Grid Detection Circuit Installation Overview
Lumin's Grid Detection Circuit (GDC) must be installed in order for Smart Power Mode/Off-Grid Mode to function. Until the GDC is energized for the first time, Smart Power Mode/Off-Grid Mode will not appear as an available feature in the Lumin mobile app or web portal.
The GDC consists of two AWG #12 wires, one black and one white, that extend out of the flexible conduit that comes pre-installed with the Lumin Smart Panel. These two wires are both labeled GRID. The neutral white wire should be landed on the closest neutral bar to the black wire's point of connection to the site wiring.
The GDC functions by detecting voltage in a portion of the electrical system that is on the line/utility side of an automatic transfer switch or microgrid interconnection device (e.g., Tesla Gateway). The GDC includes a relay that sends a signal to the Lumin Smart Panel when grid voltage is lost, activating Smart Power Mode/Off-Grid Mode. Do not connect the GDC to any portion of the system backed up by batteries or other on-site backup power.
Note that only one GDC is required per installation location. This circuit can be branched off to each Lumin Smart Panel at the location so that they all get the same signal regarding the presence or absence of the grid.
One method of installation is simply to locate a load center that is not backed up by a battery and thus will lose power in the case of an outage. If such a load center is present, the GDC black wire can be landed on its own circuit breaker or pigtailed to an existing circuit where allowed by code. There is virtually no current in the GDC circuit, so it may be connected to any breaker that protects the wire (AWG #12).
When non-backed up circuit breakers are not available, the black wire may also be terminated by tapping non-backed-up feeder conductors that are on the load side of the service disconnect but outside of the Energy Storage System. Ensure proper and code-compliant overcurrent protection is applied when making such a connection.
When no connection can be made on the load side of the service disconnect, the GDC black wire may be connected to a service entrance conductor. Note that this procedure is inherently dangerous and must only be done by qualified personnel. If you are unsure about proper methods for code-compliant supply-side connections for energy management systems, do not proceed.
Grid Detection Circuit Installation Example
Note: This is an example from the field. Confirm local requirements for supply-side connections and service-rated overcurrent protection/disconnects with your local Authority Having Jurisdiction.
1. Locate a supply-side connection point inside an enclosure.
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2. The connection to a service entrance conductor is made with an insulated piercing connector (IPC).
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The National Electric Code requires that supply-side connections to service wiring use a minimum wire gauge of AWG 6. When connected to the service entrance conductors, this connection must feature a service-rated disconnect so that the GDC can be safely de-energized. It is also necessary to protect the supply-side connected GDC with an overcurrent protection device, which can be integral to the service-rated disconnect or can be a separate device located immediately on the load side of it. A typical approach is to make the connection with a short length of #6 and run that to a service-rated fused disconnect with a fuse appropriately sized to protect the smallest conductors in the GDC. Lumin GDC wiring is 12 AWG and would typically be protected with an OCPD with a rating of no more than 20 amperes. As there should never be any current on the GDC, smaller OCP ratings are acceptable and will not trip/blow under normal conditions.
Only once the GDC is successfully installed will Smart Power Mode/Off-Grid Mode become available in the Lumin mobile app and web browser.