STRCOM Fused String Combiners
Installation and Operation Manual
DOC-020040 rev 4.4
11
A
12 or 15A
fuse can be selected for this module.
Example 3: PV module with 8.12A short circuit current rating and a 15A fuse rating.
1.56 x 8.12A= 12.667A
A
15A
fuse must be selected for this module.
Connection of Grounded Conductor Terminal Block (negative conductors):
The grounded connection terminal block in the standard version combiner, for array
and inverter connections is grounded by the inverter and is not to be grounded
anywhere else. In the standard version of the combiner, for negatively grounded
systems, the PV array negative and inverter negative conductors connect to this
block. (This block is used for the positive array and inverter connections in an
optional version for positively grounded systems.)
ARRAY CONNECTIONS: conductor size 8-12AWG can be used to connect to each
solar array string terminal block. Torque to 35 in-lb
INVERTER CONNECTIONS: conductor size 4AWG-400KCM can be used to
connect from the terminal block to the inverter. Torque to 375 in-lb
Connection of Ungrounded Conductors for fuses (positive conductors):
The ungrounded array conductors (positive conductors in a standard negatively
grounded system) connect to the fuses. One PV string connects to each fuse position.
ARRAY CONNECTIONS: conductor size 8-12AWG can be used to connect to each
solar array string fuse holder. Torque to 18-22 in-lb
INVERTER CONNECTIONS: conductor size 6AWG-350KCM can be used to
connect from the terminal block to the inverter depending on string combiner version:
# of wire
String Combiner Version
positions
Wire size
Torque
4-12 fuse
1
6AWG-250KCM
275 in-lb
13-24 fuse
1
4/0 – 350KCM
340 in-lb
(or
2
1/0 – 250KCM
340 in-lb)
25-30 fuse
1
6AWG-250KCM
275 in-lb
and 1
4/0 – 350KCM
340 in-lb
(or
2
1/0 – 250KCM
340 in-lb)
Conduit Entrance locations:
It is recommended that PV array string conductor conduit(s) enter the lower right
corner of the combiner enclosure on the bottom or right wall. Array conduit(s) can
also enter anywhere on the right side or top right corner of the enclosure but to
maintain the NEMA4 rating of the combiner, NEMA4 rated, liquid-tight conduit
connectors must be used.
It is recommended that the conduit(s) to the inverter(s) exit the center of the enclosure
bottom.
Grounding Conductors:
The array frame and mounting structure equipment ground conductors should be
terminated on the ground bar provided in the combiner. There are several connection
