Grid Jarvis · Blog

Meter cabinet first, heat pump second: how to check it before the first visit

The heat pump is already on its base, and the electrician has come to connect it. But the cellar of this 1970s single-family house still has an old meter board. Adding the heat pump changes the customer installation, and as a rule a board like this cannot stay in service after that. There is no room for a smart meter gateway and control box (Steuerbox) anyway. Nothing gets connected that day.

The customer asks why nobody saw this earlier. The meter cabinet turns into a separate job, and the trip is wasted.

In Germany, 2026 brought a new edition of VDE-AR-N 4100, the rule for connecting customer installations to the low-voltage grid. It also brought a new model text for the TAB, the grid operators' technical connection conditions. This post looks at the photos and data you need before the first visit to judge the meter position (Zählerplatz), and the order in which to plan the work (as of September 2026).

What applies to the meter position in 2026

VDE-AR-N 4100:2026-04 was published on 6 March 2026 and replaces the 2019-04 edition and its amendments. VDE FNN, the VDE's grid technology forum, has listed it as valid since then, but has not publicly named a start date or a transition period. A few grid operators give 1 April 2026 as the start date and a twelve-month transition period.

Sources disagree on how long the old edition may still be used. EAM Netz allows it until 31 March 2027, but only for a whole installation, without mixing old and new. Elsewhere, the transition is said to apply only to projects already being planned or built on 1 April 2026. What counts is what your grid operator accepts. Note on every job which edition you are building to.

According to the German Association of Energy and Water Industries (BDEW), more than 90% of distribution system operators base their TAB on its model text. BDEW published TAB Niederspannung 2026 on 31 July 2026. It only applies once your grid operator publicly announces it and puts it into force. Under § 19 of the Energy Industry Act (Energiewirtschaftsgesetz, EnWG), grid operators must flag their own additions and give reasons for them.

What § 14a EnWG and § 9 EEG mean for your planning

The rules under § 14a EnWG and the determinations (Festlegungen) of the Federal Network Agency (Bundesnetzagentur, BNetzA) apply to controllable consumption devices (steuerbare Verbrauchseinrichtungen), such as heat pumps and private wallboxes above 4.2 kW, put into operation on or after 1 January 2024. The grid operator may not refuse or delay their connection because the grid might be overloaded. For your company, this means:

  • Register first. The grid operator needs a registration for every controllable device before it goes into operation. This follows from § 19(2) of the Low-Voltage Connection Ordinance (Niederspannungsanschlussverordnung, NAV) and section 9.2.1 of TAB 2026. State in the registration whether the device is controlled directly or through an energy management system. The BDEW model text requires no approval for § 14a heat pumps. Wallboxes of any power must be reported in advance. If the wallboxes' total rated power per installation is above 12 kVA, as with two 11 kW wallboxes, the NAV requires prior approval. That applies even where the model text does not ask for it for § 14a wallboxes that do not feed power back into the grid. Plan on needing approval unless your grid operator waives it in writing.
  • Provide the control interface yourself, as part of the customer installation, in the installation-side connection space. The default is digital control based on VDE-AR-E 2829-6-1, via an RJ45 socket as specified in VDE-AR-N 4100 and a data cable of at least Cat 5. A terminal strip for relay control is allowed only for a transition period and under certain conditions. If you use one, run a Cat 5 cable or an empty conduit alongside it.
  • Get the order to the metering point operator (Messstellenbetreiber) early, for a smart metering system and control device (Steuerungseinrichtung, in practice the control box). The customer places the order, or you do with their authorization. Placing it already meets the customer's obligations (§ 14a(4) sentence 3 EnWG). According to the BNetzA, fitting the equipment may still be delayed (as of September 2026). If a heat pump's subsidy application to KfW, Germany's federal development bank, was submitted on or after 21 July 2026, the order is a condition for funding. Where there is no § 14a obligation, ordering the smart metering system alone is enough.

For PV systems, § 9(1) of the Renewable Energy Sources Act (Erneuerbare-Energien-Gesetz, EEG) requires the installation behind the house connection fuse to be made ready for a metering system and control device. Plug-in solar devices up to 2 kW are exempt. Until the metering system and control device are installed and tested, new PV systems under 100 kW that receive a feed-in tariff or tenant electricity premium (Mieterstromzuschlag) may feed in at most 60% of their power (§ 9(2) sentence 1 nos. 2 and 3 EEG). At 25 kW and above, the grid operator must also be able to control the feed-in remotely. The government bill for EEG 2027 (Bundestag printed paper 21/7867) would permanently cap new PV systems on buildings under 100 kW at 50%, regardless of the metering system. It had not been passed by 17 September 2026. So here too, the meter position check comes before installation.

Photos and data before the first visit

Good photos often let you estimate whether a meter position will do. The customer sends some with the request, with the door open but all covers and seals in place. Your qualified electrician (Elektrofachkraft) photographs what lies behind them at a short site visit. In our view, a fixed checklist works well.

From the customer, with covers on:

  • Overall view of the meter cabinet, closed and with the door open.
  • Rating plate or standard marking, to identify the cabinet type.
  • Meter fields: occupied or free, eHZ plug-in mounting (for electronic household meters) or 3-point mounting.
  • Space for smart meter gateway and control box, for example a free APZ field (Abschlusspunkt Zählerplatz, for communication equipment) or a free distribution field.
  • House connection box, closed, with the fuse rating if legible.
  • Surroundings: the room (cellar, stairwell, bathroom, flat in an apartment building) and the free space in front.
  • Mobile reception at the meter position, as a phone screenshot.
  • Cable route to where the heat pump or wallbox will go.

At the site visit, by your qualified electrician:

  • Grid-side connection space: isolating device or NH fuses (low-voltage high-breaking-capacity fuses).
  • Installation-side connection space: height and main switch, plus RJ45 socket or terminal strip.
  • Close-up of the wiring: cross-section (at least 10 mm²) and signs of overheating.

Plus details no photo shows:

  • Grid operator and the TAB version in force (on VNBdigital, the grid operators' joint online platform), plus metering point operator and meter number.
  • Whether a smart metering system is already installed, or an old § 14a arrangement from before 2024 exists, such as a separate heat pump meter.
  • Earthing system (for example TN-C-S or TT), and whether the connection is single-phase or three-phase.
  • Planned devices with rated power (heat pump including immersion heater) and type of control, plus PV and storage.
  • Connection customer (Anschlussnehmer, usually the property owner) and who must consent, for example the owners' association (WEG).
  • Any KfW funding in progress.

The photos do not replace the check on site. The FNN note on meter positions in existing installations ("Zählerplätze in Bestandsanlagen") says a qualified electrician must check the meter position before any change, and the TAB make the installer (Errichter) responsible for the decision. The photos show which appointment comes next and what belongs in the quote.

When the existing meter position is good enough

The basic rule under VDE-AR-N 4100 and the TAB: what stays unchanged need not be adapted, as long as operation is safe. So not every old meter board has to go. Exceptions can arise, for example, from § 9 EEG or the metering point operator's requirements. But if you change the customer installation, it is your job as the installer to check whether the meter position still fits. The FNN note names typical triggers, for example higher power and a switch to three-phase. A continuous load such as a heat pump counts too, as does an installation that will start feeding power into the grid.

For each type of meter position, Annex E of the BDEW model text TAB 2026 recommends whether it can stay in use after the change. Roughly:

  • Meter board to DIN 43853 or TGL (East German standard), including Z6 cabinets: no. Plan the new meter cabinet ahead of the heat pump or wallbox installation.
  • Cabinet to DIN 43870: yes, if there is an isolating device in the installation-side connection space or an NH fuse in the grid-side one, and the wiring is flexible with a cross-section of at least 10 mm². The grid operator's requirements and the FNN note also apply. Schedule an inspection before the quote.
  • Cabinet to DIN VDE 0603 with isolating device: yes, subject to the FNN note. Check the space for the smart meter gateway and control box all the same.
  • Cabinet to VDE-AR-N 4100: yes. According to EAM Netz, the 2026-04 edition also allows the APZ field to be used for the control box.

The grid operator's additions and the metering point operator's minimum technical requirements (Technische Mindestanforderungen, TMA) always take precedence.

Who waits for whom

The device cannot go into operation until it is registered and, where needed, approved by the grid operator. The control box waits for a finished meter position. As a rule, the device does not wait for the control box, because the order to the metering point operator is enough. When you register, ask whether your grid operator handles any of this differently. The sequence:

  1. Pre-check and quote, with the meter cabinet as a separate line item.
  2. Registration with the grid operator, with the type of control for § 14a devices. If the wallboxes together exceed 12 kVA, the grid operator must respond within two months under § 19(2) NAV. For other devices that need approval, the NAV sets no deadline. If the house connection is too small, apply for the upgrade at the same time.
  3. Place the order with the metering point operator, at the same time as the registration.
  4. Rebuild or upgrade the meter cabinet. Break seals only with the consent of whoever applied them. Submit the completion notice (installer's confirmation, Errichterbestätigung) to the grid operator. The metering point operator installs or relocates the meters. The details depend on your grid operator's procedure. With some grid operators, the meter appointment is only booked once the completion notice is in. Ask whether the metering point operator can install the smart metering system and control box at that appointment. That saves a visit.
  5. Install the device and lay the data cable to the interface.
  6. Commissioning (Inbetriebsetzung) by your company, as an installer registered with the grid operator (eingetragenes Installationsunternehmen).
  7. Control box, if not done yet: the metering point operator installs it and connects it to the interface.

In our view, it pays to agree the installation date with the metering point operator only once everything at the meter position is ready:

  • the field for the control box
  • the interface
  • the supply from the unmetered section
  • an empty conduit for the antenna, if reception is poor

In the appointment confirmation to the metering point operator and the customer, state what is already in place.

Raise the costs early

The connection customer pays for the meter position and the installation behind the house connection fuse (§ 22 NAV, § 13 NAV), not the grid operator or metering point operator. The grid operator may charge for upgrading the house connection (§ 9 NAV), but it may only charge a construction cost contribution (Baukostenzuschuss) for the share of power above 30 kW (§ 11 NAV).

Where the default metering point operator (grundzuständiger Messstellenbetreiber) runs the meter, a metering point with a § 14a agreement costs the connection user (Anschlussnutzer), as a rule, at most €50 a year including VAT. The control device costs the connection customer at most another €50. Both limits are set in § 30 of the Metering Point Operation Act (Messstellenbetriebsgesetz, MsbG). For high consumption or a larger PV system, a higher limit applies. In return, the grid fee is reduced. According to the BNetzA, the flat-rate reduction under Module 1 was €110 to €190 a year in 2023, depending on the grid area.

If the customer asks for installation ahead of the metering point operator's own schedule, a one-off fee may be added. § 35 MsbG presumes up to €100 including VAT to be reasonable. For subsidized heat pumps, the KfW information sheet (version 11.0) treats the installation fee as eligible. It does not mention the meter cabinet explicitly. In our view, it is better not to promise funding for it until KfW has confirmed it.

List the meter cabinet as a separate line item in the quote. After the photos, make it a contingency item priced as a range from your past jobs. After the on-site check, replace it with a fixed amount. The reason for the customer: when an installation is extended, the meter position must be checked under the connection conditions and adapted if needed. And without a suitable meter position, the metering point operator cannot install the metering system and control box either. Say this at first contact, and you are explaining a line in the quote. Say it on installation day, and you are explaining a delay.

How Jarvis helps

Jarvis plans your jobs down to each technician's daily route, and agrees the site visit and the installation appointment with the customer by phone or SMS. Jarvis only schedules the installation appointment once the work order for the meter cabinet is complete.

In the Jarvis app, your technicians use a report form for each order type, even offline. The meter cabinet check can be an order type of its own, with a form that asks for the required photos from the list above. Every installation photo is checked by AI on site, and the technician gets feedback right away. Your qualified electrician still decides whether the meter position is good enough.

Bring the last job that got stuck at the meter cabinet, and we will run it through Jarvis together. Book a 15-minute walkthrough.

This article is not legal or funding advice (as of September 2026). What counts is the text of the standard and your grid operator's TAB. Your metering point operator's TMA count too, as do the funding conditions in force at the time of your application.

By Valter Pasanen, Founder, Grid Jarvis. Published 2026-09-17.