SPD wiring...

[cdsolar]

In this post:

Correct wiring for Solar Panel SPD

Which of these two wiring diagram is the correct method of installing a DC SPD for Solar Panels? Please give your reason. Assume that the above listed components are inside a single box. Thanks Dan

diysolarforum.com

Two options are presented for wiring the SPD. Regardless of the option chosen, what is the preferred way to do the physical wiring? As the SPD is wired in parallel, I see several options to avoid double tapping the breaker:

1. Tap splice (This seems cheap)
2. Double lug
3. Another busbar (May not be possible in a given enclosure)
4. Pigtail

For sake of argument, let's say we are dealing with 10 AWG and a 20A breaker.

Any thoughts?

 

[timselectric]

If the breaker lug is rated for multiple conductors. That's the easiest option.
If not, a splice, tap, pigtail, or whatever is fine.

 

[solarhombre]

In this post:

Correct wiring for Solar Panel SPD

Which of these two wiring diagram is the correct method of installing a DC SPD for Solar Panels? Please give your reason. Assume that the above listed components are inside a single box. Thanks Dan

diysolarforum.com

Two options are presented for wiring the SPD. Regardless of the option chosen, what is the preferred way to do the physical wiring? As the SPD is wired in parallel, I see several options to avoid double tapping the breaker:

1. Tap splice (This seems cheap)
2. Double lug
3. Another busbar (May not be possible in a given enclosure)
4. Pigtail

For sake of argument, let's say we are dealing with 10 AWG and a 20A breaker.

Any thoughts?

Trying to save space in the box, I was planning on using twin ferrules like https://a.co/d/ae5vQPN, but the wires I have are solid copper and I'm not sure crimping solid wire is ok.

Now I'm considering Wago 221-613.

At the top of the 12"x12" box I will use a Dinkle assembly DK6N (1 in, jumper, 2 out), although the DK4N 10AWG/30A would be fine too. If I had space, I would add another row of DK6N between breakers and SPDs instead of the Wagos just because it would look a lot better.

 

[timselectric]

Don't crimp solid wire. I don't trust Wago's for anything other than a single light fixture.
Remember that this is for surge protection. The connection needs to handle the surge. Lugs or wire nuts, are the only things that I would trust.

 

[Gotshocked!]

Don't crimp solid wire. I don't trust Wago's for anything other than a single light fixture.
Remember that this is for surge protection. The connection needs to handle the surge. Lugs or wire nuts, are the only things that I would trust.

I've got a similar problem and posted it on a thread I started, then I found this thread while searching on google.
I've got my 10ga pv wire but the wire from the midnight solar 600 spd's won't fit, certainly not safely.
In your opinion, would it be acceptable to make a pigtail out of spare pv wire and then use wire nuts to attach the pv wire from the panels and the wire from the spd's to said pigtail?

 

[timselectric]

I've got a similar problem and posted it on a thread I started, then I found this thread while searching on google.
I've got my 10ga pv wire but the wire from the midnight solar 600 spd's won't fit, certainly not safely.
In your opinion, would it be acceptable to make a pigtail out of spare pv wire and then use wire nuts to attach the pv wire from the panels and the wire from the spd's to said pigtail?
View attachment 217194

In any other situation I would say yes. But for surge protection, you want to minimize length and connections.
What size wire did they come with?
Is it solid or stranded?
Is there enough room for a pin reducer?
If not, a wire nut is better than nothing.

 

[Gotshocked!]

Thank you very much for replying Tim.
The length will be very short. All 3 spd's are right under the mppt's.
I'm fairly certain they're 14 ga. That's the ga that works well with my wire strippers.
All the wire is stranded.
I didn't know about a pin reducer. This would except the 10 & 14 ga and then plug into the mppt. I will use these.

 

[Gotshocked!]

Called 5 supply companies and 1 new what I was talking about but none have anything this size.
Would an 8ga to 10 ga reducer like this do the trick?

8X Car Audio Amp Input Reducer 8 Gauge to 10 Gauge Wire Reducer Power and Ground | eBay

Type: Power cord reducer. 8PCSPower Wire Reducer. 8G to 10G amp input reducers. Material: zinc alloy.

www.ebay.com

 

[timselectric]

Called 5 supply companies and 1 new what I was talking about but none have anything this size.
Would an 8ga to 10 ga reducer like this do the trick?

I'm not familiar with that seller/ brand.
But I tend to avoid anything made for car audio systems.

 

[timselectric]

Would an 8ga to 10 ga reducer like this do the trick?

Yes, it should.

 

[meetyg]

I have seen off the shelf PV combiner boxes double tap the breaker for the SPD. Not saying this is ideal (a busbar would probably be best).
I have heard that if wire guage is the same, it's OK to double tap (but probably not more than two conductors per terminal).

 

[robbob2112]

double tap breakers have slots for 2 wires with the screw between them. They will have a diagram on the side saying it is a double tap.

NEC says you can only doubletap breakers that are designed for it.

I think were it me I would see if I had double tap breakers and if not I would pigtail 2 ends - one for breaker and one for the SPD.

 

[Gotshocked!]

I have seen off the shelf PV combiner boxes double tap the breaker for the SPD. Not saying this is ideal (a busbar would probably be best).
I have heard that if wire guage is the same, it's OK to double tap (but probably not more than two conductors per terminal).

Yeah, that meter box isn't gonna work. I'll have to go to a breaker in the load panel for the 300ac or just return that one and get something that'll fit inside the panel. If I connect the 300 to the load panel, then I'll have to cut a hole in the wall and install this thing. I'm not exactly excited about it.

MidNite Solar MNSPDFMB Flush Mount Kit

Shop MidNite Solar MNSPDFMB Flush Mount Kit online or call us, Solarflexion, at 800-942-2424 for your solar needs.

www.solarflexion.com

 

[Gotshocked!]

The guy in the video said that the 300 ac doesn't need a breaker. It's got it's own fuse. One can install it directly to the lugs.
Where would be best for me to locate this thing?
Can I just install it to the 200amp breaker? Whats the difference between that and installing it to the lugs?
I'm not sure why midnight solar advised me to connect it to a 30amp 2 pole.

 

[timselectric]

I would put a 30a breaker in for it.
You'll be glad that you did, when it's time to replace it.

 

[Kornbread]

So, a question, why not use the breaker slots available instead of Polaris connectors? Wish my meter's panel had those extra breaker mounts as it would make things a lot easier.

 

[Gotshocked!]

The breaker slots are between the grid and that 200 amp breaker. I think the 30 amp breaker would need to install after the 200 amp.
From what I understand, I'd have to rewire those bus bars so that they fall after the 200 amp. For that, I have to pull the meter and for that I'd have to use my grinder and cut the power companies lock off my box, a lock they installed because they thought I was stealing power once the solar was up and running. I actually wouldn't mind cutting off that lock.

Would it not be better to install it at the 200 amp? Even at both taps, if that were possible.
When the spd is on one side, on one of the 2 legs, I think it wouldn't protect as well as if it were on both legs.
What makes sense to me might not make any sense because I don't have a firm grip on electricity.

 

[Kornbread]

Are the spd similar to this, but for pv? intermatic surge protection

That breaker position would work for me. Put a 100amp breaker on it with runs to the shop and a couple ct's right above it. Done.

 

[Gotshocked!]

That's one example of what those bus bars are for, a shop.
I don't believe that installing a breaker there will protect my load panel and my solar inverter.
I don't think that those bus bars even connect to that 200 amp main shut off, therefore I believe I would have to rewire them. My neighbor who I helped do the ac side of my system said he had to rewire those bus bars in his meter box so he could use them for his generator.
I'm calling midnight solar today to see if I can somehow install this 300ac in this meter box.

 

[Gotshocked!]

I called midnight solar. They're undergoing maintenance, so emails only right now.

 

[Hedges]

I don't believe that installing a breaker there will protect my load panel and my solar inverter.
I don't think that those bus bars even connect to that 200 amp main shut off, therefore I believe I would have to rewire them. The breaker slots are between the grid and that 200 amp breaker. I think the 30 amp breaker would need to install after the 200 amp.

From what I understand, I'd have to rewire those bus bars so that they fall after the 200 amp. For that, I have to pull the meter and for that I'd have to use my grinder and cut the power companies lock off my box, a lock they installed because they thought I was stealing power once the solar was up and running. I actually wouldn't mind cutting off that lock.

Would it not be better to install it at the 200 amp? Even at both taps, if that were possible.
When the spd is on one side, on one of the 2 legs, I think it wouldn't protect as well as if it were on both legs.
What makes sense to me might not make any sense because I don't have a firm grip on electricity.

An SPD installed before the 200A breaker (e.g. on another breaker using those busbars), after the 200A breaker, or at your inverter, would protect inverter by absorbing surges.

Of course if breaker feeding SPD was turned off, it wouldn't protect.

As an aside,
The Polaris in that box have access from either side to each setscrew. The 3 positions are all used, each from one side.

I selected a Polaris large enough that I could slide insulated 3/0 wire through it. I stripped 1" of insulation off about 4" from the end of the wire. Polaris is clamped at that exposed middle point, and the 4" stub goes in to main breaker.

I also fed 20' of 2 awg through another tap of Polaris, connecting it in the middle. That provided two 10' feeder taps, which go to panels with 100A breaker/fuse. 4 connections from 2 Polaris taps.

For now I have plug-on SPD in each breaker panel. I may attach one more SPD of different characteristics (with OCPD in line) inside the box or hanging off it.

 

[Gotshocked!]

An SPD installed before the 200A breaker (e.g. on another breaker using those busbars), after the 200A breaker, or at your inverter, would protect inverter by absorbing surges.

If I can install it high up enough, it will protect the inverter and the load panel. That's what I'm looking to do.
I don't think I'd be doing this if it weren't for senville suggesting I get surge protectors for these mini splits. So I figure, I might as well protect the whole house and the inverter but it's proving to be a huge pain in my ass.

I didn't know feeder taps were also called polaris.

 

[Hedges]

Polaris is a multi-port connector. Popular for making feeder taps if not doing hot work. Insulation piercing connectors are used for hot work.

Feeder Tap is a term for a wire too thin to be protected by upstream fuse or breaker.
Requirements include at least 10% (?) of ampacity of source, < 10', in metal conduit.
They do get connected line-side, could see entire fault current of transformer.
Mine are load-side, after 200A breaker. I don't feel bad about 2 awg because it is larger than ground wire for 200A (about 1/3 of ampacity, I don't like 1/10th), sufficient to fast-trip breaker in case of short to conduit. Overloads would be handled by downstream OCP.

 

[Gotshocked!]

I'm not sure exactly what you've just written, but if I did understand it, I could probably get this 300 ac installed.

 

[Kornbread]

I'm not sure exactly what you've just written, but if I did understand it, I could probably get this 300 ac installed.

Those EE types ... sheez

Calling that connector a Polaris is kind of like calling those fancy paper napkins you blow your nose into a Kleenex.