Ac Circuit Breaker Requirements; Grounding Electrode Conductor (Get); Lightning And Surge Protection; Multiple Inverters - Delta M Series Operation And Installation Manual

4.3

AC circuit breaker requirements

A dedicated circuit breaker in the building circuit panel is required for each Delta M series inver-
ter that is installed. There should be a circuit breaker or fuse to protect each AC line, L1 and L2.
The circuit breaker should be able to handle the rated maximum output voltage and current of the
inverter. Please refer to the table below to determine the appropriate circuit breaker size to avoid
potential fire hazards. The National Electrical Code (NEC), ANSI/NFPA 70 or applicable local elec-
trical codes must be folllowed when determining maximum branch-circuit over-current protection
requirements.
Inverter model
M4 -TL -US
M5 -TL -US
M6 -TL -US
M8 -TL -US
M10 -TL -US
Please note that there is an exception to the requirement of a dedicated circuit breaker in the buil-
ding circuit panel for each inverter if there exists a dedicated PV system AC subpanel that is used
to combine multiple inverters. In this case, only one breaker at the main building service panel
should be installed for a multiple inverter installation utilizing a dedicated PV system AC subpanel.
4.4

Grounding electrode conductor (GET)

Per NEC 690.47, a Grounding Electrode Conductor must be installed, and the GET conductor
must be sized in accordance with NEC article 250.166. The GET conductor should be terminated
at the GET screw terminal inside the wiring box compartment.
4.5

Lightning and surge protection

Delta M series NA inverters are designed and certified to meet stringent UL 1741 / IEEE 1547
and ANSI/ IEEE 62.41/62.42 AC lighting and surge requirements; however, every PV installation is
unique, thus additional external UL/NEC AC and DC surge protection and solid grounding practice
is recommended
4.6

Multiple inverters

Multiple Delta M series inverters are permitted at a common location if all applicable NEC, state,
local building codes and local utility commissioning guidelines are met. In addition, each inverter
should have its own dedicated AC branch protection circuit breaker and a dedicated PV string/
array, not to exceed the inverter's ratings.
26
Recommended AC branch protection
2-pole, 20 A 240 Vac
2-pole, 25 A 240 Vac
2-pole, 30 A 240 Vac
2-pole, 40 A 240 Vac
2-pole, 50 A 240 Vac