Load schedule sa lahat ng board
Maximum demand ng mga board ng site ayon sa switchboard diversity.
Reads AS/NZS 3000:2018. Tables checked 26 Sept 2026.
Subukan ang isang job 4
Nilalagyan ng halimbawang value ang bawat job. Palitan ang mga ito ng sarili mong value.
- Schedule a workshop site with four boardsThe demand of a main board, two boards and a mezzanine board by Table C4.
- Demand of a house with a garage boardThe single‑phase demand of a house board feeding a garage board.
- Check a submain device against its boardWhether a 160 A submain device covers a busy board of 14 circuits.
- Site demand for a supply applicationThe site demand in kVA of a shop with a main board and two boards.
Mga input
Worked example gamit ang mga default na input.
- Mga phase
- Three phase
- Voltage
- 400 V
- Mga board, unahin ang main board
- 3 row
- Sumusunod ang mga board sa AS/NZS 61439 o AS/NZS 3439
- Oo
Demand kada phase
325.5A
- Pinakamataas na demand ng site
- 225.5kVA
- Kabuuan ng mga rating sa main board
- 465A
- Mga board
- 3
Design aid lang ang resultang ito. I-verify ito laban sa kasalukuyang standard.
Mga hakbang ng kalkulasyon
- MSB: 8 device, kabuuan ng rating 465 A×0.70
AS/NZS 3000:2018 Table C4
- MSB: demand325.5A
AS/NZS 3000:2018 App C Para C2.4.4
- DB1: 12 device, kabuuan ng rating 260 A×0.60
AS/NZS 3000:2018 Table C4
- DB1: demand156A
AS/NZS 3000:2018 App C Para C2.4.4
- DB2: 8 device, kabuuan ng rating 150 A×0.70
AS/NZS 3000:2018 Table C4
- DB2: demand105A
AS/NZS 3000:2018 App C Para C2.4.4
- Demand kada phaseResulta325.5A
AS/NZS 3000:2018 App C Para C2.4.4
- Pinakamataas na demand ng site225.5kVA
Tungkol sa calculator na ito
How this is calculated
A load schedule lists the boards of a site and what each one draws. The tool works the maximum demand of each board by the switchboard diversity method of AS/NZS 3000 Appendix C, and carries it up the tree to the main board.
Para C2.4.4 sets the method for switchboards that conform to the AS/NZS 3439 or AS/NZS 61439 series. The maximum demand of a board is the sum of the overload ratings of its circuits, times a factor from Table C4. The factor falls as the number of circuit protective devices downstream rises.
On each board the tool counts its final subcircuit devices and one device for each submain it feeds. It adds the ratings of the final subcircuits and the rating of each submain device. The submain is a circuit of the board that feeds it, so a sub‑board's demand is never added twice. Table C4 prints no factor below two devices, and the tool then takes the sum as the demand.
The ratings are per phase. On a three‑phase board, enter the sum on the most loaded phase, and count a three‑pole device once. The tool gives each board's demand in amps and in kVA, and the site's demand at the main board.
Each sub‑board's demand is checked against the device that feeds it. A board whose demand is more than its submain device gets a warning.
The schedule prints as a sheet with one row a board.
| Step | Table or clause | What it decides |
|---|---|---|
| Devices on a board | Final subcircuits plus one a submain | The count Table C4 is read at |
| Sum of ratings | Para C2.4.4 | The circuits' ratings plus each submain device's rating |
| Diversity factor | Table C4 | The factor for the number of devices |
| Board demand | Para C2.4.4 | The sum times the factor |
| Submain check | The demand against the feeding device | Whether a submain device is smaller than its board's demand |
Worked examples
- A workshop site with four boards has a site maximum demand of 283.5 A a phase, 196.4 kVA. The main board's ratings add to 405 A.
- A house with a garage board has a maximum demand of 149.1 A, 34.3 kVA. The main board's ratings add to 213 A.
- A main board feeding one busy board has a site maximum demand of 200 A a phase, 138.6 kVA. The main board's ratings add to 250 A. The busy board's demand of 192 A is more than its 160 A submain device.
- A main board and two distribution boards has a site maximum demand of 325.5 A a phase, 225.5 kVA. The main board's ratings add to 465 A.
Limits
The method is only for boards that conform to the AS/NZS 3439 or AS/NZS 61439 series. For other boards, use another Appendix C method, such as the maximum demand tool. With the toggle off, the tool takes no Table C4 factor and gives the sum of the ratings.
It works from device ratings, not from the loads. A board full of large devices with small loads gives a high demand. A load-by-load assessment can give a lower figure.
See also: Maximum demand, Circuit loading and Max demand by phase.
Mga tanong
Design aid ang resulta. I-verify ito laban sa kasalukuyang standard.
Paano kinakalkula ang maximum demand ng switchboard?
Ayon sa AS/NZS 3000 Para C2.4.4, idagdag ang overload ratings ng mga circuit ng board at paramihin sa Table C4 factor para sa bilang ng device: 0.9 para sa 2 o 3, 0.8 para sa 4 o 5, 0.7 para sa 6 hanggang 9 at 0.6 para sa 10 o higit pa.
Paano binibilang ang sub‑board?
Ang submain ay circuit ng board na nagpapakain dito. Binibilang ito ng tool bilang isang device sa board na iyon, sa device rating nito. Kaya hindi na idinadagdag muli sa parent nito ang demand ng sub‑board.
Sa aling switchboard ina-apply ang method?
Ang Para C2.4.4 ay para sa mga switchboard na sumusunod sa AS/NZS 3439 o AS/NZS 61439 series. Para sa ibang board, gumamit ng ibang Appendix C method, gaya ng load groups ng Table C1 o C2.
Paano kung mas mataas ang demand ng board kaysa sa submain device nito?
Nagbababala ang tool. Mas maliit kung gayon ang device na nagpapakain sa board kaysa sa demand na ibinibigay ng method. Suriin ang device, ang cable at ang mga load sa board.
Paano ako mag-e-enter ng three‑phase board?
I-enter ang kabuuan ng mga rating sa pinakamabigat na phase, at bilangin nang isang beses ang three‑pole device. Ibinibigay ng tool ang demand kada phase at sa kVA sa voltage na itinakda mo.
Mga clause at table na binabasa ng tool na ito
- AS/NZS 3000:2018 App C Para C2.4.4Maximum demand by switchboard diversity
- AS/NZS 3000:2018 Table C4Upstream circuit loading after diversity
Bawat clause at table, kasama kung paano ito na-verify
Huling na-check ang mga table noong 26 Sept 2026.
Mga kaugnay na tool
- Maximum demand calculatorEstimate maximum demand for domestic or non‑domestic loads.AS/NZS 3000 Table C1/C2
- Maximum demand per phase calculatorSpread the load over three phases and see the imbalance.AS/NZS 3000
- Surge protection checkIs a surge protective device required or recommended here?AS/NZS 3000
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