EG4 GridBOSS Deep Dive

[zanydroid]

Your system is rather complex enough to merit putting time into drawing a diagram with all components

Big missing detail is if the service is 400A or 200A

Also I’m not sure about backing up Enphase system, potentially you can drain gridboss system then drain Enphase but it’s likely your flexibility will be limited even if it is doable

 

[TacoMeat]

Question - with a gridboss and 2 EG4 inverters.

Could you have one inverter export to grid and the other do no export? Trying to keep design simple as my provider wants a PV production meter and I'd rather not be using combiner boxes etc.

Both inverters would be connected shared batteries.

 

[DIYrich]

Panel 2 is an Enphase system at the moment and also has a Critical Load Panel running off of it

I want to use the Grid Boss and Flex Boss system, but I only want to use whatever works for Panel 2 and the CLP. But I want everything on Panel 2 and the CLP backed up. So, right now, GRID---> 200A Panel 1 + (200A Panel 2 + CLP).

So where do I connect the Grid Boss in this setup?

Grid -> Grid Boss -> Panel 2

Consider moving the Enphase to a Smart Load connection of the Grid Boss.

 

[famtraveler]

Your system is rather complex enough to merit putting time into drawing a diagram with all components

Big missing detail is if the service is 400A or 200A

Also I’m not sure about backing up Enphase system, potentially you can drain gridboss system then drain Enphase but it’s likely your flexibility will be limited even if it is doable

400A service

 

[Adam De Lay]

Question - with a gridboss and 2 EG4 inverters.

Could you have one inverter export to grid and the other do no export? Trying to keep design simple as my provider wants a PV production meter and I'd rather not be using combiner boxes etc.

Both inverters would be connected shared batteries.

Maybe, but I guess I'm not sure why combiner boxes would be an issue. No matter what, you would feed PV into your 2 EG4 inverters and they would push power back up to the grid.

 

[timselectric]

Question - with a gridboss and 2 EG4 inverters.

Could you have one inverter export to grid and the other do no export? Trying to keep design simple as my provider wants a PV production meter and I'd rather not be using combiner boxes etc.

Both inverters would be connected shared batteries.

The gridboss is the combiner.

 

[TacoMeat]

The gridboss is the combiner.

Agree but I have one of the stupid providers that need a PV Production Meter on top of the normal bi-direction meter. I'm hopeful that I can get away with a meter going back to grid or one after the Gridboss going to load.

It's just a lot of unneeded wall art that I'd rather not have. 2 inverters, into a combiner / breakers, into meter into disconnect into combiner into another combiner box. So much wall art that I do not have space for.

 

[timselectric]

Agree but I have one of the stupid providers that need a PV Production Meter on top of the normal bi-direction meter. I'm hopeful that I can get away with a meter going back to grid or one after the Gridboss going to load.

It's just a lot of unneeded wall art that I'd rather not have. 2 inverters, into a combiner / breakers, into meter into disconnect into combiner into another combiner box. So much wall art that I do not have space for.

View attachment 264436

Yup, that's pretty stupid. But if you want to play in their game, you have to play by their rules. Just another reason I don't have anything to do with the utility company.

 

[AntronX]

Looks like the way PV production meter is wired, it will also count your backup battery charging from generator and discharging to house loads during grid outage.

 

[zanydroid]

Looks like the way PV production meter is wired, it will also count your backup battery charging from generator and discharging to house loads during grid outage.

Exactly. This is the problem with a hybrid…

 

[Rocky Broad Solar]

Follow along with my GridBoss/Flexboss21 installation as well as the interview with James Showalter from EG4. Hoping to have my system fully installed by the end of January.

 

[thepetersms]

Agree but I have one of the stupid providers that need a PV Production Meter on top of the normal bi-direction meter. I'm hopeful that I can get away with a meter going back to grid or one after the Gridboss going to load.

It's just a lot of unneeded wall art that I'd rather not have. 2 inverters, into a combiner / breakers, into meter into disconnect into combiner into another combiner box. So much wall art that I do not have space for.

View attachment 264436

This is exactly how I have to set mine up since I already have a separate pv production meter. I've already purchased the 2 combiner panels on both ends of the meter. It does add costs to the installation for sure, not to mention more wire runs. It doesn't help that the gridboss only recommends copper wires.

 

[thepetersms]

Looks like the way PV production meter is wired, it will also count your backup battery charging from generator and discharging to house loads during grid outage.

I didn't even think of that... So with the pv production meter wired up coming off the eg4 inverters and into the gridboss, when there's a grid outage, the meter will think it's feeding power to the grid?

 

[timselectric]

I didn't even think of that... So with the pv production meter wired up coming off the eg4 inverters and into the gridboss, when there's a grid outage, the meter will think it's feeding power to the grid?

I guess that they (the power company) didn't think of that.
I would pump as much as I could during a power outage.
Make them pay for the hassle. lol

 

[timselectric]

Actually, if I was using the two meter setup. I would use one of the gridboss load circuits to charge the batteries. And circulate as much power as allowed through the production meter. Even with the round trip efficiency losses, it should still be a win.

 

[thepetersms]

I guess that they (the power company) didn't think of that.
I would pump as much as I could during a power outage.
Make them pay for the hassle. lol

I'm checking with my power company to see if the production meter is required. I originally asked if the two meters could be combined into one and they said no. They did say the pv production meter is only used for monitoring.

 

[thepetersms]

I'm checking with my power company to see if the production meter is required. I originally asked if the two meters could be combined into one and they said no. They did say the pv production meter is only used for monitoring.

Power company got back to me and they want the production meter left in place, bummer. Guess I'll have to wire it up as 18kpvs to combiner panel to production meter to combiner panel to gridboss inverter lugs. In the end I guess it's still a win as I'm getting rid of the back feed breaker. Still sucks that we have extra costs wire more wire, 2- combiner panels, and 4- 70amp breakers.

 

[thepetersms]

I have what might be a dumb question. I'm ordering all the wiring to hook up both of my eg4 18kpvs to the Gridboss. I have to install it using the highlighted method since I have to keep my PV production meter. Do I have to run a neutral and ground to the combiner box from the 18kpv?

 

[timselectric]

I have what might be a dumb question. I'm ordering all the wiring to hook up both of my eg4 18kpvs to the Gridboss. I have to install it using the highlighted method since I have to keep my PV production meter. Do I have to run a neutral and ground to the combiner box from the 18kpv?

Electrically no, but probably to pass the inspection.

 

[thepetersms]

Electrically no, but probably to pass the inspection.

Ok thanks. I'm running aluminum wire most of the run and then splice copper into the Gridboss so I'll go ahead and run all 4 lines to the combiner panels.
Pretty dumb that we can't run aluminum into the Gridboss.

 

[zanydroid]

I’m not convinced it’s OK to do line/line only. That may not result in balanced current within those cables or conduits which.

 

[TacoMeat]

Odd question - can I run my communications cable through the same conduit that my flexboss21 uses to the gridboss? Assume if so it has to be 600v rated etc. Also since mine will require the PV meter and disconnect does that change anything? Just wondering if there are rules that state you cannot run other wires through a disconnect and or meter that is not part of that disconnect / meter.

Trying to not run another conduit that would house the comms cable plus power for tigo tap.

 

[zanydroid]

Odd question - can I run my communications cable through the same conduit that my flexboss21 uses to the gridboss? Assume if so it has to be 600v rated etc. Also since mine will require the PV meter and disconnect does that change anything? Just wondering if there are rules that state you cannot run other wires through a disconnect and or meter that is not part of that disconnect / meter.

Trying to not run another conduit that would house the comms cable plus power for tigo tap.

Interesting, I tried to look up the exemption for "functionally associated" (this is the official NEC term) circuits, and I can't find dispensation for you to run CL2 wiring (which I thought was OK, and I've done before, albeit for a few feet). Welp.

Here's a good starting point to deep spiral into it.

Wire insulation in same raceways must match

I know it's in the NEC somewhere but I can't seem to find it. Isn't it a violation to run low voltage (say 300V) Belden cable in the same raceway as 600VAC rated wire? Would someone point me to the correct section? Thanks in advance.

forums.mikeholt.com

You should be OK to pull the CL2xxx signal cable outside of conduit. (You might need like CL2R or some other more stringent variant)

 

[FilterGuy]

Odd question - can I run my communications cable through the same conduit that my flexboss21 uses to the gridboss? Assume if so it has to be 600v rated etc. Also since mine will require the PV meter and disconnect does that change anything? Just wondering if there are rules that state you cannot run other wires through a disconnect and or meter that is not part of that disconnect / meter.

Trying to not run another conduit that would house the comms cable plus power for tigo tap.

• In general the NEC does not allow low voltage signall cabling to be in the same conduit as the power wires. However, there is an exception that allows it if the signaling is controlling the power lines. As you state, the insulation of the signalling has to be rated for the 600V.
• Some inspectors won't let you do it (They don't know or don't accept the exception). It is anybody's guess what your inspector will say.

However, it is always better to keep low-voltage signal wires and AC power wires separate to avoid noise getting on the signaling wires. This is true in general and even more true when dealing with inverters that tend to be noisy in the first place. If you can keep them separate, do so. Noise problems are typically very difficult to debug.

 

[zanydroid]

• In general the NEC does not allow low voltage signall cabling to be in the same conduit as the power wires. However, there is an exception that allows it if the signaling is controlling the power lines. As you state, the insulation of the signalling has to be rated for the 600V.

Do you have a reference to the exception? I tried to look for it actually just now, and I mostly found stuff that suggested it's not allowed

EDIT: for instance, the one I just pointed to above. And also, here's another

0-10 inside the same conduit

Hi, I understand that class 1 and class 2 wiring cannot be installed in the same raceway without a barrier but I'm wondering if I were to use #12 AWG THHN for both the high voltage (120V) and the 0-10 dimming controls if that would be code sufficient? I don't see why not but that's why I'm here

forums.mikeholt.com

If you have to pull a cable with stringent impedance/capacitance specs, you are screwed. I don't think that's the case for the CTs, but it is the case for Ethernet.