EG4 GridBOSS Microgrid Interconnect Device (MID)

Description

EG4’s GridBOSS is a MID (Microgrid Interconnect Device), also known as a gateway, for connecting, operating and organizing power systems. It serves as a centralized hub that integrates grid power, hybrid inverters, generators, and smart loads. 

This is intended for use with EG4 hybrid inverters such as the 18kPV, 12kPV, FlexBOSS21, and the FlexBOSS18. Hybrid inverters operate bi-directionally, managing and blending power from solar panels, batteries, and AC sources like grid or generator power.

The GridBOSS v3.1 allows users to choose which breakers they wish to install. This version does not include any breakers with the unit, and most ports have the option of using either BSB or Eaton breakers.

Operation

When the GridBOSS detects grid power is lost, it immediately opens the grid transfer switch,  isolating the system from the grid and preventing power from flowing back. It switches connected inverters into off-grid mode to keep powering critical loads without interruption. When grid power is restored, the GridBOSS automatically re-connects to the grid, resuming normal operation. 

For extended outages, the GridBOSS provides a generator start signal (two-wire start) and accepts generator power through the 125A smart load port. After a programmable warm-up period, the transfer switch engages, providing generator power to loads and the hybrid inverters for battery charging. After the batteries are replenished, the generator is disconnected and shut off after a cool-down delay.

Applications

The GridBOSS is a service gateway for the entire system. It is service rated with a 22kAIC rating. With an added main circuit breaker, a utility meter can feed the GridBOSS directly. This unit includes a manual bypass switch, allowing grid power to directly power critical loads, bypassing the energy storage system. 

Many homes in the US are provided with a 200A service. The GridBOSS’s built-in 200A transfer switch compliments inverters like the FlexBOSS21 that only has 90A passthrough. This segregated approach reduces wire costs and installation complexity and simplifies the permitting process. 

Inverters with separated MID arrangements have more flexibility than traditional system installations. Smaller wire between the inverter and MID is necessary. Therefore, it extends the distance between GridBOSS and the system peripherals to up to 300ft away without making wiring impractical. 

Compared to hybrid inverters with built-in transfer switches, the cost savings is greatly improved on multi-inverter installations. A GridBOSS eliminates additional external components like combiner boxes, disconnects, splices, and multiple runs of heavy duty wire. 

The MID is designed to support up to three hybrid inverters, and each port is rated up to 90A. This means the GridBOSS supports up to three FlexBOSS21 inverters since they are each rated for 90A passthrough.

Features

GridBOSS is engineered with four programmable smart load ports, which support AC coupled inverters and smart load management up to 125A. The four ports (125A/80A/60A/60A) are an ideal solution for offsetting grid usage during peak generation hours. 

EG4’s web monitoring platform facilitates firmware updates, provides remote setting changes, and displays data logs. It also allows system management remotely via their monitoring app. 

The GridBOSS has the ability to communicate with a remote RSD initiator, which triggers the entire system to enter rapid shutdown. It de-energizes the entire energy storage system which satisfies NEC code requirements for external ESS disconnects.

This is a NEMA 3R outdoor-rated unit which can be used inside or outside, even in areas with heavy rain or dust. It operates at a wide range of temperatures, from -40°F to 113°F.  The GridBOSS is certified to UL 1741, UL 67, and UL 869A standards (when used with copper wire).