Breaker install

[Bluedog225]

Good evening.

I’m trying out various solar disconnects.

I’d appreciate some help wiring these din rail mounted breakers correctly.

I see that they are meant to be installed a particular way. As in, do not reverse feed.

I was planning on using them as a solar panel disconnect and I don’t understand how I would wire them.

For example, if I put them on the positive line, do I feed in through the positive side and out through the negative side?

Put another way. I don’t understand the positive and negative symbols on this. Is it intended to indicate direction of current flow?

Many thanks.

 

[FilterGuy]

I would not use these as a pv disconnect. There is no way to wire them that does not have the potential of a reverse current flow.

 

[rhino]

What @FilterGuy is saying succinctly is there has been discussion on here before about using those breakers even though that is what Midnite uses in their PV combiner boxes and what is sold for them.. there was someone from here who even had a conversation with someone at Midnite about it not handling the reverse current (the thread is on here somewhere). At the array some people use the IMO disconnects but that isn't always an option on interior close to the AIO/SCC since it is a plastic enclosure.

I personally still have those Midnite breakers installed on my older arrays at the array in combiner box as a means of disconnect.

 

[rhino]

I used these on my new array and disconnect both the positive and negative: https://www.amazon.com/dp/B012MWNSXE

 

[Hardergamer1]

Like you said, It would mean postive out of the panels into the postive side of the breaker, and out of the breaker into the postive on the contoller, and don't fues the negtive side but put your disconnects there.

Sorry I see now you said for disconects, not fueses. To mutch Xmas shandy.

 

[Hardergamer1]

I used these on my new array and disconnect both the positive and negative: https://www.amazon.com/dp/B012MWNSXE

I just I use them too
And just add, as I don't trust my cheaper MrPower CC I use them on both in and out of my CC too.

 

[12vDC]

MIDNITE THREAD I believe this is the thread mentioned above.

I have the MNEDC15 for my single 70Voc panel. I remember I went through the trouble of marking each end of the breaker with "PV" and "Load" so I must have looked up how to wire it. It can be confusing.

Ive been using the breaker to disconnect the system frequently in the last several weeks while I updated components of my bank. I have not had any ill effects so far in the 1.5years in use. Hopefully I wired it correctly?

Maybe someone could comment on the side-effects of getting the polarity incorrect?

 

[Bluedog225]

I will review the Midnite thread.

Absent a better understanding, it sounds like these breakers are ok as breakers. But may not be good disconnects.

I’ll use the old disco until I understand better.

Thanks all!

 

[Hedges]

I think they could be used safely for 3+ strings if you slipped a wire through the handles to gang them.
A shorted string getting backfed would trip its breaker. Even though that pole couldn't interrupt reverse current, it would trip the other poles which would interrupt their forward current.

 

[400bird]

.

 

[hwy17]

Positive: Solar ---> CC

Negatuve: CC ---> Solar

This is not an educated opinion about those breakers, just my guess at orientation based on the arrow on the breaker and my knowledge of polarity.

*During regular production flow, and not reverse current flow. It strikes me know that reverse current might actually be the thing you want them to break. Idk.

 

[OzSolar]

We use a lot of this style. Both 30 and 60 amp. Very overbuilt. Rated to 250 vdc but I've tested them to 500v+ on my personal system and no worries. Pick one up and you'll see what I mean.

Siemens General Duty 30 Amp 2-Pole 2-Wire 240-Volt Non-Fusible Indoor Safety Switch GNF221A - The Home Depot

General Duty Safety Switches are intended for applications where reliable performance and continuity of service are needed. But where duty requirements are not severe and usual service conditions prevail.

www.homedepot.com

 

[Bluedog225]

That big honkin thing has a lot of appeal. Thanks!

 

[OzSolar]

That big honkin thing has a lot of appeal. Thanks!

You're welcome! You really should get one if only so you can learn the secret electrician handshake. There's a very specific of way of squeezing the box sides while wiggling the door to remove the door to allow for much easier wiring. Almost like the horseshoe thing at Cracker Barrel.