Burnt up junction box

[John Frum]

Why do you think Wago lever nuts are not made for ferrules?
Do you have a citation?

I found this.
At least on the other side of the pond Wago lever nuts + ferrules is a supported combination.

 

[BiduleOhm]

The official doc says it is compatible with stranded and solid wires, and never says you need to add ferrules: https://docs.rs-online.com/6f77/0900766b814ed606.pdf

Also, as @Mattb4 discovered using a ferrule increase the size which makes your wire fall outside of the wago' size range if used with the largest accepted size wire. On top of that the ferrule length probably doesn't match the recommended stripping length, which is one of the most important things you must follow if you don't want problems.

Finally, adding a ferrule adds a contact interface (wire/ferrule + ferrule/wago, instead of just wire/wago) which adds resistance.

Don't get me wrong, I love ferrules and I use them when it's necessary (typically for screw type terminals with stranded wire), but here it has a lot of problems without any advantages.

 

[JAS]

Thanks for all the feedback everyone!

Good tips on watching that the Wago doesn't clamp down on the insulation.

To answer a few questions:

Hard to tell from the Amazon listing or what's left of my Wago, what the amp rating is. But, since the entire assembly is rated at 30A, I would hope they'd use the proper Wago to go with it. (Even if it was only 20A, I was still under that)

The assembly came with 10AWG stranded wire with the Wago already attached. I removed it and installed the ferrule (on the stranded wire from the assembly, not the solid wire). In hindsight, I probably should have left well enough alone.

My AIO is the MPP Solar LV1012-MS. The documentation does not specify one way or another whether to use stranded or solid for the PV connection. However, the connections are the same style as the AC connections (which is fine with Romex)

In my research, Romex was fine for using in a DC application (as long as it was the proper gauge)

My only other potential thought is that I actually used UF 10/2 wire (not regular romex). My electrician told me that since UF is hard to strip (without nicking the copper), he actually uses a butter knife. I guess potentially, I had nicked the UF wire when I stripped it and that caused the problem

 

[BiduleOhm]

Hard to tell from the Amazon listing or what's left of my Wago, what the amp rating is. But, since the entire assembly is rated at 30A, I would hope they'd use the proper Wago to go with it. (Even if it was only 20A, I was still under that)

The official doc says it's 20 A UL rated and 32 A ENEC rated so no worries here.

My AIO is the MPP Solar LV1012-MS. The documentation does not specify one way or another whether to use stranded or solid for the PV connection. However, the connections are the same style as the AC connections (which is fine with Romex)

In my research, Romex was fine for using in a DC application (as long as it was the proper gauge)

My only other potential thought is that I actually used UF 10/2 wire (not regular romex). My electrician told me that since UF is hard to strip (without nicking the copper), he actually uses a butter knife. I guess potentially, I had nicked the UF wire when I stripped it and that caused the problem

I confirm you can use solid or stranded, it doesn't matter; as long as you terminate it properly to have a good connection of course.

 

[John Frum]

The official doc says it is compatible with stranded and solid wires, and never says you need to add ferrules: https://docs.rs-online.com/6f77/0900766b814ed606.pdf

Also, as @Mattb4 discovered using a ferrule increase the size which makes your wire fall outside of the wago' size range if used with the largest accepted size wire.

Agree, from personal experience 10 awg with ferrule will fit in 221-61x lever nuts but 12 awg with ferrule will not fit in 221-41x lever nuts.

On top of that the ferrule length probably doesn't match the recommended stripping length, which is one of the most important things you must follow if you don't want problems.

Ferrules come in different lengths.
All but one type of ferrules I use are length appropriate for use with the 221 series lever nuts.

Finally, adding a ferrule adds a contact interface (wire/ferrule + ferrule/wago, instead of just wire/wago) which adds resistance.

Agreed, many ferrules recommend to de-rate wire with 90C or greater insulation to 75C when using a ferrule.

Don't get me wrong, I love ferrules and I use them when it's necessary (typically for screw type terminals with stranded wire), but here it has a lot of problems without any advantages.

None of what you said indicates Wago lever nuts are not made for ferrules.
As shown in the video I linked in a previous post indicating Wago supports the use of ferrules with lever nuts.

But now we have an instance in the real world were ferrules may have been the cause of melted junction box.

 

[Supervstech]

Why do you think Wago lever nuts are not made for ferrules?
Do you have a citation?

Wago lever nuts are designed for solid or stranded conductors.
Adding a ferrule is ok on tiny loads, but the wago lever action doesnt have sufficient force to make good contact with a ferrule covered conductor.
There is no reason to use a ferrule with them because the design incorporates area for the stranded wiring.

 

[BiduleOhm]

None of what you said indicates Wago lever nuts are not made for ferrules.

The recommended usage as per the manufacturer's instructions is without ferrules which implies they are either a less good solution or a bad one.

As shown in the video I linked in a previous post Wago supports the use of ferrules with lever nuts.

I can't watch the video right now but I will as soon as I can. However I can already see the video isn't from Wago but from a random channel so unless they quote a document from Wago it's not worth anything.

Wago lever nuts are designed for solid or stranded conductors.
Adding a ferrule is ok on tiny loads, but the wago lever action doesnt have sufficient force to make good contact with a ferrule covered conductor.
There is no reason to use a ferrule with them because the design incorporates area for the stranded wiring.

Thanks, basically exactly what I'm trying to say but much better/shorter phrased than I did.

 

[John Frum]

I can't watch the video right now but I will as soon as I can. However I can already see the video isn't from Wago but from a random channel so unless they quote a document from Wago it's not worth anything.

The claim to have checked with Wago.

 

[John Frum]

Wago lever nuts are designed for solid or stranded conductors.

Agree.

Adding a ferrule is ok on tiny loads, but the wago lever action doesnt have sufficient force to make good contact with a ferrule covered conductor.

Really, what amount of force is required?
How much force does a Wago levernut apply?

There is no reason to use a ferrule with them because the design incorporates area for the stranded wiring.

Agree.

 

[Mattb4]

...

None of what you said indicates Wago lever nuts are not made for ferrules.
As shown in the video I linked in a previous post indicating Wago supports the use of ferrules with lever nuts.

But now we have an instance in the real world were ferrules may have been the cause of melted junction box.

I watched the part of video linked in your post. Sorry but I do not accept what the two people in the video suggested to combine two wire into a ferrule to insert into a Wago in order to not have to buy a multiconnection one.

It is interesting how many failures occur around simple connection issues. Even manufacturers of devices sometimes mess up at it.

 

[John Frum]

I watched the part of video linked in your post. Sorry but I do not accept what the two people in the video suggested to combine two wire into a ferrule to insert into a Wago in order to not have to buy a multiconnection one.

It is interesting how many failures occur around simple connection issues. Even manufacturers of devices sometimes mess up at it.

Your opinion is noted but whether you accept it or not is beside the point.

The presenters in the video claim that according to Wago its a supported configuration.

I would also avoid doing 2 wires to 1 ferrule into a levernut.

 

[Mattb4]

Your opinion is noted but whether you accept it or not is beside the point.

The presenters in the video claim that according to Wago its a supported configuration.

I would also avoid doing 2 wires to 1 ferrule into a levernut.

Actually my acceptance of an idea is the point. There is no shortage of claims. Wading through them requires critical thinking skills.

 

[OzSolar]

Adding a ferrule certainly violates the products listing and it might even be an NEC violation, regardless if you think you're doing a good thing or not. Very similar to pre-twisting wires before using wire nuts.

I attended CEU class given by an engineer from the IDEAL factory. He pointed out that since it's not in thier instructions that you are violating thier UL listing plus plus pre-twisting wires can actually damage them. (oh boy here we go...)

If the Wago instructions don't call out for a ferrule you can't add one in the field.

 

[John Frum]

Agree, from personal experience 10 awg with ferrule will fit in 221-61x lever nuts but 12 awg with ferrule will not fit in 221-41x lever nuts.

Correction.
10 awg with ferrule does not fit in a 221-613.
12 awg with ferrule does fit in a 221-613.
12 awg with ferrule does not fit in a 221-413.

@JAS are you sure the wire you used was 10 awg?

 

[OzSolar]

My only other potential thought is that I actually used UF 10/2 wire (not regular romex). My electrician told me that since UF is hard to strip (without nicking the copper), he actually uses a butter knife. I guess potentially, I had nicked the UF wire when I stripped it and that caused the problem

Are you sure you're using the Wago that's rated to accept up to #10? EG: 221-612 (10awg to 20awg) will vs. 221-412 (12awg to 24 awg). Their part numbers are maddingly similar and if your wire is perfectly straight you can get a #10 into a 412 however the lever won't close with a snap, you have to force it down.

 

[JAS]

The Amazon listing says the assembly is made with 10AWG and the wires looked like 10AWG to me... And the Wago's came with the assembly. So I would assume they were the 10AWG ones...

However, that brings up the point of "stuffing" a 10AWG Wire with a ferrule into the Wago designed for 10AWG max.... It's been a while, so I don't remember, but it's likely I "forced" that ferrule into the Wago

 

[John Frum]

The Amazon listing says the assembly is made with 10AWG and the wires looked like 10AWG to me... And the Wago's came with the assembly. So I would assume they were the 10AWG ones...

However, that brings up the point of "stuffing" a 10AWG Wire with a ferrule into the Wago designed for 10AWG max.... It's been a while, so I don't remember, but it's likely I "forced" that ferrule into the Wago

I Just tried it again.
10 awg with ferrule into Wago 221-613.
I was able to get the ferrule into the levernut.
It bottomed out on the insulating boot so that the conductor barely made contact with the busbar.
I could close the lever but the resulting connection didn't pass the pull test.
It required very little effort to pull the wire out of the levernut.
I think we have a plausible scenario.

 

[OzSolar]

I could close the lever but the resulting connection didn't pass the pull test.
It required very little effort to pull the wire out of the levernut.
I think we have a plausible scenario.

Nice work. Did the lever snap closed or did you have to push it a down a bit?

 

[JAS]

I Just tried it again.
10 awg with ferrule into Wago 221-613.
I was able to get the ferrule in into the levernut.
It bottomed out on the insulating boot so that the conductor barely made contact with the busbar.
I could close the lever but the resulting connection didn't pass the pull test.
It required very little effort to pull the wire out of the levernut.
I think we have a plausible scenario.

John,

Thanks for testing this! Unfortunately, I have to buy another assembly as too much of the wire was burnt. But, this time I'll leave it as designed and leave the cover off on the first sunny day that I can watch it for a few hours. I just ordered a temperature gun so will use that to monitor the connection.

Thanks everyone!

 

[John Frum]

Nice work. Did the lever snap closed or did you have to push it a down a bit?

I do not hear a snap with 10 awg and ferrule.
I do hear a snap with un-ferruled 10 awg stranded.