Circuit breaker problem (Midnite solar breakers in baby box)

Skyko

I am trying to wire up my Magnum 4024M inverter using a Midnite solar baby box and 60 amp breakers (bought off NAWS). I am using Ancor marine tinned wire, 8 gauge, on the 120V AC side and am having an with keeping the hot wires staying in the breaker. Yes, I do have the wires stripped and have placed them correctly in the breaker and have tighten down the screw. There just doesn't seem to be enough bite in the holding mechanism (it has little ridges in the two clamping surfaces). A gentle tug and the wires just pop right out.

Debating what to do here. I know it is bad to solder AC wiring, but perhaps I could create a bit of a bite by partially soldering some of the strands together before inserting them into the breaker?

Anyone else ever have this problem? Solution? I would have preferred a breaker with a screw lug and I could just crimp a terminal on the hot wire and be done...

Photowhit

Re: Circuit breaker problem (Midnite solar breakers in baby box)

Not sure how your using the breakers with the inverter? 4000 watts at 24Volts would require, 4000/24 = 165+ so a 175 amp or perhaps 250 amp breaker.

copper wire requires that you install, tighten then come back in 4 hours (or over night) and retighten. The copper flows and loosens.

I haven't had problems with my breakers, but I only checked them after a couple months, after the 2 tightening's. I should check them after last years hot summer. something to do when I get home.

BB.

Re: Circuit breaker problem (Midnite solar breakers in baby box)

I would call Midnite support.

Something does not sound right.

Double check how you put the wire into the breaker... Some have a little "saddle" that goes over the wire, and the set screw pushes down on the top of the saddle. Sometimes, it is possible to put the wire between the wire and and the set screw--And have a very poor connection (depends on the design of the breaker/connection).

Also, if this marine wire is made from many fine strands--That may be a problem too. Generally, standard breakers are designed for solid or the coarse stranded wire you see for house wiring. Putting very fine wire into the breaker may not work well.

-Bill

Skyko

Re: Circuit breaker problem (Midnite solar breakers in baby box)

It is fairly fine wire. I could crimp the stranded wire to a small section of solid copper wire I guess. I could also try a little solder on the strands but this is probably frowned upon.

The breaker has what is called compression clamps where when you turn the screw it pulls up a plate that sandwiches the wire between that and another plate. Usually those work well with stranded wire but perhaps the large gauge.

Re the breaker size: This is for the AC side. Magnum recommends a 60 amp breaker...actually I think they recommend these Midnite solar breakers.

Photowhit

Re: Circuit breaker problem (Midnite solar breakers in baby box)

Skyko wrote: »

Re the breaker size: This is for the AC side. Magnum recommends a 60 amp breaker...actually I think they recommend these Midnite solar breakers.

I wasn't thinking about the AC side, and even plan on wiring my AC this way at somepoint!

'Coot thanks for cleaning up my faux pas!

Vic

Re: Circuit breaker problem (Midnite solar breakers in baby box)

Skyko,

I, too, have had much trouble with the MN CBI AC breakers ... the wires will often simply fall out, after a period of time, although this issue has been with 30 Amp AC breakers (with a grey plastic body color).

Part of the problem may be with the head of the screw that operates the clamp for the cable, and also, neither the screw, not the wire is visible while one is tightening the screw.

Thread here on the MN Forum:
http://midniteforum.com/index.php?topic=1386.0

I sure hope that CBI (the manufacturer) has changed the design a lot. Have been surprised that these breakers would pass ETL listing tests. Had felt that higher Amp-rated breakers with larger wire would be better.

Do expect that THHN building wire would perform much better than Fine-stranded cable, as the 19-strand THHN should be much more rigid, and therefore resist clamping force reduction as the strands "flow" in time.

Opinions, Vic

boB

Re: Circuit breaker problem (Midnite solar breakers in baby box)

Did you use a torque wrench ?

Also, did you come back after a while and re-torque them ?

Both of these help.

http://www.midnitesolar.com/pdfs/torque_values.pdf

boB

Vic

Re: Circuit breaker problem (Midnite solar breakers in baby box)

Hi boB,

If those questions were for me, YES, always torque (only by feel), and re-torque the next day, and then, if possible torque again in about a week. Then try to check them again in about one year.

In that linked Thread on the MN Forum, there was some discussion regarding a small design change that CBI had made on these AC breakers.

I have had NO problems whatsoever, ever, with any other breakers, busbars, or terminals coming loose, or failing pull tests -- NONE.

In addition, the MN CBI MNEPV DIN-Rail DC PV breakers have not presented ANY problems, at all, whatsoever, and have used many, many of them. The particular DIN AC breakers with the issues had a Phillips-like screw head ... others had believe that this screw head was, the very uncommon Reed & Prince head. This unusual crossed head screw required a huge downward force in order for the screw driver tip to not slip out of the screw's head. This great down force was almost impossible to create with the CBI DIN AC breaker mounted on its DIN rail. So it was really almost impossible to properly torque these screws. Ant the passage that the screwdriver bit needed to pass into to reach the screw was quite small, such that a somewhat larger Phillips bit would not fit into the hole that had the screw at its bottom.

I do love MidNite, and almost all of your products. You guys are tops in my book. This breaker design was NOT MN's.
Sorry to be so strident about this one issue, BUT, had felt that these breakers were almost impossible to torque correctly, due to a design flaw, and that MidNite was an important customer of CBI, so that you folks might have some leverage with CBI to help convince them to redesign this one DIN AC breaker.

FWIW, my Opinions. 73 Vic

inetdog

Re: Circuit breaker problem (Midnite solar breakers in baby box)

Vic wrote: »

The particular DIN AC breakers with the issues had a Phillips-like screw head ... others had believe that this screw head was, the very uncommon Reed & Prince head. This unusual crossed head screw required a huge downward force in order for the screw driver tip to not slip out of the screw's head. This great down force was almost impossible to create with the CBI DIN AC breaker mounted on its DIN rail. So it was really almost impossible to properly torque these screws. Ant the passage that the screwdriver bit needed to pass into to reach the screw was quite small, such that a somewhat larger Phillips bit would not fit into the hole that had the screw at its bottom.

Any chance it was actually the newer (relatively) and better engineered PosiDrive cross slot profile? Those bits are quite readily available to try and cam out much less vigorously than Phillips.
Unfortunately, for optimal performance (maybe even acceptable performance) the two are not really compatible for high torque applications.

CDN_VT

Re: Circuit breaker problem (Midnite solar breakers in baby box)

Yes funky breakers , straighten wire strands , I squeeze with duck bill clamping pliers , use SDG Silicone Dielectric Grease , tighten out of the box / mounting , and then re-tighten before mounting breaker , check after a few days . They are funky , wouldn't pass in real daily installs . they would find a better breaker board supplier, solar has it's quirks .
VT

boB

Re: Circuit breaker problem (Midnite solar breakers in baby box)

Vic, the torque question was for Skyko but you know these basic breakers.

Robin evidently tried to respond but couldn't log on (must have forgotten his password)
but until he presses the "forgot password" button, here's his message.
boB

Bob, I can't sign on. I guess I do not know my username or password and I
did not see a way to ask for them.

You said it correct, but more explanation might help.

Vic understands it quite well. The screw head is indeed Reed and Prince.
This is something that I did not know until I visited the factory in South
Africa. We use slotted screw drivers at MidNite. The head needs to fill up
the hole. Too narrow and it doesn't work worth beans. You MUST go back and
re-torque after an hour. I suspect the breaker was never torqued to 20 inch
pounds in the first place. You need a good screw driver and lots of
pressure. The wires were probably not tight enough. I do not have any
experience with fine strand wire though. Do not add solder. That will only
cold flow more than the copper since it is softer.

CBI makes 25,000 breakers like this every day. We have bought and sold about
2 million of them over the years. They do tighten up just fine, but you need
to work at it until you become familiar with their quirks.

By the way, I have complained about the screw heads for years now. They made
the screws non replaceable. I do not consider that an improvement. People
just get used to these breakers. They are the only thing on the market to do
the job we all need done, so recheck your torque and do not wiggle the wire
after it is finally tight.

Robin

inetdog

Re: Circuit breaker problem (Midnite solar breakers in baby box)

Try Username Robin Gudgel, which was in use back in June of this year.

And the forgotten password link is very obscure. You go to Register and enter the old Username. It will tell you that it is already in use and will then offer you a forgotten password link.

boB

Re: Circuit breaker problem (Midnite solar breakers in baby box)

inetdog wrote: »

Try Username Robin Gudgel, which was in use back in June of this year.

And the forgotten password link is very obscure. You go to Register and enter the old Username. It will tell you that it is already in use and will then offer you a forgotten password link.

Thanks ! I will forward this info off to Robin.

Skyko

Re: Circuit breaker problem (Midnite solar breakers in baby box)

Ok, thanks for the responses. It is at least nice to know others have had some difficulty so I know I am not just crazy.

I do have a nice CNI digital torque wrench I can set for 20 inch pounds. I didn't use it for this because I felt the force I had used with a regular screwdriver was sufficient but I will go back and torque it to exactly 20 inch pounds. I will torque it again after an hour.

when/if it fails, it should be a good test of Magnum's arc fault detection circuitry, so that is a bonus! (always looking on the bright side)

vtmaps

Re: Circuit breaker problem (Midnite solar breakers in baby box)

Skyko wrote: »

but I will go back and torque it to exactly 20 inch pounds. I will torque it again after an hour.

You may still have problems if you are using fine strand wire. I don't think the breakers are listed for fine strand wire... but there is a way: ferrules. Good selection to explore and research here: http://www.ferrulesdirect.com/electrical/WIRE_FERRULES.htm

--vtMaps

Skyko

Re: Circuit breaker problem (Midnite solar breakers in baby box)

vtmaps wrote: »

You may still have problems if you are using fine strand wire. I don't think the breakers are listed for fine strand wire... but there is a way: ferrules. Good selection to explore and research here: http://www.ferrulesdirect.com/electrical/WIRE_FERRULES.htm

--vtMaps

I thought about ferrules but two considerations: 1) The ferrules for 8 gauge wire might have too large a diameter to fit in the breaker slot and 2) The ferrule material might not get a bite on the breaker clamping system (are these copper ferrules?)

It also becomes space constrained in such a tiny baby box to put much on the end of the wire, although the ferrules seem not large (but you would need to add heat shrink insulation which would make it hard to bend the wire).

I am going to do a little testing on a spare breaker with the same stranded wire, torque to 20 inch pounds, wait an hour torque again, then see about how much vibration and pull force is needed to cause the wire to come out. I am also going to try solid copper wire as I could crimp a small section of this onto the stranded wire (I use a hydraulic crimper). If the solid copper wire has a better bite, then that might be the way to go.

If I were designing these breakers, I think I would have allowed a space beyond the compression clamp for 1/4" of wire. That way when the clamp squeezes the wire, the end of the strands would fan out and remain un-squeezed, creating a sort of stopper. Other option would be to increase the size/sharpness of the ridges in the two clamping surfaces such that there is a greater PSI force on the wire from the clamping.

Cariboocoot

Re: Circuit breaker problem (Midnite solar breakers in baby box)

If only the world had sense enough to adopt the Canadian Robinson square drive screws a lot of trouble could be saved.

BB.

Re: Circuit breaker problem (Midnite solar breakers in baby box)

boB (and Robin),

I have sent a password reset to Robin. If he still has problems, just send me a PM or email and I will give him a new password.

Take care,
-Bill

Vic

Re: Circuit breaker problem (Midnite solar breakers in baby box)

Hi boB, Robin, and all.

Thank you very much for the replies.

This is just another of the many examples of the great Service and Support form MidNite Solar!

A customer posts an issue when using a MidNits supplied product, and in less than four hours there is a reply from a MidNite Principal & Founding Engineer. Shortly thereafter, another reply from the other MidNite Founding Principal & Engineer!

This is truly very impressive. Know of no other company (of any size) in any field, where one would find this on a regular basis.

Thanks boB, Robin, and all who stepped in to help. There are many examples of this happening on the MidNite Fourm, here, and probably elsewhere where MidNite Solar Engineering, Technical Support and other employees of MidNite step up to help customers, in very public places.

Thanks MidNite! Sorry to gush a bit, but no one else does this (in my experience). Vic

boB

Re: Circuit breaker problem (Midnite solar breakers in baby box)

Thanks Vic and BB et. al. (whoever "AL" is ?)

We just enjoy what we do I guess. Not just a 9:00 to 5:00 gig ya know !

One day we're gonna have to have us one big party with all the forum folks
and dance around the PV pole ! (or something like that)

boB

Skyko

Re: Circuit breaker problem (Midnite solar breakers in baby box)

I wasn't being down on Midnite btw. I know they are not actually the ones making the circuit breakers.

I have just purchased a Midnite Classic 150 and am anxious to install it when I get this Magnum inverter finished (I don't have the panels mounted on the RV roof yet so the solar is taking a backseat).

I did torque the screws now to 20 inch pounds (not easy to do with just 2 hands). I torqued them again after a couple of hours. They seem to be holding somewhat better now but I will keep an eye on them and recheck in a few weeks.

CDN_VT

Re: Circuit breaker problem (Midnite solar breakers in baby box)

Attachment not found.Attachment not found.Attachment not found.Im using PosiDrive bits for these breakers .( Phillips Reed & Prince they are not, I have most of the bits made)
Posi-#2 fits the best .for myself. I'll try to take a picture of my setup on torquing these.
Here is some reading on Bits & drivers . Robertson & square are not the same Coot , Ya know when the screw just won't stay on the bit ,I buy square drivers in USA for them junkie square screws . Robertson Bit (driver) & screws rule for construction !! Robertson driver with a square screws cause me grief, I now take my R-bits in when i buy boxes of screws (50# ) .. Less grief , i craiglist-ed the square drive screws out..

http://en.wikipedia.org/wiki/List_of_screw_drives#Pozidriv

For a good list of getting the correct screw ^^^^^ read above

As for the world of metric , 20 pounds inch in torque (Not Force ) would be useless for a KG/CM or however your standard is set.
I have a great FREE convert program for all ISO standards , I'd e-mail PM or Mods figure it .. 548KB , Im 17 stone weight :-) ..
20 LBs/Inch or 20 inch pounds is 2.25 Nm Newton Meter.

VT

HTH's

Cariboocoot

Re: Circuit breaker problem (Midnite solar breakers in baby box)

CDN_VT wrote: »

Robertson & square are not the same Coot

Yes; the Robertson ones work.
Never liked the Phillips system at all, and Torx is little more than fancy-dress Allen.
Can't remember the last time I used a slot-head screw.

Sometimes the "better ideas" aren't.