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NG - National Grid (MA)

Massachusetts Utility Interconnection & net metering rules
Net Metering Allowed1
NEM TypeMonthly
Supply Side Taps Allowed1
Line Taps Allowed1
Load Taps Allowed1
AC Disconnect RequiredYes

Net metering & export

Net Metering Allowed
1
NEM Type
Monthly
TOU Utility
0
Post Solar Billing Method
Net Metering
Solar Export Type
N/A
Net Excess Generation Notes
  • Excess generation at the end of each month is credited at the applicable retail electricity rate and rolled forward to future bills as a dollar credit. This credit rolls forward indefinitely to future bills but cannot be "cashed out".
Rebates Offered
1
Deregulated
1
Allows Standby
1

Interconnection & taps

Approval Req To Install
Yes
Interconnection Level
3
Supply Side Taps Allowed
1
Line Taps Allowed
1
Load Taps Allowed
1
Tap Criteria
  • Cannot be in same compartment as utility meter.
  • (2) AC disconnects are required. Inv > Non-fused Disco (outside) > Fused Disco (inside, if necessary) > POI
Automatic Transformer Upgrade Size
0
Meter Aggregation Allowed
1

System size & offset

System Size Restrictions
25
System Size Restriction Type
AC kW
System Size Battery Included
0
System Size Includes Existing Systems
0
Offset Type
No Restrictions
Offset Value
0
Offset Calculation Period
0
Industry Standard Watts Sqft
2
Utility Specific Adjustments

Please keep system size under 15 kW AC whenever possible.

For example:

  • Please use mix of 7.6KVA and 5.7KVA to be under 15KW AC rather than using two 7.6KVAs. This will avoid Level 2 application and reduce approval times.

Curtailment Requirements

  • National Grid allows system curtailment to avoid transformer upgrades and group studies
  • Approved curtailment systems: Tesla Gateway, Enphase IQ, and Generac PWRcell
  • Update all documents to show the system curtailed to 15 kW AC export
  • Add a label showing aggregate AC kW/kVA ratings
  • Show both total system size and curtailed system size
  • Show internal DB protective device settings for inverters (see Tables 7.6.11.1-1 & 7.6.11.1-2, Page 33 in ESB 756)
  • Provide a curtailment letter on manufacturer letterhead if the system is larger than the proposed export, including the model number of the Smart Hub/Gateway and the proposed system output (curtailed value)
Inverter Oversize Restrictions
1
System Size Justification
Load Justification
System Offset Notes


Metering & disconnect

Production Meter Required
Situational
Production Meter Criteria

Production Meter (SMART meter)

  • Required for: Cash, Loan, Aura, Aura+
  • Not required for: Lease projects
  • Wire inverter on bottom side and utility on top side
  • Only 1 production meter per project
  • Second meter allowed only if 12 months have passed since existing system PTO
Production Meter Position
Inv-Disco-PM-POI
Production Meter Labeling
Production Meter
AC Disconnect Required
Yes
AC Disconnect Labeling
Accessible and Lockable AC Disconnect
Meter Spot Required
0
Meter Spot Process
  • Some AHJs do not allow PV and MPU on a single utility work order #. Please request separate work order #s for each type of work.
Allowed Meter Adapter
None

Plans & docs

Electric Service Reqs
  • Meter relocation is required if the utility meter is located indoors or inside any cabinet
  • Single Meter - Center of meter must be between 30 and 60 inches
  • Multi Meter - Center of meter must be between 36 and 60 inches
Placards
  • Unit designation labels are required for the meter sockets at the premise (Example; Unit 1, Apt 1, etc)
Electrical Stamp Required
1
Equipment Approvals
Other
Meter Num Req SLD 3LD
0
ESID Num Req SLD 3LD
0
Site Plan Notes


Label Page Notes


Cover Page Notes


Electrical Diagram Notes

Battery [STORAGE CHARGING CAPABILITY: GENERATION ONLY STORAGE DISCHARGING CHARACTERISTICS: ON-SITE LOAD ONLY]

Website
link
Phone
(800) 322-3223

Other details

Restrict Inspection
1
Revision Required
1
Mod Swap Requires Planset
1
Address ID
2231602
Express Planset Eligible
Yes
Compiled from public records, 2026. Tariffs and interconnection rules change; verify with NG - National Grid (MA) before you rely on this. The useful move: if an installer says you need a main panel upgrade, ask how these tap and interconnection policies were considered first.