STANDARD OPERATING PROCEDURE
String Inverter Installation – Zeverlution Series
Version 1.2 Effective date 02/08/2017
Page 7 of 15
Any DC cabling must be adequately mechanically protected and must be run in HD Solar conduit.
Where it is exposed to direct sunlight, HD conduit, marked with the letter T, is to be used. For any
internal cable runs (e.g. within wall cavities, under floors and within roof spaces), rigid HD solar
conduit shall be used. The conduit must be labelled with PV or SOLAR at intervals not exceeding
2 meters. Refer to section 4.3 of AS/NZS 4777.1:2016. Use stainless steel saddles for all external
conduit runs.
Wiring between the inverter and the DC isolator may be without conduit where the length of DC
cable does not exceed 300mm.
The minimum cross section of any DC wiring is 4mm². All DC cables shall be multi-stranded,
insulated and sheathed and PV1-F rated as per AS5033. The table below shows the maximum
cable length (one way) between array and inverter with JA 290W panels, allowing for a 2% voltage
drop.
Panels per string
3
4
5
6
7
8
9
10
Max. cable length
25
25
25
30
35
40
45
50
Genuine MC4 connectors must be used to connect the DC cables to the array output cable. A
MC4 crimping tool is required to attach the stranded wire to the metal pin.
DC isolators
DC isolators must be installed adjacent to the inverter. The clearances for the inverter provided in
section 5.2.4 do not apply for any disconnection equipment. This means isolators can be installed
directly underneath or next to the inverter.
Solarcity supplies a Kraus & Naimer DC isolator - KFD25 T204/NZ-P002 KL11V. It is important that
the screw terminals of the DC isolator are not over tightened. A torque screwdriver shall be used
to tighten the terminal screws with a torque of 1.25Nm.
Remove the isolator from the enclosure prior to fixing the enclosure to the wall. Dust from drilling
can damage the switch.
Please see the
