Solar Energy Customer Program:
Technical Requirements - Small Systems
The PNM Solar Energy Incentive Program has the following technical requirements for small systems (up to 10 kW):
System type and size
- System generating electricity using PV or solar thermal technologies with an inverter VAC of 10 kW or less.
- For purposes of the technical requirements it is referred to as a "small system".
- Contact PNM if your small system will have battery or generator backup capability.
- The system will require special approval if it will include battery backup or any type of fossil fuel backup generation.
Interconnection
- Your small system must be designed to connect to the PNM electric grid and – following all inspections and approvals – be interconnected to the grid.
- The system must interconnect by means of a UL 1741-compliant inverter.
- Most 120V and 240V inverters will require a standard 4 terminal (4 jaw) meter base to receive a standard form 1S or 2S meter.
- For inverters with different voltage outputs, contact PNM.
Learn more about the regulations that apply to customer-owned generation and interconnection to the PNM power grid
Customer disconnect switch
- PNM requires that a lockable load-break disconnect switch be installed between the output of the inverter and the point of interconnection.
- Utility personnel must be able to access the switch.
- This switch, referred to as the customer generation AC disconnect switch, must provide a verifiable, visible air gap between the inverter and the point of interconnection.
- Be sure to confirm with your installer that opening the customer generation AC disconnect switch will not cause you to be without power from PNM.
- Circuit breakers and inverter software modes do not meet the disconnect switch requirement.
Required diagrams and signage
Review the Customer Owned Generating Systems section in the Electric Service Guide for examples of required diagrams.
2012 Electric Service Guide (.pdf)
One-line diagram, site map and safety signage requirements
- Diagrams and signs must be weatherproof.
- The one-line diagram should not be placed on the inverter. The inverter could be located on a pole, in the garage or near a ground-mounted system and may be separated from the customer generation AC disconnect and / or REC meter, if present.
Placement of the one-line diagram, site map and safety signage depend on where the REC meter and billing meter (also known as the net meter) are located.
See detailed diagrams of the different scenarios (.ppt)
Scenario 1
REC meter and billing meter are grouped together and in plain line of sight.
- A one-line diagram, or a sketch of the system, is placed at PNM billing meter.
- A sign must be placed on the customer generation AC disconnect switch, which says: "UTILITY SAFETY DISCONNECT USED TO ISOLATE FROM CUSTOMER GENERATION".
Scenario 2
REC meter and billing meter are installed next to the same building, but not grouped together and not in plain line of sight, or if the PNM billing meter cannot be seen from the customer generation AC disconnect switch.
- Site map is placed on the PNM billing meter (also known as the net meter).
- One-line diagram is placed on the REC meter.
- A sign must be placed on the PNM billing meter which says: "Warning Customer-Owned Generator Connected. See drawing for Disconnect Location".
- A sign must be placed on the customer generation AC disconnect switch, which says: "UTILITY SAFETY DISCONNECT USED TO ISOLATE FROM CUSTOMER GENERATION".
Scenario 3
REC meter and net meter are installed next to different buildings, are not grouped together and not in plain line of sight. For example, the PNM billing meter is installed next to the house and the REC meter is installed next to a detached garage.
- Site map is placed on the PNM billing meter (also known as the net meter).
- One-line diagram is placed on the REC meter.
- A sign must be placed on the PNM billing meter which says: "Warning Customer-Owned Generator Connected. See drawing for Disconnect Location".
- A sign must be placed on the customer generation AC disconnect switch, which says: "UTILITY SAFETY DISCONNECT USED TO ISOLATE FROM CUSTOMER GENERATION".
Scenario 4
REC meter and billing meter are grouped together and in plain line of sight, and the system has more than one AC disconnect.
- One-line diagram is placed at the REC meter.
- A sign must be placed on the customer generation AC disconnect switch next to the REC meter which says: "UTILITY SAFETY DISCONNECT USED TO ISOLATE FROM CUSTOMER GENERATION".
Permanent one-line diagram label and storage examples
View a drawing-tube example for weatherproof diagram
storage
View a mail slot-style example for weatherproof
diagram storage
View a permanent label example for
weatherproof diagram display
REC meter (for REC incentive participants)
- If you choose to participate in the REC purchase program, your system must have a REC meter.
- You or your contractor must install the meter base for your system’s REC meter; PNM installs the meter.
View a meter base wiring diagram
- The REC meter must be electrically connected at the output of your PV system inverter before any loads, and must be physically located near your PNM electric billing meter.
Contact PNM if you still have questions
Return to the program participation steps
