min from the winged horses.
Occupation
Licensed Electrician
Inductive heating, power quality, voltage gradients, EMF, shock hazards...

Anyone with real world experience will tell you conduit heats up when the net current isnt zero.
One of our regular service accounts has some branch circuit hots and neutrals scrambled between conduits. No smoke, no fire, no shocks. Sure it needs to taken care of, but it has been that way longer than I have been alive.
 

iwire

Moderator
Staff member
Location
Massachusetts
Anyone with real world experience will tell you conduit heats up when the net current isnt zero.

Hmm, but if I recall correctly the CEC does not worry about net current until the circuits are over 200 amps.

Does that mean they do not have any real world experience or does that mean it's not that big of a deal?
 

iwire

Moderator
Staff member
Location
Massachusetts
You continue the claim all my facts are opinions. I have proof the back them up, but you refuse to accept it.

I refuse to accept the need for the things you want.

I refuse to believe the fact an item or test procedure exists is a reason to mandate into code


When Tony brought up RCDs you fled because you knew he would discredit your statement regarding nuisance tripping.

Tony asked me the exact same question not more than a couple of weeks ago, he asked I answered and then he asked again in this thread. I am not going to keep answering the same question.




Ditto when I posted docs to back up my statement magnetic trip provides arc fault protection from an NRTL standpoint.


I did not disagree with that view.

Part of the problem is you make your posts so damn long and covering so many topics in one post makes it very difficult to respond via moble.

I do see a lot of ego driven behavior on your part, however assuming so on my part is a mistake as that is not my intent. I am not driven by ego,

Perhaps you should do some more self examination. :D

Do I need to go back and quote how many times someone has said X will never work only to then post documentation proving it does?

For example, main RCDs you will tell me that the fact they use them in Europe is all the proof we need to justify main or sub main GFP here. That's your proof, that and your personal feelings.

When people point out that sub main GFP at the trip levels you advocate would cost the consumers more you simply ignore that or try to say troubleshooting won't be needed.



As I said, the statistics of tripping GFP and open EGC are out there.

That is not proof of a need for sub main GFP, I know you are sure it is but many of us experienced folks disagree.
 

romex jockey

Senior Member
Location
Vermont
Occupation
electrician
For example, main RCDs you will tell me that the fact they use them in Europe is all the proof we need to justify main or sub main GFP here. That's your proof, that and your personal feelings.

When people point out that sub main GFP at the trip levels you advocate would cost the consumers more you simply ignore that or try to say troubleshooting won't be needed]

2 or 3 50-60A 2 pole AFCI's would be far more economical than 30-40 individual AFCI's , providing the same protection

That this obviously flys completely over your head says you're not now, nor will probably ever view an install from an EC or consumer stance

~RJ~
 

romex jockey

Senior Member
Location
Vermont
Occupation
electrician
I refuse to believe the fact an item or test procedure exists is a reason to mandate into code

No, you simply refuse to acknowledge code, no matter how many times it is posted here Iwire

Inasmuch as unsubstantiated contrarians may abundantly proliferate the asci-sphere, i find it lowers the bar when a moderator engages in such behavior , especially in a premiere educational site....

~RJ~
 

sparks1

Senior Member
Location
Massachusetts
Of course. Our system was not so broken as to require AFCI's in the first place.

Nor do we need:

-Insulation testing
-Ground loop impedance testing
-Whole house GFP
-Gimmicky devices that detect heating at splices and wiring devices

We have a good, safe and reliable system that has worked for a long time now. The trouble starts when people invent and legislate products that are a solution to a problem that doesn't exist.

My ears are ringing!!! The problem does exists plenty as stated by professional who have replied to this post. Where's the proof that the current system is safe and reliable ???A fire developed in a panel just last week in my neighboor. The cause determined was loose breaker jaws. Anyone who has worked in the trade a long time has seen this problem happen countless times. ELit testing would pick out this problem before it occurs.
 

Tony S

Senior Member
Tony asked me the exact same question not more than a couple of weeks ago, he asked I answered and then he asked again in this thread. I am not going to keep answering the same question.

For the simple reason you can’t answer the question.

During my years of study, if I couldn’t answer a theoretical question I’d do some research and find an answer.

Design work isn’t a matter of joining the dots with wire of a certain size.

I have to guarantee:
The volt drop due to impedance won’t affect the operation of the circuit protection
The circuit protection is capable of performing its function
The protection will operate within specified times
 

iwire

Moderator
Staff member
Location
Massachusetts
The problem does exists plenty as stated by professional who have replied to this post.

OK, so if someone agrees with you they are a professional, if they do not what are they?


Where's the proof that the current system is safe and reliable ???

The millions of installations that have not had fires.

A fire developed in a panel just last week in my neighboor. The cause determined was loose breaker jaws.

A fire? really? Or just some melted plastic?

Anyone who has worked in the trade a long time has seen this problem happen countless times. ELit testing would pick out this problem before it occurs.

Actually it would not unless you are doing this testing monthly or weekly or daily.
 

peter d

Senior Member
Location
New England
My ears are ringing!!! The problem does exists plenty as stated by professional who have replied to this post. Where's the proof that the current system is safe and reliable ???A fire developed in a panel just last week in my neighboor. The cause determined was loose breaker jaws. Anyone who has worked in the trade a long time has seen this problem happen countless times. ELit testing would pick out this problem before it occurs.


Are you another engineer pretending to be an electrician? You know, like Mbrooke is doing.
 

peter d

Senior Member
Location
New England
I have to guarantee:
The volt drop due to impedance won’t affect the operation of the circuit protection
The circuit protection is capable of performing its function
The protection will operate within specified times

Thankfully I don't have to guarantee those things, and I'm happy that I don't.
 

romex jockey

Senior Member
Location
Vermont
Occupation
electrician
The volt drop due to impedance won’t affect the operation of the circuit protection

The circuit protection is capable of performing its function

The protection will operate within specified times

All of these can be read into our NEC Tony, however you'll find they go unacknowledged UNTIL a problem occurs

After which you'll find 20 page threads in pro forums berating those individuals who in fact did just that....

~RJ~
 

sparks1

Senior Member
Location
Massachusetts
For the simple reason you can’t answer the question.

During my years of study, if I couldn’t answer a theoretical question I’d do some research and find an answer.

Design work isn’t a matter of joining the dots with wire of a certain size.

I have to guarantee:
The volt drop due to impedance won’t affect the operation of the circuit protection
The circuit protection is capable of performing its function
The protection will operate within specified times

There's is no way that you can guarantee or even confirm that the circuit protection device even functions to trip. Since there is no ELit test
performed after the device has been installed to see if it's operating within manufacture specified time limits
 

user 100

Senior Member
Location
texas
There's is no way that you can guarantee or even confirm that the circuit protection device even functions to trip. Since there is no ELit test
performed after the device has been installed to see if it's operating within manufacture specified time limits

You are aware of the fact that you can perform a deliberate l>g test by simply tapping a hot and egc together aren't you? Short testing breakers that way isn't supposed to be done but if you must absolutely must know........

Despite some egregious and rare examples (FPE, Zinsco etc) most standard residential ocpds will quickly open in the advent of a l>g fault. The standard mag breakers are proven and get tested to the hilt-the science behind them is well established.
 

growler

Senior Member
Location
Atlanta,GA
A fire developed in a panel just last week in my neighboor. The cause determined was loose breaker jaws. Anyone who has worked in the trade a long time has seen this problem happen countless times.


Is the sky really falling or is this just a bird taking a dump.

For this example to have any meaning at all more information would be needed.

1. What is the age of the panel, when was it installed. New, 20 years ago, 40 years ago?
2. Was the breaker the correct size an type for the panel and conductor to be protected?
3. What was the extent of the damage?
 

mbrooke

Batteries Included
Location
United States
Occupation
Technician
Hmm, but if I recall correctly the CEC does not worry about net current until the circuits are over 200 amps.

Does that mean they do not have any real world experience or does that mean it's not that big of a deal?


Can you post what section you are referring to?
 

growler

Senior Member
Location
Atlanta,GA
Design work isn’t a matter of joining the dots with wire of a certain size.

I have to guarantee:
The volt drop due to impedance won’t affect the operation of the circuit protection
The circuit protection is capable of performing its function
The protection will operate within specified times


Tony the thing to understand is that the NEC is not a design manual. The NEC is a set of Minimum safety standards.
 
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