Multiplus / Subpanel / Distribution panel / ground question

[JJJJ]

Ok this is a multipart question.

I am planning on running a 120v subpanel which will then connect to a Nema outlet and plug that will be used to connect the Multiplus to the grid as needed. I elected to use 10/3 wire (30 amps) due to the cost of 8/3 ( 50 amps).

From the Multiplus, I will take the AC out and place in a distribution panel which will go to numerous locations in the house.

I am aware of the need to separate the neutral and ground on the subpanel in order to avoid what has been called objectionable current.

The Multiplus requires a ground. Would I be able to attach it to the ground in the outlet which houses the Nema plug since it ties back to the subpanel and then back to the main?

Does the AC output of the Multiplus feed back in any way. In other words, if there is a short in one of the lines from the distribution box from the Multiplus, does it feed back through the unit to the AC source, the metal case ground of the Multiplus, or is a separate ground feed needed?

 

[sunshine_eggo]

Ok this is a multipart question.

I am planning on running a 120v subpanel which will then connect to a Nema outlet and plug that will be used to connect the Multiplus to the grid as needed. I elected to use 10/3 wire (30 amps) due to the cost of 8/3 ( 50 amps).

From the Multiplus, I will take the AC out and place in a distribution panel which will go to numerous locations in the house.

Like a critical load panel?

I am aware of the need to separate the neutral and ground on the subpanel in order to avoid what has been called objectionable current.

Generally, yes.

The Multiplus requires a ground. Would I be able to attach it to the ground in the outlet which houses the Nema plug since it ties back to the subpanel and then back to the main?

The MP has a programmable relay. When inverting, it engages an internal N-G bond. When passing through source AC, the relay opens and disengages the N-G bond.

Does the AC output of the Multiplus feed back in any way.

Only if configured to interact with grid. Default is no, and it requires a closely held password to enable it. It is essentially only a load or passthrough device for grid power.

What I think you need to do is:

1. Tie the critical panel into the main panel N-G bond, i.e., run N and G to the main panel.
2. Disable the ground relay in the MP.

Whether passing through AC or inverting, there is a N-G bond at the main panel and the main panel is presumably earthed.

 

[timselectric]

Since the Mult plus has a properly working N/G bonding relay.
Ground should be carried from the main service panel, through all equipment.
Neutral should be wired according to the manual.
Neutral and ground should be kept separate in all equipment and panels, except for the main service panel.

 

[JJJJ]

The purpose of the subpanel is to use the grid to charge the batteries via the Multiplus in a low battery power, low solar condition. The output from the Multiplus will be feeding lines that will be separate from the house wiring. In a sense they will be redundant lines that are wired separately from the house current. For simplicity sake I will simply unplug from the grid line and plug into the separate Multiplus battery powered system which until solar is installed will operate as a UPS system for lighting and a freezer.

If the output box from the Multiplus is a critical load panel then the answer to above is yes.

 

[timselectric]

The purpose of the subpanel is to use the grid to charge the batteries via the Multiplus in a low battery power, low solar condition. The output from the Multiplus will be feeding lines that will be separate from the house wiring. In a sense they will be redundant lines that are wired separately from the house current. For simplicity sake I will simply unplug from the grid line and plug into the separate Multiplus battery powered system which until solar is installed will operate as a UPS system for lighting and a freezer.

If the output box from the Multiplus is a critical load panel then the answer to above is yes.

That's how it should be wired. But, you don't need to unplug and plug in to the difference sources. The mult plus has a built-in transfer switch.

Edit: I'm not familiar with the different Multiplus models. I'm assuming that yours has an AC input.

 

[timselectric]

FYI
The Multiplus is a tier one inverter.
It doesn't have any of the neutral and ground issues that you may have read about in this forum.
You pay more for it, so that you don't have to deal with any problems.

 

[JJJJ]

This video does a great job of presenting my thoughts. I am not endorsing any products here but it discusses the concepts I envisioned. Thanks to everyone who offered suggestions, it is very much appreciated! If there are other thoughts, as always I welcome them. The video is a little lower and you may need to scroll to it.

120V AC Distribution Panel

This 120V AC Breaker Box by Progressive Dynamics and a sleek and compact solution to delivering 120V AC power to all of your 'standard' household outlets, electric hot water heaters, air conditioners, and other 120V

shop.explorist.life

 

[sunshine_eggo]

FYI
The Multiplus is a tier one inverter.
It doesn't have any of the neutral and ground issues that you may have read about in this forum.
You pay more for it, so that you don't have to deal with any problems.

It still needs to be properly configured. In this scenario, the ground relay needs to be disabled.

 

[timselectric]

It still needs to be properly configured. In this scenario, the ground relay needs to be disabled.

I disagree
Without a N/G bond, the load breakers won't trip if a hot wire shorts to ground.

 

[sunshine_eggo]

Isn't the N-G bond at the panel? If the ground relay is enabled, and you have a N-G bond at the panel, you'll get two N-G bonds when the inverter is inverting. Hello, objectionable current.

 

[timselectric]

Isn't the N-G bond at the panel? If the ground relay is enabled, and you have a N-G bond at the panel, you'll get two N-G bonds when the inverter is inverting. Hello, objectionable current.

If you are talking about the loads panel, then no.
The neutral and ground should be separated there.
Otherwise, when connected to grid power "Hello".

 

[sunshine_eggo]

If you are talking about the loads panel, then no.
The neutral and ground should be separated there.
Otherwise, when connected to grid power "Hello".

N-G bond @ main panel.
G is also earthed from there somewhere, right?
No N-G bond in loads panel (agree. Should be tied into ground @ main panel though)
Then inverter provides N-G bond and ground is still earthed at the main panel.

I think I screwed up when I thought the N needed to be common (but unbonded) between main and load panels.

That's how it should be wired. But, you don't need to unplug and plug in to the difference sources. The mult plus has a built-in transfer switch.

Edit: I'm not familiar with the different Multiplus models. I'm assuming that yours has an AC input.

Victron Phoenix: Inverter only. No AC input/charger.
Victron Multiplus: Phoenix + AC input/charger
Victron Quattro: Multiplus + second AC input (e.g., grid + genny, but only one active at a time with AC-in 1 the favored if both available).

 

[timselectric]

Victron Phoenix: Inverter only. No AC input/charger.
Victron Multiplus: Phoenix + AC input/charger
Victron Quattro: Multiplus + second AC input (e.g., grid + genny, but only one active at a time with AC-in 1 the favored if both available).

Thanks
The Multiplus is the only one I have seen. And didn't know if there were different versions of it.

 

[sunshine_eggo]

Thanks
The Multiplus is the only one I have seen. And didn't know if there were different versions of it.

There are, but those are the baseline differences in terms of major functions. There are also a variety of different battery voltage and power outputs that don't line up between models, e.g., there's a 48V/5000VA-120VAC Quattro, but there is no equivalent Multiplus.

 

[JJJJ]

Page 59 and 60 of the Victron wiring diagram PDF seem to provide some clues. I am not an electrician so please forgive me if I am not interpreting this correctly.

It would appear that one feeds both the ground from the frame of the inverter charger and distribution panel to the ac source ground.

So main panel with bonded neutral ground to subpanel NG unbonded to 10/3 cable to receptacle. Ground from frame of inverter charger and distribution panel both grounded to receptacle which created active ground back through wiring to main and ground even if unplugged.

If this is true then this would be the ground connection on the receptacle for the plug I will be installing. In this manner ground will always be active even if the plug is disconnected.

 

[FilterGuy]

Is there any type of diagram for what you are proposing? It would be useful to have one so we are all discussing the same thing.

 

[tomy2]

Is there any type of diagram for what you are proposing? It would be useful to have one so we are all discussing the same thing.

Speaking of load panels, I ordered an EG4 3k inverter and I have a small 125 Amp GE box that I want to use as a load panel. In order to get 7 120v circuits into it, I will need to use thin breakers (20 amp THQP breakers). I have never used these thin breakers before and wonder if they are up to par? Also the manual calls for a 30 amp breaker for the input line from the invertrer. Could I just use an inline 30amp fuse instead, so I don't waste another space in the box?

 

[timselectric]

Speaking of load panels, I ordered an EG4 3k inverter and I have a small 125 Amp GE box that I want to use as a load panel. In order to get 7 120v circuits into it, I will need to use thin breakers (20 amp THQP breakers). I have never used these thin breakers before and wonder if they are up to par? Also the manual calls for a 30 amp breaker for the input line from the invertrer. Could I just use an inline 30amp fuse instead, so I don't waste another space in the box?

You should create your own thread. So that it doesn't confuse the answers to the question in this thread.

 

[JJJJ]

 

[timselectric]

I don't see the purpose for the 120v sub panel.
Unless it also feeds something else, not shown.
But other than that, I don't see anything wrong with it.