pv wire and ferrule question

[wrench 87]

I was just looking for opinions on using temco 10 awg pv wire it is stranded but course,should you use a crimp ferrule going in to the dc breaker pros and cons.

 

[timselectric]

It depends on what type of terminal is on the breaker. And how fine the strands are in the conductor.
If the terminal is a clamping type. No ferrule is needed.
If it's a set scew type of terminal. The screw can damage fine strands as it's tightened. And a ferrule will protect the strands from damage.

 

[wrench 87]

it is a clamping type, so no ferrule. thanks again

 

[kolek]

If it's a set scew type of terminal. The screw can damage fine strands as it's tightened. And a ferrule will protect the strands from damage.

@AntronX @rhino @timselectric @Skypower

So anytime you have a set screw type of terminal, you should always use a ferrule? This is completely new information for me and means I need to redo some things in my system. Which brand or type of ferrules do you recommend?

Can you also please address this comment which has been upvoted by a few people claiming that ferrules shouldn't be used on some set screw type terminals? Are these guys wrong, or there's exceptions, or...?

 

[timselectric]

So anytime you have a set screw type of terminal, you should always use a ferrule?

Only if the conductors have fine strands that can be damaged by the set screw. (Twisting against them)

 

[timselectric]

Can you also please address this comment which has been upvoted by a few people claiming that ferrules shouldn't be used on some set screw type terminals? Are these guys wrong, or there's exceptions, or...?

Those are clamp style terminals in the video.

 

[kolek]

Those are clamp style terminals in the video.

I checked Google image search for that keyword and I cannot distinguish "clamp style" from "screw type"
They both have screws?

 

[orion7144]

I checked Google image search for that keyword and I cannot distinguish "clamp style" from "screw type"
They both have screws?

The clamp style lifts a clamp up when tightening whereas the screw type, when you tighten the screw, the screw is pushing on the wire.

 

[kolek]

I recognize this is "clamp style"

https://cdn-reichelt.de/bilder/web/xxl_ws/C160/WAGO_2604-1105.png

I recognize this as screw type:

https://www.camdenboss.com/products/img/CTBP9208_5FL.jpg

Is that correct?

 

[orion7144]

This is a clamp style breaker. The serrated "clamp" tightens the wire when the screw is tightened. The screw type would just be the screw pushing the wire .

 

[kolek]

Oh OK I got it now. Thanks for teaching me that!

 

[AntronX]

screw type, use ferrule on stranded wire only:


screw type with insert for stranded wires, don't use ferrule:


clamp type "wire to board" terminal block, don't use ferrule:

 

[kolek]

Ok that makes it super clear. Thanks much @AntronX

 

[robbob2112]

@AntronX @rhino @timselectric @Skypower

So anytime you have a set screw type of terminal, you should always use a ferrule? This is completely new information for me and means I need to redo some things in my system. Which brand or type of ferrules do you recommend?

Can you also please address this comment which has been upvoted by a few people claiming that ferrules shouldn't be used on some set screw type terminals? Are these guys wrong, or there's exceptions, or...?

see this.

Magic Smoke came out......... ##it happens

diysolarforum.com

 

[timselectric]

I recognize this is "clamp style"

https://cdn-reichelt.de/bilder/web/xxl_ws/C160/WAGO_2604-1105.png

I recognize this as screw type:

https://www.camdenboss.com/products/img/CTBP9208_5FL.jpg

Is that correct?

No, that is lever style.

Yes, on the set screw style.

 

[Skypower]

This is a clamp style breaker(clones?). The serrated "clamp" tightens the wire when the screw is tightened. The screw type would just be the screw pushing the wire .
View attachment 214704

I have this style breaker and it is designed for stranded wires. The serrated surface isn’t raised so it does little to help retain the wire. After tightening 10 AWG thhn, I found that I could wiggle the wire out after using reasonable amount of tightening torque without distorting the case. TEMCo 10 AWG solar wire wasn’t as bad as for poor retaining, probably due to the finer strands. For both types of wire I found out that stripping the wire twice as long as normal and folding it in half then inserting into the terminal keeps it in place. You will also need to follow up on tightening a few times as the strands settle. I’ve had them a couple years now with no problems just be sure that the screws are snugged up! Remember that the screws are live and you don’t get dead.
I tried ferrules in these and they got hot and not sure why but ferrules here are not the answer for me.

 

[kolek]

For both types of wire I found out that stripping the wire twice as long as normal and folding it in half then inserting into the terminal keeps it in place

I like this idea. Makes sense that it would work better. I'm going to try it when I connect to grid using the "clamp type" on my inverter.

 

[robbob2112]

I have this style breaker and it is designed for stranded wires. The serrated surface isn’t raised so it does little to help retain the wire. After tightening 10 AWG thhn, I found that I could wiggle the wire out after using reasonable amount of tightening torque without distorting the case. TEMCo 10 AWG solar wire wasn’t as bad as for poor retaining, probably due to the finer strands. For both types of wire I found out that stripping the wire twice as long as normal and folding it in half then inserting into the terminal keeps it in place. You will also need to follow up on tightening a few times as the strands settle. I’ve had them a couple years now with no problems just be sure that the screws are snugged up! Remember that the screws are live and you don’t get dead.
I tried ferrules in these and they got hot and not sure why but ferrules here are not the answer for me.
View attachment 214733

Ferrules get hot if they are not the right size for the wire and aren't full when crimped. Or if the walls are to thin or to thick. Or if you use the wrong shape crimper. For your picture it would need the 4 sided crimper.


Only needed it the wire is fine stranded. For the solid did you use a torque screwdriver and get it tight enough?


Three squeeks is not the same as a torque wrench of screwdriver

 

[meetyg]

I have this style breaker and it is designed for stranded wires. The serrated surface isn’t raised so it does little to help retain the wire. After tightening 10 AWG thhn, I found that I could wiggle the wire out after using reasonable amount of tightening torque without distorting the case. TEMCo 10 AWG solar wire wasn’t as bad as for poor retaining, probably due to the finer strands. For both types of wire I found out that stripping the wire twice as long as normal and folding it in half then inserting into the terminal keeps it in place. You will also need to follow up on tightening a few times as the strands settle. I’ve had them a couple years now with no problems just be sure that the screws are snugged up! Remember that the screws are live and you don’t get dead.
I tried ferrules in these and they got hot and not sure why but ferrules here are not the answer for me.
View attachment 214733

I have a similar breaker and 10awg PV wire.
Although the strands are pretty thick, I preferred to use ferrules. No problems so far.

 

[timselectric]

For both types of wire I found out that stripping the wire twice as long as normal and folding it in half then inserting into the terminal keeps it in place.

This is the best possible connection for a clamp style terminal.