Site Metering

Site meters show the overall power flow to/from a site from the Grid’s perspective, i.e. the Grid is treated as the source of power and the home is a consumer of that power. Site meter(s) must be installed upstream of all solar production, Powerwalls, and home loads. There are three options for performing Site metering; multiple Site meters can be installed together where needed, but their sum should capture all of the power flows from load, solar, and Powerwall(s).

Backup Switch (Meter Z) has two integrated CTs which can measure either all of the Site power flow (when Backup Switch is installed behind the utility meter), or a portion of the overall Site power flow (when Backup Switch is installed in a second meter socket).
Gateway 3 (Meter Z) has two integrated CTs which can measure either all of the Site power flow (like when Gateway 3 is the main service disconnect), or a portion of the overall Site power flow (like on partial home backup).
Backup Gateway 2 has two built-in meters.
- Internal Primary Meter (Meter X) has two integrated CTs which can measure either all of the Site power flow (like when Backup Gateway 2 is the main service disconnect), or a portion of the overall Site power flow (like on partial home backup).
- Internal Secondary Meter (Meter Y) has three internal CT connections. When loads or solar are left upstream of Backup Gateway 2, Tesla 100 A CTs can be installed on those non-backup loads and connected to Meter Y.
For systems with partial home backup, a Remote Energy Meter may be required and can be installed in the non-backup panel, with CTs installed to measure the non-backup loads or the entire Site measurement.
- The Tesla Remote Energy Meter has three CT connections (CT4 functionality will be available at a future date) and can only be installed with Tesla 200 A CTs.
- The Neurio Remote Energy Meter has four CT connections and can only be installed with Neurio CTs.
  Note
  Neurio Remote Energy Meters are not compatible with Powerwall 3.
Note
When the Remote Energy Meter CTs are capturing the entire Site measurement, the Internal Primary Meter X CTs are configured as None to avoid counting Site twice.

Site Metering for Powerwall Systems with Whole Home Backup

For systems with whole home backup (all loads and solar are downstream of the Islanding Contactor), Backup Gateway 2 (Meter X), Backup Switch, or Gateway 3 performs all Site metering.

Note

See Meter and CT Compatibility to learn which CTs are compatible with each meter type.

Figure 1. Whole Home Backup Configuration with Backup Switch Performing Site Metering

Figure 2. Whole Home Backup Configuration with Gateway 3 Performing Site Metering

Site Metering for Powerwall Systems with Partial Home Backup

For systems with partial home backup (some loads and/or solar are upstream of Backup Gateway 2 / Backup Switch / Gateway 3), there are three primary options to monitor the non-backup loads:

Backup Gateway 2 only: Connect the non-backup panel to the Backup Gateway 2 Non-Backup lugs. Because the Non-Backup lugs are downstream of Meter X, Meter X monitors those loads.
Backup Gateway 2 only: If the non-backup panel is upstream and within 330 ft (100 m) of Backup Gateway 2, and the non-backup loads are less than 100A, install Tesla 100 A CTs connected to Meter Y to monitor those loads. Tesla 100 A CTs can be extended using the following options:
- Tesla 100 A CT Extension (Tesla P/N 1467274-00-x), 11 ft (3.3 m) for a total length of 15 ft (4.5 m)
  Note
  CT extensions cannot be combined - only use a single CT extension.
- Splicing 20 AWG (0.5 mm²) or larger twisted pair conductors for a total maximum length of 330 ft (100 m)
In the example below, Meter X monitors all backup loads and Meter Y monitors non-backup loads.
If the non-backup panel is upstream and greater than 330 ft (100 m) from the Site Controller, or if the non-backup loads are greater than 100A, install a Remote Energy Meter and CTs to monitor Site:
- Tesla Remote Energy Meter is compatible with Powerwall 3, Controller Powerwall+, and Backup Gateway 2, and its CTs can be extended up to 16.4 ft (5 m) using a Tesla 200 A CT Extension (Tesla P/N 2060713-xx-y).
- Neurio Remote Energy Meter is compatible with Controller Powerwall+ and Backup Gateway 2, and its CTs can be extended up to 15 ft (4.5 m) using a Neurio CT Extension kit (Tesla P/N 1622289-xx-y).
Figure 3. Powerwall+ with Backup Gateway 2 in Partial Home Backup Configuration
Figure 4. Powerwall+ with Backup Switch in Second Meter Socket (Partial Home Backup Configuration)
Figure 5. Powerwall 3 with Gateway 3 in Partial Home Backup Configuration
Note
In these configurations, Meter X / Meter Z is configured as None as the Remote Energy Meter is monitoring all Site loads (backup and non-backup).
Note
Neurio Remote Energy Meters are not compatible with Powerwall 3; Tesla Remote Energy Meter must be used with Powerwall 3.

Site Metering for Solar-Only Systems

Note

If the Tesla Solar Inverter is installed with a Powerwall system, the Powerwall system performs Site metering. When commissioning the Tesla Solar Inverter(s), do not configure any CTs as Site.

For Solar Inverter systems with no Powerwalls, Neurio Remote Energy Meters are the only option for Site metering, as Backup Switch / Backup Gateway 2 / Gateway 3 are only installed with Powerwall.

When Solar Inverter is connected supply-side, Site CTs can be installed in two locations so that their combined measurements capture the entire Site measurement:

(2x) CTs are installed upstream of the main electrical panel with labels facing toward the grid (source)
(2x) CTs are installed on the output circuit(s) of the Solar Inverter(s) with labels facing toward the grid (source)