INSTALLATION GUIDE
MODULAR SUNWAY TG
TE OD
Rev. 03
– 01/06/2018
93/
139
𝑻
𝑰𝑵𝑻
= 𝑻
𝑨𝑴𝑩
+ 𝟏𝟎°𝑪
EXAMPLE:
Consider T
INT MAX
= 60 °C. A1= 0.836. A 200 A rated fuse is compatible with input current ratings up to 167
A.
In PV plants, current is a function of solar radiation. The values in Table 27 are given as an indication for
the fuse trip time based on the current flowing and the fuse size.
Fuse size
In [A]
Current
2 x In [A]
Trip time
[s]
Current
3 x In [A]
Trip time
[s]
Current
4 x In [A]
Trip time
[s]
50
100
150
150
10
200
2
63
126
150
189
20
252
2
80
160
100
240
10
320
1
100
200
200
300
30
400
7
125
250
200
375
25
500
7
160
320
300
480
40
640
15
200 A
400
400
600
60
800
18
Table 27: Trip time of NH1-XL fuses
9.2.
DC input cable dimensioning
The connection cables between the String Boxes, which are typically located in proximity to PV modules,
and the inverters, located in the technical room, normally carry the current delivered from the string units
connected to one single String Box.
Since the PV field is a limited current generator, even in case of short-circuit, the current delivered by that
generator cannot exceed the maximum dimensioning value. This does not apply to the current carried by
the cables.
Consider short-circuit occurring downstream from a String Box but upstream from the inverter cabinet (see
Figure 63). In that case, the current carried by all the String Boxes but one is delivered to the cable portion
ranging from the point where short-circuit occurs to the point of connection to the inverter.
