Behavior of Joule Heating in few contact points terminals and arcing

[ptonsparky]

My bad, but hopefully my point is not lost because of it Hal



I've found the actual bit matters, most breakers and devices are manufactured w/screws that will accept multiple styles





well first the listing/rating of any connector should be addressed....

2ndly, the 'pretwist vs. no pretwist ' debate boils down to the area of contact w/in the wirenut 'spring'.....anecdotally, i find that cutting the very ends the same allows for more contact of all wires introduced.

Just what their failure rate is juxtaposed to other connectables (wago, screw block, backstab) would be an appreciable study......
http://www.ieee-holm.org/h2004/h2004antler.pdf

3rd, there are many tools on the market exclusively for wire nuts>

thus a torque spec must exist....






Addressing specifics is what engineers do , usually to extents most would not pursue because they've the patience where most do not Hal.

~RJ~

The contents of the four square looks like a combination of cu to al wire. Not a fair test to most wire connectors, with or without the unevenly cut conductors.

 

[romex jockey]

The contents of the four square looks like a combination of cu to al wire. Not a fair test to most wire connectors, with or without the unevenly cut conductors.

Good catch, i had not noted that Pton

and yet another variable appears .....

AL & CU splicing methods, we all know what we'd use on the bigger stuff

&&&&

&&&&

but what for smaller?

&&&

&&&

~RJ~

 

[tersh]

&&&

This is the best, the 3 AWG 10 will actually be pressed down just like in breakers or chair lugs. What exact brand is it??

 

[romex jockey]

Iirc>>>>
https://www.homedepot.com/p/AlumiConn-3-Port-Al-Cu-Wire-Connectors-10-Pack-95110/202889892

so now i'm wondering if different material(s), such as CU / AL , need different torque specs....???

~RJ~

 

[tersh]

Iirc>>>>
https://www.homedepot.com/p/AlumiConn-3-Port-Al-Cu-Wire-Connectors-10-Pack-95110/202889892

so now i'm wondering if different material(s), such as CU / AL , need different torque specs....???

~RJ~

Wow. It's perfect. Also available at amazon. I plan to get this torque screwdriver too along with it.

https://www.amazon.com/gp/product/B00VPPJWLW/ref=ox_sc_act_title_2?smid=ATVPDKIKX0DER&psc=1

But it's only rated at 10 to 50 lb-in.

The Siemens load center main breaker needs torque of 55 lb-in. What would happen if you only use 50 lb-in for it and there is a missing 5 lb-in?

How do you supply the additional 5 lb-in? I can't find a quality torque screwdriver with 10 to 80 lb-in rating for example.

I'd let the electrician use them. You see. In our place, our electricians only have money for 3 days or a week. Then they are broke. This is why they never have any tools.

 

[ptonsparky]

Wow. It's perfect. Also available at amazon. I plan to get this torque screwdriver too along with it.

https://www.amazon.com/gp/product/B00VPPJWLW/ref=ox_sc_act_title_2?smid=ATVPDKIKX0DER&psc=1

But it's only rated at 10 to 50 lb-in.

The Siemens load center main breaker needs torque of 55 lb-in. What would happen if you only use 50 lb-in for it and there is a missing 5 lb-in? An AB relay said a Max of 4.5 InLb. What if I used 4.6?

How do you supply the additional 5 lb-in? I can't find a quality torque screwdriver with 10 to 80 lb-in rating for example. How tough are you?

I'd let the electrician use them. You see. In our place, our electricians only have money for 3 days or a week. Then they are broke. This is why they never have any tools. Your place is broken. I don't have a solution other than to educate, train and pay them more. You can't expect too much if you are always looking for the lowest priced.

Notes above.

 

[tersh]

Notes above.

How hard is it to turn 50 lb-in? The main breaker is rated at 55 lb-in. The electrician doesn't want to use too much force to avoid destroying the lugs, so he just turned it until it's tight and stopped.

Perfect tool would be at least a 10-60 lb-in. But most torque screwdriver is only rated from 10-50 lb-in.

 

[peter d]

You're really trying our patience with your inept questions and it's getting ridiculous.

:thumbsup:

I can't believe the bandwith wasted with this guy already. :slaphead:

 

[Russs57]

I’ll offer this. As a plumber we installed cast iron pipe with “no-hub” clamps. They have 5/16” hex head screws. You use a T handle preset torque wrench set for 60 in-LBs.

I could do 60 in-LBs with a screwdriver but you need something you can get two hands on.

 

[LarryFine]

The electrician can't get the wire twisted inside the red wire nut. When he removed it. The wires inside are all straight like original. No sign of twisting. This only works for smaller wires? And it's normal for the conductors to be straight inside with the springs only compressing it at all sides?

Twisting solid wires does not increase the contact area. It is normal for the springs to provide all of the contact compression.

Contractors were used to just splicing even AWG 4 without using any connectors. They installed one in the other building where AWG 4 were spliced using just electrical tapes.

That's crazy. I might consider the big blue (or gray) wirenuts, but split bolts or other mechanical devices would be better.

 

[LarryFine]

I've used these to make electrical connections for accessories on my motorcycles. Easy connections, high current capacity, and self-insulating. Can't beat that.

 

[tersh]

Twisting solid wires does not increase the contact area. It is normal for the springs to provide all of the contact compression.


That's crazy. I might consider the big blue (or gray) wirenuts, but split bolts or other mechanical devices would be better.

So the following is correct?

Correct in the sense that the springs just pressed on the half inch or so of the wire ends without really twisting them? This is robust enough for 20 years installation period?

The other red screw nuts were all removed from present installation pending analysis. We still have a couple connected and we were nervous whether to totally remove them and await the violet Alumiconn we ordered.

The thing is with three 5.5mm^2 (our size) instead of 5.2mm^2 (your AWG 10). It may cross the threshold where the added size would make it more stiff and less space for it to work. Remember wire nut were rated up to American AWG 10 only or 5.2mm^2. It's not yet tried on 5.5mm^2 until now.

 

[hbiss]

My bad, but hopefully my point is not lost because of it Hal

Addressing specifics is what engineers do , usually to extents most would not pursue because they've the patience where most do not Hal.

I understand and see that you enjoy talking about these things. But come on, is this really the place for this guy? There are differences in engineers, those related to the industry are welcome to ask questions here. Then there are others like this one who have no knowledge of this trade and are no better than DIYs.

This is not my board, my name is not Mike nor am I a moderator. But if it were up to me Tersh would be long gone, probably after his first post. Now it's turned into a can of worms with over 400 posts. This is a professional forum, and his DIY questions in my opinion don't belong here.

-Hal

 

[kwired]

I've found the actual bit matters, most breakers and devices are manufactured w/screws that will accept multiple styles

20 in-lb is 20 in-lb regardless of what type of bit is used to drive it. Certain designs may make a better grip than others and make it easier to achieve higher torque levels.

Let's create a teardown of it:

Only the front are compressed. Is this normal?

Please show me images like it with different sizes of wires and wire nuts. I'd like to see how the insides actually look like.

How hard is it to turn 50 lb-in? The main breaker is rated at 55 lb-in. The electrician doesn't want to use too much force to avoid destroying the lugs, so he just turned it until it's tight and stopped.

Perfect tool would be at least a 10-60 lb-in. But most torque screwdriver is only rated from 10-50 lb-in.

Whether twisted or not spring still contacts outer surfaces and compresses inner surfaces together. Amount of twist achieved will affect amount of surface area involved in each conductor. Higher the current being carried the more important this may possibly be.

Conductors that are twisted but do not have a mechanical device used to help assure connection are not acceptable at all for power carrying conductors, you may get by for a long time with this on control/signaling conductors that carry low energy.

Many years ago it was more common to not use a mechanical device, but they twisted conductors together then still secured them with solder.

To twist or not to twist with "wire nuts" has been debated to death on this site. Neither method is unacceptable per NEC or the instructions that are a part of the listing of nearly every connector of this type out there.

 

[tersh]

I understand and see that you enjoy talking about these things. But come on, is this really the place for this guy? There are differences in engineers, those related to the industry are welcome to ask questions here. Then there are others like this one who have no knowledge of this trade and are no better than DIYs.

This is not my board, my name is not Mike nor am I a moderator. But if it were up to me Tersh would be long gone, probably after his first post. Now it's turned into a can of worms with over 400 posts. This is a professional forum, and his DIY questions in my opinion don't belong here.

-Hal

Don't worry. I will leave tomorrow as I have nearly acquired all information I need. I am allowered here because I am a former engineer, active 25 years ago and just reviewing the trade now. If I were not an engineer. I was long gone. They allow engineers to participate as long as they don't do the work themselves. I qualify because I have an electrician.

But I agree with you that this forum should only be for experts like you to discuss more complicated problems. So I will leave soon and no longer ask questions.

Thank you so much for all those who have helped and had the patience. Without your help. I couldn't have created the Philippines first 100% full house GFCI protection home using US technology. So no matter how nasty some is. I accept it because in electricity, knowledge is power and more important than ego.

 

[LarryFine]

So the following is correct?

Correct in the sense that the springs just pressed on the half inch or so of the wire ends without really twisting them? This is robust enough for 20 years installation period?

Yes. If the firm contact area is at lease equivalent to the area of the conductors, there should be no additional heat created.

 

[mbrooke]

I understand and see that you enjoy talking about these things. But come on, is this really the place for this guy? There are differences in engineers, those related to the industry are welcome to ask questions here. Then there are others like this one who have no knowledge of this trade and are no better than DIYs.

This is not my board, my name is not Mike nor am I a moderator. But if it were up to me Tersh would be long gone, probably after his first post. Now it's turned into a can of worms with over 400 posts. This is a professional forum, and his DIY questions in my opinion don't belong here.

-Hal

His level of knowledge comprehension stretch well beyond DIY as well as his ability to take it all in. He is asking all the right questions, and some of them are very in depth that have even us looking back on what we've learned. He is contained to a few threads and not hopping about. Over all I like his questions as they are making me think. Finally consider that he is from a part of the world where 99.999% of the electricians and electrical engineers do not even know what a ground wire does.

 

[romex jockey]

While the study of a fundamental may seem a lame exercise, it is the number one issue in our trade, debatably the number one incendairy stat pursuant to fire, as well as the leading maintenance demon.

It's also been the focus of phd level EE's before the IEEE, CMP ,CSPC, NFPA, along with an entire cast of professionals

Objectively, this makes joule effect the most important issue of our trades time

Further, the electrical marketing establishment has been in a decade long worldwide patent battle , because they fear point of use thermal detection will oust their billion dollar biz

A battle that would not even exist....if you 'pro's understood the fundamentals of our trade in the first place....:rant:


~RJ~

 

[peter d]

I understand and see that you enjoy talking about these things. But come on, is this really the place for this guy? There are differences in engineers, those related to the industry are welcome to ask questions here. Then there are others like this one who have no knowledge of this trade and are no better than DIYs.

This is not my board, my name is not Mike nor am I a moderator. But if it were up to me Tersh would be long gone, probably after his first post. Now it's turned into a can of worms with over 400 posts. This is a professional forum, and his DIY questions in my opinion don't belong here.

-Hal

:thumbsup::happyyes::happyyes::happyyes:

 

[kwired]

I understand and see that you enjoy talking about these things. But come on, is this really the place for this guy? There are differences in engineers, those related to the industry are welcome to ask questions here. Then there are others like this one who have no knowledge of this trade and are no better than DIYs.

This is not my board, my name is not Mike nor am I a moderator. But if it were up to me Tersh would be long gone, probably after his first post. Now it's turned into a can of worms with over 400 posts. This is a professional forum, and his DIY questions in my opinion don't belong here.

-Hal

I have mixed feelings on whether this content should be allowed. If it were a US installation, I think it doesn't belong at all. The fact it is somewhere else on the planet and to see the stuff that is pretty much standard installation there that he has posted, is kind of amusing and comes with completely different set of rules and potential legal consequences compared to making comments and giving advice to a DIY person in this country.