Appendix D: Install External DC Isolation

To facilitate safe maintenance and testing, some regional electrical codes may require a means of isolating the PV array be provided adjacent to a PV inverter. The integrated DC isolator in Powerwall 3 provides a means to switch-off the feed from the PV array, however the PV wires terminated within the Powerwall 3 remain live. To achieve full code compliance, it is necessary to provide a means of PV array isolation external to the Powerwall 3.

Installation Options

The following are options to make the installation compliant if the local electrical codes require a means of isolating the PV array:
  • The use of suitably rated plug and socket connectors (e.g. MC4) on the feed from the PV array. These can be installed directly into the PV array wires using a harness with connectors before they enter the Powerwall 3, or fitted to an external enclosure adjacent to the Powerwall 3 (e.g. where an enclosure needs to be installed for surge protection devices or fuses).
  • The use of a suitably rated DC isolator adjacent to the Powerwall 3.
In all cases, local codes should be carefully studied to ensure full compliance of the whole installation.

Installing Connectors (e.g. MC4) on an External Enclosure

If an external enclosure needs to be installed adjacent to the Powerwall 3 for surge protection devices or fuses, the connectors can be installed on the external enclosure.

To isolate the Powerwall 3 from the DC side, the Powerwall 3integrated DC isolator must be turned OFF and the connectors must be disconnected. The connectors also provide a convenient testing point for string tests.

Installing a Harness with Connectors (e.g. MC4) Directly into the PV Array Wires

If an external enclosure doesn't need to be installed, the connectors can be installed directly into the PV array wires using a harness with connectors.

To isolate the Powerwall 3 from the DC side, the Powerwall 3integrated DC isolator must be turned OFF and the connectors must be disconnected. The connectors also provide a convenient testing point for string tests.
Informational PurposesAn informational icon, calling your attention
Note
This option can cause cable management issues with a bundle of connectors.

Installing an External DC Isolator

If the connectors are not a suitable option for any reason, an external DC isolator can be installed adjacent to the Powerwall 3.

To isolate the Powerwall 3 from the DC side, the external DC isolator must be turned OFF. This option does not require connectors (e.g. MC4), but using such connectors may simplify string testing.