How do I go from an AC plug on the inverter, to a breaker box?

[ADDvanced]

I searched but most answers are for huge residential systems. I have a solar 'shed' with 400Ah of lithium batteries, and 700 watts of solar on the roof. I wired the interior of the shed for AC, and my inverter is a Victron Phoenix 1200w with a single AC output receptacle.

I'm unclear on how to go from the AC plug, to a breaker box. I'd like to add a fuse box just so I can have some seperation of circuits.

 

[time2roll]

No breaker box needed. 1200w inverter will shut down before #14 wire gets warm or a 15a breaker trips.
J-Box with some switches would be fine.

Otherwise put a replacement plug onto some #14 romex.

 

[Supervstech]

If you must feed into a panelbox, romex or so cord with a nema 14-15 cord end can do it, but if the panel has alternate energy source capabilities, you would be making a suicide cord...

 

[12VoltInstalls]

Buy the shortest SOO 10ga (12 is fine for that, even 14) cord and cut the female end off. Wire it into your subpanel-configured breaker box- make sure you use a proper ‘gland’ or clamp (aka connector) to enter the panel. Blk goes to breaker bus lug, White goes to neutral bus, bare/green goes to isolated ground bus

 

[Road Runner]

I wired the interior of the shed for AC,

Per NEC, (National Electrical Code), the branch circuit receptacle must be GFCI protected.

Per NEC you will need to drive at least one 5/8" x 8ft ground rod outdoors to establish a grounding electrode system for the electrical service.
A minimum #6 copper ground wire will connect from the ground rod. (An approved ground rod clamp must be used.)
Example: https://www.grainger.com/product/2KXN2?gucid=N:N:FPL:Free:GGL:CSM-1946:tew63h3:20501231

Where does the other end of the #6 copper ground wire connect inside the shed?
Depends...
Is the inverter neutral bonded to the metal chassis inside the inverter?
OR,
Is the neutral Floating above ground in the inverter? (Not bonded to chassis).

Romex cannot be used for a power cord to connect the inverter to the panel.

Here is a good 2 space load center panel:

https://www.lowes.com/pd/Square-D-70-Amp-2-Spaces-4-Circuit-Main-Lug-Load-Center/3135851

 

[Vigo]

Good old NEC..

Still, props for posting it up even if it does tempt me to make an ass of myself with commentary. If the code itself was capable of starting fires my house would surely have burned down by now. Luckily only reality can do that.

 

[mikefitz]

The Victron 1200 inverter is a class 1 product that needs case earthed. With distributed appliances and multiple outlets idealy you need an earth point and earth leakage protection, ( RCD , GFCI), which thus needs neutral to earth bond in the inverter.
As supplied the Victron 1200 inverter has floating outputs but can be internally modified to have a neutral to protective earth bond, (see manual).

 

[Road Runner]

The Victron 1200 inverter is a class 1 product that needs case earthed. With distributed appliances and multiple outlets idealy you need an earth point and earth leakage protection, ( RCD , GFCI), which thus needs neutral to earth bond in the inverter.
As supplied the Victron 1200 inverter has floating outputs but can be internally modified to have a neutral to protective earth bond, (see manual).
View attachment 185678

As supplied the Victron 1200 inverter has floating outputs

If the OP is determined to install an electrical load center panel, branch circuit wiring, with a receptacle outlet, if it were me (to be compliant with NEC and more importantly with the AHJ, Authority Having Jurisdiction, in his area), I would bond the neutral at the electrical load center panel. Not at the inverter.

The Mother Earth connection, therein ground rod, and bare # 6 solid copper ground wire would connect to the neutral/ground bar. Supplied Green Bonding Screw installed bonding the neutral/ground bar to the metal enclosure of the load center panel.

The case/chassis of the inverter will be grounded by the EGC, (Equipment Grounding Conductor), in the power cord.

Note: A 5-15R duplex GFCI receptacle is a lot cheaper than a 15 amp GFCI circuit breaker.

Note: The main purpose of the Mother Earth connection, (driven ground rod), is for lightning protection.

.

 

[12VoltInstalls]

main purpose of the Mother Earth connection, (driven ground rod), is for lightning protection

For the panels, yes.
In a totally offgrid system (including the generator if any) where a N-G bond is derived in the panel and the output H N G is GFCI protected in some fashion it is unclear to me why a driven-in-dirt ground rod adds any safety to a system that has no circuit potential to the dirt other than after you connect the ground rod. Even outdoors with an older not-double-insulated tool leaking to/through its housing any current will immediately disconnect the GFCI that is present.

With any grid/powerco connection, however, the dirt on the ground always has circuit potential with the grid; you would neither want to connect a “second” ground rod to that system in a non-compliant manner nor establish the bond in a subpanel. I digress.

NEC or not: in an offgrid independent source of power with no circuit interactions to the grid whatsoever I’m not certain ‘earthing’ the system provides any advantages whatsoever.

I’m not being obstinate or whatever but I’ve yet to read any explanation other than lightning that makes sense to me. The panel frames should be independently grounded for lightning but “in my mind” the equipment on the interior is probably immune to lightning due to not having potential with the dirt/earth and the Van De Graf Effect.
I’ll gladly concede should a reasonable explanation of the potential (lightning vulnerability) of a floating circuit be provided but this is the current opinion I have arrived at regarding a dirt/earth connection to an offgrid system.

 

[Mattb4]

For the panels, yes.
In a totally offgrid system (including the generator if any) where a N-G bond is derived in the panel and the output H N G is GFCI protected in some fashion it is unclear to me why a driven-in-dirt ground rod adds any safety to a system that has no circuit potential to the dirt other than after you connect the ground rod. Even outdoors with an older not-double-insulated tool leaking to/through its housing any current will immediately disconnect the GFCI that is present.

...

It gets a bit complicated but by bonding all metal components of your electrical setup to a ground rod you know a good system ground plain exists. This can not be done with mobile applications. But for a fixed location it makes sense to do. Thus when you create a NG bond it is a real NG bond and not just an added neutral wire of bare copper or with green insulation.

Frankly I am not a fan of GFCI after inverters or generators leading to a distribution point or panel. Before an outlet on a individual circuit OK.

At any rate ground discussions can get intense. There are some strong opinions around the subject. I give mine and know other very intelligent folks disagree. Bit why using the NEC helps minimize arguments.

 

[Road Runner]

For the panels, yes.
In a totally offgrid system (including the generator if any) where a N-G bond is derived in the panel and the output H N G is GFCI protected in some fashion it is unclear to me why a driven-in-dirt ground rod adds any safety to a system that has no circuit potential to the dirt other than after you connect the ground rod. Even outdoors with an older not-double-insulated tool leaking to/through its housing any current will immediately disconnect the GFCI that is present.

With any grid/powerco connection, however, the dirt on the ground always has circuit potential with the grid; you would neither want to connect a “second” ground rod to that system in a non-compliant manner nor establish the bond in a subpanel. I digress.

NEC or not: in an offgrid independent source of power with no circuit interactions to the grid whatsoever I’m not certain ‘earthing’ the system provides any advantages whatsoever.

I’m not being obstinate or whatever but I’ve yet to read any explanation other than lightning that makes sense to me. The panel frames should be independently grounded for lightning but “in my mind” the equipment on the interior is probably immune to lightning due to not having potential with the dirt/earth and the Van De Graf Effect.
I’ll gladly concede should a reasonable explanation of the potential (lightning vulnerability) of a floating circuit be provided but this is the current opinion I have arrived at regarding a dirt/earth connection to an offgrid system.

Putting aside electrical safety code(s). Therein, NEC and AHJ.

The owner manual states the inverter shall be earthed for electrical safety.

https://www.victronenergy.com/Manuals/phoenix/Phoenix12_1000/GBISM010037000_REV0020030304.pdf

See Installation
A ground lug is provided on the inverter for earthing.

IF the OP was not installing an electrical load center panel, branch circuit wiring, and a receptacle outlet in the shed and was only using the inverter as a plug and play AC SDS, (Separately Derived System), NEC and or AHJ, would not be at play, imo...

Even if the SDS AC inverter is used as a plug and play unit the Owner Manual electrical safety rules apply on earthing, imo...



EDIT: I forgot to address this

main purpose of the Mother Earth connection, (driven ground rod), is for lightning protection

@12VoltInstalls Response:

For the panels, yes.

Solar panels...
Why??? Lightning protection?

 

[sunshine_eggo]

Summary of what I would do (please correct me if wrong):

Shed should have a ground rod driven into the earth.
Any other conductive ground penetrations (copper pipe, etc.) bonded to ground rod.
Roof mounted PV FRAMES should also be bonded to ground rod.
AC panel G bonded to ground rod.
AC panel N-G bond
Phoenix set to floating neutral.
Phoenix case lug bonded to G.

Phoenix connected to panel:

If you must feed into a panelbox, romex or so cord with a nema 14-15 cord end can do it, but if the panel has alternate energy source capabilities, you would be making a suicide cord...

Buy the shortest SOO 10ga (12 is fine for that, even 14) cord and cut the female end off. Wire it into your subpanel-configured breaker box- make sure you use a proper ‘gland’ or clamp (aka connector) to enter the panel. Blk goes to breaker bus lug, White goes to neutral bus, bare/green goes to isolated ground bus

No breaker box needed. 1200w inverter will shut down before #14 wire gets warm or a 15a breaker trips.
J-Box with some switches would be fine.

Otherwise put a replacement plug onto some #14 romex.

 

[Road Runner]

Summary of what I would do (please correct me if wrong):

Shed should have a ground rod driven into the earth.
Any other conductive ground penetrations (copper pipe, etc.) bonded to ground rod.
Roof mounted PV FRAMES should also be bonded to ground rod.
AC panel G bonded to ground rod.
AC panel N-G bond
Phoenix set to floating neutral.
Phoenix case lug bonded to G.

Phoenix connected to panel:

"AC panel G bonded to ground rod."
"AC panel N-G bond"

Because the insulated neutral bar will be bonded to the panel enclosure, via the green bonding screw, the neutral bar can be used for neutral conductors as well as equipment grounding conductors. ( Only one neutral conductor installed in a lug.) The solid bare #6 copper wire from the ground rod connects to the bonded neutral/ground bar. If you choose to install a separate ground bar in the electrical panel for equipment grounding conductors, the solid bare #6 ground wire from the ground rod still connects to the bonded neutral bar.

Any other conductive ground penetrations (copper pipe, etc.) bonded to ground rod.

Each ground wire connected to the ground rod requires a separate ground clamp.
I would suggest this. Intersystem Bonding Termination.

Intersystem Bonding Termination IBTB - The Home Depot

This Intersystem Bonding Termination is designed for use in residential or small commercial facilities. Reliability and safety is ensured as it is cULus listed and CSA listed and meets 2008 NEC requirements.

www.homedepot.com

It clamps to the solid bare (UNCUT) #6 ground wire. ( The #6 Grounding Electrode Conductor must be continuous from ground rod clamp to the bonded neutral bar in the electrical panel. No splices.

​

As for the power cord that will plug into the inverter to feed the electrical panel.
NM sheathed cable, (Romex is a Trade Name) is not Listed, nor designed or approved by the manufacturer for use as a plug connected power cord.
See 2020 NEC Article 400.6. Note NM cable is not on the list of cables listed for use as a flexible power cord. If the inverter was hard wired to the electrical panel it could be used if supported...

You can build your own power cord. I would use at least 12/3. Buy and install a good male plug. Buy a strain relief connector for the cord diameter of cord you buy.
Example of Strain Relief connectors:
https://www.homedepot.com/s/strain relief connector for 12/3 rubber cord?NCNI-5

 

[Supervstech]

For the panels, yes.
In a totally offgrid system (including the generator if any) where a N-G bond is derived in the panel and the output H N G is GFCI protected in some fashion it is unclear to me why a driven-in-dirt ground rod adds any safety to a system that has no circuit potential to the dirt other than after you connect the ground rod. Even outdoors with an older not-double-insulated tool leaking to/through its housing any current will immediately disconnect the GFCI that is present.

With any grid/powerco connection, however, the dirt on the ground always has circuit potential with the grid; you would neither want to connect a “second” ground rod to that system in a non-compliant manner nor establish the bond in a subpanel. I digress.

NEC or not: in an offgrid independent source of power with no circuit interactions to the grid whatsoever I’m not certain ‘earthing’ the system provides any advantages whatsoever.

I’m not being obstinate or whatever but I’ve yet to read any explanation other than lightning that makes sense to me. The panel frames should be independently grounded for lightning but “in my mind” the equipment on the interior is probably immune to lightning due to not having potential with the dirt/earth and the Van De Graf Effect.
I’ll gladly concede should a reasonable explanation of the potential (lightning vulnerability) of a floating circuit be provided but this is the current opinion I have arrived at regarding a dirt/earth connection to an offgrid system.

Because faults exist...
Because electricity is an electromagnetic wave, not a hose containing electrons...
Because metal and insulation equals capacitor...
Because vibration of atoms induce current.
The number of times i have gotten a shock from an ungrounded inverter is up there.
Having the earth as a reference point allows safety equipment a common plane for protection.

 

[12VoltInstalls]

Solar panels...
Why??? Lightning protection?

Yes. So it diffuses there instead of feeds the house with lightning by traveling the solar cables. I believe that is NEC, too

ungrounded inverter

that would be not grounded anywhere.
If the case is grounded to the circuit’s central ground point then it’s grounded. Adding a dirt rod for an offgrid system in my mind then incorporates the earth as part of the potential circuit when it doesn’t need to be for safety.
Not being argumentative. I just don’t see the point of a ground in dirt When it’s not part of the circuit potential

Because faults exist...
Because electricity is an electromagnetic wave, not a hose containing electrons...
Because metal and insulation equals capacitor...
Because vibration of atoms induce current

that has merit

 

[Road Runner]

.
Road Runner Said:

Solar panels...
Why??? Lightning protection?

Yes. So it diffuses there instead of feeds the house with lightning by traveling the solar cables. I believe that is NEC, too

that would be not grounded anywhere.
If the case is grounded to the circuit’s central ground point then it’s grounded. Adding a dirt rod for an offgrid system in my mind then incorporates the earth as part of the potential circuit when it doesn’t need to be for safety.
Not being argumentative. I just don’t see the point of a ground in dirt When it’s not part of the circuit potential

that has merit

Yes. So it diffuses there instead of feeds the house with lightning by traveling the solar cables. I believe that is NEC, too

My response:
Exactly... 2020 NEC 690.47
~
In the event of a nearby lightning strike the transient high voltage/high current event will be diverted to Mother Earth.

FWIW: The lower the ground rod to soil resistance the better the earthing electrode, (ground rod), can dissipate the electrical currents to earth. Simple Ohms Law.

NEC only requires the ground rod to soil resistance of 25 ohms or less... The only way to know what you have is to measure it. NEC doesn't require it though. Only if one ground rod is driven is testing required. And that's only if the AHJ Electrical Inspector asks for verification, see the test report.

NEC 2020 250.53 Grounding Electrode System Installation.
250.53 (A)(2) Supplemental Electrode Required.

See Exception:

It's cheaper to just install a second ground rod. No further testing is required. The single rod could of tested 100 ohms. Without testing again who knows what the test would be with the two rods. Less than 25 ohms?

IEEE emerald book recommends for commercial/ industrial an electrode to soil resistance of 5 ohms or less.

ungrounded inverter

that would be not grounded anywhere.
If the case is grounded to the circuit's central ground point then it's grounded. Adding a dirt rod for an offgrid system in my mind then incorporates the earth as part of the potential circuit when it doesn't need to be for safety.
Not being argumentative. I just don't see the point of a ground in dirt When it's not part of the circuit potential

The bonded grounded neutral conductor in the electrical panel connection to Mother Earth is for the same reason as the solar panels mounted on the roof. A near by lightning strike can enter the shed as well.

In the case of a near by lightning strike there could very well be a lightning transient event on the 120V AC electrical wiring and associated equipment in the shed. The electrical service Grounding Electrode System, (earth connection), just might save the inverter from being fried. The Lightning high voltage transient path is to Mother Earth. The best low resistance path to earth is through the grounding electrode conductor, that's connected to the bonded neutral bar in the electrical panel, to the grounding electrode (ground rod) driven in the earth.

NEC requires it... And I can only assume the State, or local governing body, AHJ, requires it. The AHJ has the final say...

Food for thought. NEC is bare minimum electrical safety standards. It is not intended as a design specification or an instruction manual for untrained persons.

2020 NEC Article 90
Introduction

90.1 (A) Practical Safeguarding.

90.1 (B) Adequacy.
.

 

[12VoltInstalls]

Again- lest emotionless text convey an unintended attitude of some sort- please allow me to restate that I am not feeling combative, being argumentative, nor questioning the veracity of anyone’s opinion.
I am debating - but merely debating for the purpose of hopefully quelling my own vacillating dichotomy in this area.

In the event of a nearby lightning strike the transient high voltage/high current event will be diverted to Mother Earth.

No question that the panel frames should be bonded and earth/dirt grounded.

The ‘murkiness’ for me of dirt/earth grounding an absolutely no-grid independent offgrid system is that:

1. Since solar cables are directly wired from the panels to whatever form of SCC is used, and assuming a ground mount array, the pos(+) and neg(-) are buried in conduit and thereby NOT “grounded” in any fashion other than the panel frames and mounts at the array. Which may or may not be a sufficient barrier to panel traces and solar cables from “picking up” a lightning discharge current.
2. If I roof mounted panel array, the frames should still be earth/dirt grounded (and my thought is this should be a direct cable on the exterior of the structure to the earth/dirt ground rod(s)). - the pos(+) and neg(-) solar cables are also yet floating as in 1) above
3. I know a local woman who has been offgrid since 2001. Only utility wiring coming to the house is/was a buried phone line that was fed from a pole nearly 3/4 mile away. About ten-ish years ago lightning struck the power line poles (that hung phone/telecom wires) near the 3/4-mile away buried cable connection and the discharge backfed her cordless phone charging base into her breaker panel (where N-G bond was derived) and then likely dissipated to the earth/dirt ground rod. Except that her inverter that fed the house breaker panel was fried. No other equipment nor the well pump were affected. So I can see that perhaps in this circumstance the earth/dirt ground rod perhaps averted further damage. Yet I wonder: if a system is an entirely offgrid- no distant or near connections other than cables for a ground mount array- would the ground rod offer any effective purpose? Or would it increase lightning strike potential since it now “encourages” the offgrid wiring to be at the same potential as the dirt that attracts or provisions an atmospheric discharge?

In the case of a near by lightning strike there could very well be a lightning transient event on the 120V AC electrical wiring and associated equipment in the shed. The electrical service Grounding Electrode System, (earth connection), just might save the inverter from being fried.

..,though in the above real-life event it did not, could not, for whatever reason(s).

So as far as 120VAC/240VAC safety is concerned- independent of lightning discharge- I’m assuming that not earth/dirt grounding the AC is of no practical consequence (NEC aside). Not that I’m encouraging anyone should disregard NEC, rather speaking in purely practical terms of the risks of becoming part of a 120VAC/240VAC circuit.

I really appreciate the responses to the little sidebar appendage to this thread so far. Thank you.

 

[scrubjaysnest]

.
Road Runner Said:

Yes. So it diffuses there instead of feeds the house with lightning by traveling the solar cables. I believe that is NEC, too






My response:
Exactly... 2020 NEC 690.47
~
In the event of a nearby lightning strike the transient high voltage/high current event will be diverted to Mother Earth.

FWIW: The lower the ground rod to soil resistance the better the earthing electrode, (ground rod), can dissipate the electrical currents to earth. Simple Ohms Law.

NEC only requires the ground rod to soil resistance of 25 ohms or less... The only way to know what you have is to measure it. NEC doesn't require it though. Only if one ground rod is driven is testing required. And that's only if the AHJ Electrical Inspector asks for verification, see the test report.

NEC 2020 250.53 Grounding Electrode System Installation.
250.53 (A)(2) Supplemental Electrode Required.

See Exception:

It's cheaper to just install a second ground rod. No further testing is required. The single rod could of tested 100 ohms. Without testing again who knows what the test would be with the two rods. Less than 25 ohms?

IEEE emerald book recommends for commercial/ industrial an electrode to soil resistance of 5 ohms or less.



The bonded grounded neutral conductor in the electrical panel connection to Mother Earth is for the same reason as the solar panels mounted on the roof. A near by lightning strike can enter the shed as well.

In the case of a near by lightning strike there could very well be a lightning transient event on the 120V AC electrical wiring and associated equipment in the shed. The electrical service Grounding Electrode System, (earth connection), just might save the inverter from being fried. The Lightning high voltage transient path is to Mother Earth. The best low resistance path to earth is through the grounding electrode conductor, that's connected to the bonded neutral bar in the electrical panel, to the grounding electrode (ground rod) driven in the earth.

NEC requires it... And I can only assume the State, or local governing body, AHJ, requires it. The AHJ has the final say...

Food for thought. NEC is bare minimum electrical safety standards. It is not intended as a design specification or an instruction manual for untrained persons.

2020 NEC Article 90
Introduction

90.1 (A) Practical Safeguarding.

90.1 (B) Adequacy.
.

When the county inspector came out for the electrical inspection he asked why 2 ground rods and why #6 wire. I replied I had the wire and dry sand doesn't conduct well. This was in 2000. Codes were different then. 18 inch direct burial ok. I ran conduit 2 feet down.

 

[Road Runner]

When the county inspector came out for the electrical inspection he asked why 2 ground rods and why #6 wire. I replied I had the wire and dry sand doesn't conduct well. This was in 2000. Codes were different then. 18 inch direct burial ok. I ran conduit 2 feet down.

@scrubjaysnest

Good Morning, Happy New Year!

Just a clarification note. This quite was a response from 12VoltInstalls to a post of mine to an earlier post of 12VoltInstalls. (Can get confusing at times.)

Yes. So it diffuses there instead of feeds the house with lightning by traveling the solar cables. I believe that is NEC, too

As for this:

When the county inspector came out for the electrical inspection he asked why 2 ground rods and why #6 wire. I replied I had the wire and dry sand doesn't conduct well. This was in 2000. Codes were different then. 18 inch direct burial ok. I ran conduit 2 feet down.

Like I said in my last posted message the AHJ has the final say. In most cases even the electrical code under the governing body jurisdiction AHJ is bare minimum electrical safety standards/requirements. You can exceed minimum electrical requirements/standards. You just can't go below the standards/requirements of the AHJ in your area. Check out which year NEC Florida is working under.

Note this site says Florida adopted the 2020 NEC on 12/31/2023. (Florida had been working under the 2017 NEC.)

Florida

2020​

Effective 12/31/2023

NEC® Adoption List

Verified here:
NFPA

Learn where the NEC is enforced. | NFPA

Discover which edition of the NFPA 70, National Electrical Code® (NEC® ) is enforced in your state.

www.nfpa.org

.
.
You said in 2000 you had the inspection. There is a good chance the AHJ in your area, (County inspector) was not working under the 1999 NEC. Just a guess the 1996 NEC edition.
In the 1996 NEC Article 250-83. Rod and Pipe Electrodes.
Rod shall not be less than 8 ft.

250-83(c) (2)
Rod shall not be less than 5/8" in diameter.

250-84. Resistance of Made Electrodes.

A single electrode consisting of rod, pipe, or plate that does not have a resistance to ground of 25 ohms or less shall be augmented by one additional electrode of any of the types specified in sections 251-81 or 250-83.

25 ohms or less would require testing. Expensive for test even back then.

Specified in 251-81 or 250-83.

250-83(c). Rod and Pipe Electrode.
Ground rod...

250-81(a). Metal Underground Water Pipe.
In contact with earth more than 10 ft or more. This is a round robin here, the way I read it, says water pipe shall be augmented by one additional approved electrode. Example, ground rod.

How deep is the horizontal metal potable water line in the area in Florida you had inspected in 2000? (If Metal)... In my state they are over 4 ft deep because of freezing due to the cold weather here in the winter.
Back in 1996 NEC I could have got by using only 1 ground rod and the incoming copper potable water line. At least the way I read 1996 NEC. Again the AHJ has the final say.
I would have to research what year NEC no longer allowed a metal underground water pipe to be used for meeting the 25 ohm or less rule for a single ground electrode.

Food for thought:
2020 NEC 90.1

(B) Adequacy. This Code contains provisions that are considered necessary for safety. Compliance therewith and proper maintenance result in an installation that is essentially free from hazard but not necessarily efficient, convenient, or adequate for good service or future expansion of electrical use.

.

 

[12VoltInstalls]

Can get confusing at times

At least I responded in the right thread…