Selecting Suitable Fuses Where Needed - EcoInnovation React Pump System Design And Installation Manual

PowerSpout

I =< 15A
n
Hence a fuse =< 15 amp and > 13.91 A is required per string when 3 or more strings of
Yingli 270W are connected to an React pump.
Summary (fuses required per string)
Panel example
260W Renesola
270W Yingli
Note that 15 amp MC4 inline fuses are widely available and low cost
Hence is this example, for the correct application of AS/NZS 5033, some panel makes
require string fuses while other makes may not. If you are careful in selecting the make of
panel for your React pump application then you can avoid the need for string fuses.
Do both poles need protection? (normally only the positive pole is fused)
AS/NZS 5033 states in section 3.3.6 that:
In ELV arrays, overcurrent protective devices, where required for string and sub-
array cables, shall be placed in either the positive or negative conductor (the number
of current carrying conductors minus one). Where the extra-low voltage array is
earthed, the protective devices shall be installed in all unearthed current carrying
conductors.
Section 4.4.2.1 states:
In PV arrays with a PV array maximum voltage greater than ELV and in systems
which include a.c. modules and microinverters with LV outputs, all exposed metal PV
module frames shall be earthed and the array mounting frames shall also be earthed.
Earthing/bonding of exposed conductive parts of a PV array shall be performed in
accordance with Figure 4.5 decision tree.
Hence there is no requirement to earth an ELV PV array, only an LV one.
3.2.4.

Selecting suitable fuses where needed

Here is what the regulations tell us
The maximum voltage is found as follows (next page.)
© 2019 EcoInnovation Ltd (NZ) V2.1
1-string 2-string
N/A N/A
N/A N/A
React Pump Installation
3-string 4-string
(not
advised)
N/A 14- 20 amp
14-15 14-15 amp
amp
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