PV isolator and earthing calculator
I-rate ang PV array cable, d.c. isolator at earthing.
Reads AS/NZS 3000:2018 and AS/NZS 5033:2021. Tables checked 1 Oct 2026.
Subukan ang isang job 4
Nilalagyan ng halimbawang value ang bawat job. Palitan ang mga ito ng sarili mong value.
- Rate the d.c. isolator for a solar arrayCheck an isolator data sheet against two strings at 520 V in the sun.
- Size the earth for a PV array frameThe frame earth for a powered-neutral inverter on 6 mm² array cable.
- Find the currents in a commercial arrayString, sub-array and array currents for 12 strings in three fused sub-arrays.
- Set the earth fault interrupterThe detection setting for a 60 kW array with direct functional earthing.
Mga input
Worked example gamit ang mga default na input.
- Module Isc
- 13.9 A
- KI, bifacial factor
- 1
- Mga string na nakaparalelo
- 4
- Mga string kada sub-array
- 0
- Pinakamataas na voltage ng array
- 450 V
- Array power
- 0 kW
- Backfeed current mula sa inverter
- 0 A
- Rating ng string fuse
- 0 A
- Rating ng proteksyon ng array
- 0 A
- Inverter
- Non‑separated (walang transformer)
- Functional earthing ng array
- Wala
- Isolator sa
- Ang array cable
- Lokasyon ng isolator
- Sa labas, nasa araw
- Voltage rating ng isolator
- 0 V
- Isolator Ithe sa ambient
- 0 A
- Isolator Ie, mga pole na nakaserye
- 0 A
- Make and break current ng isolator
- 0 A
- Disconnection device
- Switch-disconnector
- Enclosure
- Nakalaan, isang switch
- Enclosure sa labas
- Oo
- Nakakonekta sa sistemang may earth reference
- Oo
- Frame na nakaground para sa proteksyon sa kidlat
- Hindi
- Laki ng array cable
- Hindi nailagay
- Laki ng inverter a.c. cable
- 6 mm²
d.c. isolator Ithe sa 60 °C, pinakamababa
69.5 A sa 450 V
- String cable current
- 52.13A
- Array cable current
- 69.5A
- Isolator Ie, mga pole na naka-series, hindi bababa sa
- 69.5A
- Earth conductor, hindi bababa sa
- 4mm²
Design aid lang ang resultang ito. I-verify ito laban sa kasalukuyang standard.
Mga hakbang ng kalkulasyon
- Pinakamataas na string current, 1.25 × KI × Isc17.38A
AS/NZS 5033:2021 Cl 3.3.3.1
- Fault current mula sa ibang string, (SA − 1) × ISTRING MAX52.13A
AS/NZS 5033:2021 Cl 3.3.3.2
- Current ng string cable52.13A
AS/NZS 5033:2021 Table 4.2
- Array cable current69.5A
AS/NZS 5033:2021 Table 4.2
- Voltage rating ng isolator, hindi bababa sa maximum voltage450V
AS/NZS 5033:2021 Cl 4.3.4.1
- Isolator Ithe sa operating ambient, hindi bababa sa69.5A
AS/NZS 5033:2021 Cl 4.3.4.2.3
- Ang operating ambient Ithe ay de-rated para sa60°C
AS/NZS 5033:2021 Cl 4.3.4.2.3(a)(iii)
- Isolator Ie, mga pole na nakaserye, hindi bababa sa69.5A
AS/NZS 5033:2021 Table 4.3
- I(make) at Ic(break) ng bawat pole, hindi bababa sa69.5A
AS/NZS 5033:2021 Table 4.3
- Earth mula sa table2.5mm²
AS/NZS 3000:2018 Table 5.1
- Earth o bonding conductor, tanso, hindi bababa sa4mm²
AS/NZS 5033:2021 Table 4.6
Tungkol sa calculator na ito
How this is calculated
The tool completes the PV string tool. It takes the module Isc, the strings and the array maximum voltage. It gives the cable currents, the d.c. isolator ratings, the enclosure and the earthing. It reads AS/NZS 5033:2021.
- String current. It works 1.25 × KI × Isc (Cl 3.3.3.1). Each string can also take fault current from the other strings (Cl 3.3.3.2).
- Cable currents. It gives the string, sub-array and array cable currents (Table 4.2).
- Protection. If you enter a sub-array or array protective device, it checks the rating against the strings it covers (Table 3.1).
- Isolator voltage and current. The voltage rating is at least the array maximum voltage (Cl 4.3.4.1). Ithe is read at 40 °C indoors or in the shade, and at 60 °C outdoors in the sun (Cl 4.3.4.2.3).
- Make and break. A non‑separated inverter, or a functionally earthed array, needs each pole to break the full current (Table 4.3). A separated inverter lets the poles in series share it (Table 4.4).
- Enclosure. It gives the enclosure rule (Table 4.5). Outdoors, it adds the pressure-equalisation valve (Cl 4.4.6.2).
- Earthing. Above 35 V it reads Figure 4.13 and the Table 4.6 columns. It takes the earth size from AS/NZS 3000 Table 5.1, and never less than 4 mm². It adds the 0.5 Ω limit (Cl 4.6.5).
- Earth faults. A direct functionally earthed array gets an interrupter setting (Table 3.2). The tool adds an earth fault alarm above 120 V, or for a non‑separated inverter (Cl 3.5.3).
| Step | Table or clause | What it decides |
|---|---|---|
| String current | Cl 3.3.3.1 and Cl 3.3.3.2 | The current of one string and its fault share |
| Cable currents | Table 4.2 | The current in the string, sub-array and array cable |
| Protection | Table 3.1 | The least rating of sub-array and array protection |
| Isolator rating | Cl 4.3.4.1 and Cl 4.3.4.2.3 | The voltage and the Ithe |
| Make and break | Table 4.3 and Table 4.4 | The current each pole, or the poles in series, must break |
| Enclosure | Table 4.5 and Cl 4.4.6.2 | The enclosure type and the valve |
| Earth conductor | Figure 4.13 and Table 4.6 | The frame earth or bonding conductor |
| Earth faults | Table 3.2 and Cl 3.5.3 | The interrupter setting and the alarm |
Worked example
- 4 unfused strings of 13.9 A modules, 450 V, non‑separated inverter. The string current is 17.38 A. The string cable carries 52.13 A and the array cable carries 69.5 A. The isolator sits at the array in the sun, so Ithe is read at 60 °C and must be at least 69.5 A at 450 V. Ie must be at least 69.5 A. Each pole must break 69.5 A. The earth is 4 mm².
Limits
- The tool does not size cables. It gives each current. Use the DC cable size calculator for the conductor.
- The 1.25 factor and the 4 mm² least conductor come from the PV string limits. The tool derives them from the text of AS/NZS 5033 until the Standard is checked.
- The maker's data sheet governs the isolator. Enter its Ithe, Ie and make and break figures to run the checks.
- The array maximum voltage comes from the PV string tool. Run that tool first.
See also: DC isolator rating for a 10 kW solar array, PV array isolators and earthing, PV string calculator and DC cable size calculator.
Mga tanong
Design aid ang resulta. I-verify ito laban sa kasalukuyang standard.
Anong current ang dinadala ng PV array cable?
Itinatakda ito ng AS/NZS 5033 Table 4.2. Ang string na walang fuse ay dala ang fault current na kayang ipasok ng ibang string, kasama ang pinakamalapit na protection sa downstream o ang backfeed. Dinadala ng array cable ang bawat string sa 1.25 beses ng Isc.
Paano ko ire-rate ang d.c. isolator para sa solar array?
Tingnan ang apat na figure sa maximum voltage ng array: ang voltage rating, Ithe sa 40 °C o 60 °C sa araw, Ie na may poles sa series, at ang make at break current. Ang transformerless inverter ay nangangailangan na kayang putulin ng bawat pole ang buong current.
Anong laki ng earth ang kailangan ng PV array frame?
Sundin ang Figure 4.13 ng AS/NZS 5033. Ang lightning protection ay gumagamit ng 16 mm². Kung hindi, ang uri ng inverter at ang d.c. protection ang pumipili ng column sa Table 4.6. Ang pinakamaliit na size para sa frames ay 4 mm².
Ina-i-size ba ng tool ang mga d.c. cable?
Hindi. Ibinibigay nito ang current na dapat dalhin ng bawat cable. I-size ang bawat cable gamit ang d.c. cable size tool sa current na iyon, hindi bababa sa 4 mm², sa mainit na cable temperature malapit sa mga module.
Kailan kailangan ang earth fault alarm?
Ang AS/NZS 5033 Cl 3.5.3 ay nangangailangan nito kapag higit sa 120 V, o kapag may inverter na hindi hiwalay. Ang directly earthed array ay nangangailangan din ng earth fault interrupter na itinakda ng Table 3.2 batay sa array power.
Mga worked example
Background
Mga clause at table na binabasa ng tool na ito
- AS/NZS 5033:2021 Cl 3.3.3.2Fault current from parallel strings
- AS/NZS 5033:2021 Cl 3.5.3Earth fault alarm
- AS/NZS 5033:2021 Cl 4.3.4.1PV isolator voltage rating
- AS/NZS 5033:2021 Cl 4.3.4.2.3Ratings of a PV d.c. switch-disconnector
- AS/NZS 5033:2021 Cl 4.4.2.2PV cable temperature
- AS/NZS 5033:2021 Cl 4.4.6.2Outdoor enclosure pressure equalization
- AS/NZS 5033:2021 Cl 4.6.5Frame earth resistance
- AS/NZS 5033:2021 Figure 4.13Frame earthing conductor
Bawat clause at table, kasama kung paano ito na-verify
Huling na-check ang mga table noong 1 Oct 2026.
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