Utility requires separate red lever disconnect for battery?!

[albrittbrat]

I am in the process of commissioning my solar system. I have 40x talesun 395W panels on my roof, an EG4 18KPV hybrid inverter, and an EG4 280Ah indoor wall mount battery. The solar is already wired to the inverter and the inverter to the battery, all good there.

So after waiting a full month for my power company (Ameren IL) to get back to me on my solar/net metering application, they are saying I have to have a red lever disconnect between the meter base and the inverter - no problem there, can do that easily.

The problem is they are saying I have to have a separate red lever disconnect for my battery. The meter base is on one side of my house and the solar equipment is in the owners closet next to the main house panel, clear on the other side of the house. Over 100' away if you factor in up and down. You arent supposed to extend battery cables at all, much less hundreds of feet.

So my question is, does anyone know of any kind of remote control disconnect? Or a massive 48,000 Watt relay that doesn't humm horribly? The battery uses four 2/0 aluminum cables, two red and two black to connect to the inverter.

Thanks!

 

[Hedges]

You may have a way to "RSD" the battery. Some inverters or batteries have a shutdown signal.

I'm using a 3-pole disconnect switch, or a 2-pole with handle position microswitch. My older battery inverters don't have such a shutdown, but I can open a relay to shed the AC loads so at least no AC going anywhere.

Another idea is GigaVac high current relay. That could interrupt battery connection.

There are also Midnight/Carling 175A and 250A battery breakers (UL Listed), and a model with remote trip (not UL Listed).

 

[FilterGuy]

Is the Utility or the local building department insisting on the DC Disconnect?

The code just says the switch has to be in view of the battery. IMHO, The breaker on the battery satisfies the requirements.

This is what Copilot AI says:

>What does the NEC require for an ESS battery disconnect

Quick Answer:
The NEC requires that an Energy Storage System (ESS) have a readily accessible disconnecting means for all ungrounded conductors, and in one- and two-family dwellings, it must include an emergency shutdown function with an initiation device located outside the building.

Key NEC Requirements for ESS Battery Disconnects

• General Rule (NEC 706.15, 2020 & 2023 editions):
  • A disconnecting means must be provided for all ungrounded conductors derived from an ESS.
  • The disconnect can be integral to listed ESS equipment (e.g., built into the battery system).
  • It must be readily accessibleand either:
    • Located within sight of the ESS, or
    • Installed as close as practicable with durable field marking if not within sight.
  • The disconnect must be lockable in the open position per NEC 110.25.
• Emergency Shutdown (2023 NEC update):
  • For one- and two-family dwellings, the ESS must include an emergency shutdown function.
  • An initiation device must be located outside the building, plainly indicating “on” or “off.”
  • Switching to “off” must cease the export of power from the ESS to premises wiring.
• Options for Disconnect Location (NEC 706.15(B)):
  1. A disconnecting means located within the ESS.
  2. A disconnecting means located within sight and within 10 feet of the ESS.
  3. A disconnecting means not within sight, but capable of being locked open.
• Integrated Systems (UL 9540-listed ESS):
  • Many modern ESS units integrate battery management systems (BMS) and breakers that satisfy NEC disconnect requirements.
  • NEC recognizes that direct shutdown via BMS can serve as the battery disconnect, provided it de-energizes external conductors.
• Labeling & Identification:
• NEC requires clear labeling of ESS disconnects so that homeowners, AHJs, and first responders can quickly identify and operate them.

Practical Implications

• In residential installs, you’ll need an outside emergency shutdown switch that first responders can operate.
• For commercial/industrial installs, the disconnect must be readily accessible, lockable, and clearly marked.
• Integrated ESS units often meet these requirements internally, but installers must ensure field labeling and accessibility are compliant.

So my question is, does anyone know of any kind of remote control disconnect? Or a massive 48,000 Watt relay that doesn't humm horribly? The battery uses four 2/0 aluminum cables, two red and two black to connect to the inverter.

You already have it. Hook up a big red switch the the EG4 rapid shutdown port on the inverter. If the switch is opened, the inverter turns off the batteries. (As far as I know, EG4 is the only company that has this feature)

 

[albrittbrat]

Thank you so much!!! I will re-submit my application with this as the proposed solution and we'll see what they say. Hopefully takes less than a month to get an answer this time

And running wires from the ESD like this, you aren't concerned about it having connectivity issues if it's ~100 feet from the inverter to the disconnect and another 100 feet back to the inverter?

 

[Hedges]

Hopefully not too noise sensitive.
Use a twisted pair.

 

[FilterGuy]

And running wires from the ESD like this, you aren't concerned about it having connectivity issues if it's ~100 feet from the inverter to the disconnect and another 100 feet back to the inverter?

Nope. Not at all worried. The current on the wire is probably less than a milliamp. The voltage drop will be negligible if you use normal signal wire. Even if you used cat5 wire (24AWG) it would almost certainly not be an issue.

There is one gotcha an inspector might complain about. Since the wire goes into the wire box of the inverter that also has the 240V lines, they might insist on a 600V jacket on the signal wire. (Some inspectors get anal about it, others don't). Heard of one case where they had the expensive 600V jacketed wire inside the inverter and then spliced it to sprinkler wire once it was outside the inverter.

 

[FilterGuy]

Hopefully not too noise sensitive.
Use a twisted pair.

Twisted pair is always better, but it is an always-on signal driven by a power supply. It is very insensitive to external noise.

 

[FilterGuy]

BTW: The switch has to be 'normally closed'. This is a safety feature. If the wiring ever gets cut or damaged, you will know right away because the whole system will shut down. If it was a normally open circuit, you would not know the emergency disconnect feature is broken till you try to use it.

 

[FilterGuy]

BTW:

There are 3 different things that often get confused.

1) PV rapid shutdown (PV RSD).
PV RSD requires the panels get disconnected and alway entails electronics at the panels and a remote initiator. The initiator for this is required to be readily accessible to first responders (It has to be outside).

The Rapid Shutdown built into the 18Kpv meets the requirements of the NEC if Sunspec Compliant RSD receivers are installed with the panels.

2) Energy Storage System Emergency Disconnect.
This must disconnect the output of the system from the rest of the premise wiring. The initiator for this is required to be readily accessible to first responders (It has to be outside).

The Rapid Shutdown built into the 18Kpv meets the requirements of the NEC, but many jurisdictions require a big ugly knife switch on the AC out of the inverter ESS system.

3) Battery Disconnect.
The battery disconnect must disconnect all ungrounded conductors. (In almost all systems these days that is both positive and negative)
The disconnect can be built into the ESS or be within 10ft of the ESS or be remote if it is a lockable switch.
The built in battery breakers meet the code, but it sounds like you have an inspector demanding more.

The Rapid Shutdown built into the 18KPV will send a shutdown signal to EG4 batteries that cause the batteries to open their breakers. (I don't think other batteries support this function)

 

[Hedges]

SMA provides a silicone tube as extra insulation around twisted pair wires inside their inverters.
Could do that wherever the wires need to coexist with AC lines.

Twisted pair is always better, but it is an always-on signal driven by a power supply. It is very insensitive to external noise.

The driven signal of course is. What matters is the receiver, how it acts if it sees a brief coupled glitch. Slow response, which can simply be an RC delay, could make it immune.

Good that EG4 provided this feature, so installations can meet this code/safety requirement.

 

[Quattrohead]

Send this white paper to them, what they are asking for is against code.

https://eg4electronics.com/wp-content/uploads/2025/03/EG4-NEC-Code-Compliance-for-AC-DC-Disconnects.pdf

 

[albrittbrat]

So much info! I really appreciate it!
I'm attaching my pre-talking-to-you-guys and post '' one-line diagrams (removed personal info from these vs the ones sent to utility)
On the pre one that I submitted, they came back with 'There must be a lockable, utility accessible red-lever disconnect after the meter base. All energy storage systems (ESS) must include a lockable, utility accessible red-lever disconnect located near the meter base'

So I'm hoping that my corrections will meet these requirements.
I'm looking at a Eaton DH364URK 200A 600V 3R heavy duty non-fused safety switch for the mains disconnect and an Eaton DH261URK 30A 600V 3R heavy duty non-fused safety switch for the 18kPV RSD system (obligatory ugly scissor switches)

I'll definitely include a link to the white paper in the diagram I re-submit as well and just be like 'please see this white paper for explanation of how RSD disconnect in this inverter meets all NEC code requirements for the system'.

Cat6 cable would definitely be the easiest for me as I have a large chunk of a spool sitting in the garage, and I'm not above splicing it where they can't see if they get all uppity about it.

 

[RDuke]

I forget where I bought it from, but I used cable marked TC-ER-JP for my ESS shutdown button because the stuff is 600V rated and is approved for joist pull so it can be run through walls and attic just like romex. It is also rated for direct burial to control things like a generator. Of course my inspector did not ask to check it, but I was not taking any chances. If you do use ethernet cable, I would use industrial ethernet that is 600V rated, not because it needs to be for the application to work, but because you want to be careful about having wires inside your inverter equipment that an inspector might call out for not having the right voltage rating. My guess it is just a relay contact using low voltage, but you would have to put a meter on it to verify. It would not be a signal level thing so noise is not likely to be an issue on that cable. The TC-ER-JP cable I used has 4 conductors, but I only used two of the 18 gauge wires. The button I got has a key lock on it, so if you press it, you need a key to pop it open again.

I was kind of surprised I could not tell what code Illinois is using. The 2023 code has a lot of updates regarding ESS in 706 and they make it pretty clear the intent is to disconnect the OUTPUT of the ESS from the premise wiring and can be internal to the ESS itself. It does not mandate how. Regardless of how it is disconnected, a fully charged ESS is still a source of stored power no matter how it is disconnected. The point is to disconnect it from the house wiring for firefighters protection. Oh, and don't forget your labels on that button. It has to say "Energy Storage System Disconnect" at least in the latest code. It makes it kind of difficult not knowing for sure which code they are using for reference. Some of the labeling requirements in 2023 are weird because it says you need a number of things on the label, then it goes on to say but in 1 and 2 family dwellings you do not need those extra parameters on the label. The best I could figure out is that you need the label saying what the ESS output voltages are. You can look at pvlabels.com and just do a search for ESS to find the options.

 

[pss5272]

Based on your location I'm guessing amren is your POCO. There interconnection document found here

https://www.ameren.com/-/media/illi...terconnection-policy-public-facing-guide.ashx section

5.3 is the relevant section.

5.3. A generator disconnect switch must be installed by the customer that can safely isolate allparallel generation or energy storage (DG or ESS) from the distribution. This switch must be thefirst device on the generation side of the POI and must comply with the guidance provided inthe Generation Customer Checklist provided during the application process. A separatedisconnect switch for an ESS may be required for systems that incorporate both DG and ESS. This switch must be lockable, readily accessible to utility, gang operated (if three‐phase), andhave a visible indicator of the switch's position. If the voltage at the POI is greater than 1000V,the switch must also have a visible air gap when in the open position. This switch is requiredper the 2020 NEC (sections 480.7(B), 690.12(C), 694.22(C)(1), and 706.15(A)) to allow utilitypersonnel, the customer, or emergency first responders to isolate DER facilities formaintenance, reliability, or safety concerns. In cases where the generator disconnect switch islocked closed or locked behind a gate, a lock box will be provided by Ameren Illinois andinstalled by the customer at an accessible location to Ameren Illinois personnel. The lock boxwill contain a key to access and operate the generator disconnect switch and will be lockedclosed with an Ameren Illinois lock.

According to that document a simple disconnect switch should suffice as long as you do not have 3 phase power or POI above 1000V. I would recommend using something like the attached. it should meet all the requirements. A red lever disconnect so to speak should likely not be required.

Don't know the exact communication from your POCO/town but they should have actually denied your first one-line due to code requirements for RSD. NEC 690.12 requires the RSD initiator to be readily accessible on the exterior of the building. There specific requirement for a "red lever" disconnect seems to be the only overreach.

 

[sumpower]

Send this white paper to them, what they are asking for is against code.

https://eg4electronics.com/wp-content/uploads/2025/03/EG4-NEC-Code-Compliance-for-AC-DC-Disconnects.pdf

That was worth the read! Thanks for the link.