MNEDC Breaker stuff

[Vic]

OK,  am on a breaker tangent.

In the past,  have been involved in a discussion here,  which I cannot now find,  that involved the venerable Trace/Xantrex 1-inch breakers.  These were the AirPax/Carlingswitch CD Series DC breakers.

I still like this breaker,  and they still can be found in distribution ... know that they can be a bit more costly etc.

Regarding the CF series, (an extension/improvement on the CD)  they have a major benefit of having a front-facing screw lug for the wire,  as opposed to theCD or  MN/CBI style of rear studs.  The studs require that the installer crimp a lug on the wire,  and generally require a somewhat longer service loop  for accessibility,  both of which are a disadvantage.  The CF breakers also have an insulating barrier on one side of the lug to protect adjacent circuits.

Since MN is a large customer of CBI,  I would propose that MN discuss having such a feature available in the MNEDC style 3/4" breaker.  Would simplify installation and make it cleaner IMHO.

The world is just full of great ideas,  no?  Thanks,  Vic

[Robin]

Box lugs on breakers are not always such a good idea. The larger the wire, the more we all tend to use very fine stranded wire. The connections on a compression box lug can work its way loose. This is called cold flowing. We torque all our connections at MidNite and then go back and do it again an hour later.
A crimped terminal secured by a nut and lock washer is safer.
The CF/CD series was designed into the Trace Engineering breaker boxes back in the early 1990's. Xantrex still has them designed into their stuff. That is probably because they bought Trace and just copied what Trace did. The fact is that when we designed those breakers into the products back then, there were no other choices. The CD series is a very old design, It has plastic under compression. That is a no no these days. You can hardly tighten the studs down without moving the internal guts of the breaker. When I started OutBack, I researched breakers once again and found the Carling and CBI breakers. I was able to convince both companies to go back to UL and get the breakers re-rated for 125VDC. They were only rated for 80 at the time. We have since had them tested and listed to 150, 300 and now 600VDC. The MNEDC and the MNEPV breakers are by far a superior breaker at much less cost and are smaller. I receive a lot of calls from customers that purchased Xantrex distribution panels. They are always asking for those old style CD breakers in a value that is not stocked by anyone. MidNite only has the 125 amp in that style. After telling people we can't help them for a couple of years, I finally got the idea to create a plastic adapter that would allow our MNEDC (3/4" wide) breakers to be used in a 1" wide slot. We will probably never sell enough of these adapters to even pay for the tooling, but at least I don't have to tell those customers that we can't help them.

[Vic]

Hi Robin,

Just saw this post.  Thanks for the detaialed reply,  and history.

Thanks for your work on the Carling and CBI Breakers.

At the time that I was configuring my latest install of venerable SW+ 5548s with the X DCCB-Ls,  decided to use the old one-inch Airpax breakers,  as I did not know of the 1"--3/4" adapter that MN offers.

I am very impressed at how aggressive you folks are in looking foreward at what the market will demand in the future and getting new,  innovative products available BEFORE the demand appears.  Many other companies seem to be way behind the curve on the BOS components getting into production/distribution.

Congratulations!,  And do appreciate that your solutions are almost always very affordable.

Thanks again,  Vic

[Vic]

And,  not to beat this subject to death ...

Here is a pic of the CF breaker:Oh,  images too large,  and have no way of resizing it/them ...

The Compression Lug is no longer compressing the case of the breaker.  I do not use fine-stranded wire on these,  usually just THHN.

Thanks,  Vic

[Robin]

The older CD and CF series of breakers do actually have the plastic case under compression. It is the nut that holds the stud tight. Hmmmm you said box lug......I don't have one of those handy, but suffice it to say UL would never allow that type of design anymore.
As far as fine stranded wire in a box lug. Go for it. I do not subscribe to the theory that this is a bad thing. We always go back and re-torque all wires after they have set for an hour or so. This practice insures the copper doesn't cold flow and loosen up. Once in a while we will get another half turn with the torque screw driver after it has already been torqued.