This field project involved upgrading an existing agricultural electrical system to supply two 3.5kW electric chili pepper dryers at a farm in Icheon, South Korea.
The dryers had not yet arrived at the site. Before the work began, I spoke with the dryer supplier by phone and was told that each unit had a power consumption of approximately 3.5kW at single-phase 220V.
The installation itself was not especially complicated. The more interesting part was deciding how much of the existing electrical system could reasonably be used, selecting the branch protection, and later discovering that the actual dryer layout was different from the drawing provided before construction.
Location: Icheon, South Korea
Supply: Single-phase 220V
Existing contracted power: 5kW
New equipment: Two 3.5kW chili pepper dryers + small ventilation fan
Existing main breaker: 2P 30A ELCB
Upgraded main breaker: 2P 40A MCCB
Dryer branch protection: 2P 20A ELCB per dryer circuit
Dryer feeder: CV 3C 2.5mm² × 2 circuits
Actual cable run: Approximately 35m per circuit
Overall view of the chili pepper farm before electrical work began.
Existing Agricultural Electrical System
Before modifying the panel, I inspected the existing agricultural electrical supply.
The service cable coming down from the utility pole was CV 2C 6mm². From the utility meter to the line side of the main breaker, 6mm² HIV conductors were installed.
The installed utility meter was rated 50(10)A.
The existing panel included:
- 2P 30A Earth Leakage Circuit Breaker as the main breaker
- One 2P 20A branch Earth Leakage Circuit Breaker
- A power factor correction capacitor
- An existing receptacle circuit
The site's existing contracted power was 5kW.
Existing agricultural distribution panel before modification.
Why I Chose 20A Branch Breakers
One of the main decisions on this job concerned the breaker sizes for the two dryers.
The dryer supplier told me by phone that they wanted a 30A Earth Leakage Circuit Breaker for each dryer.
However, the machines were not yet at the farm, so I could not inspect their nameplates or verify the manufacturer's rated current directly. The information available to me was that each dryer consumed approximately 3.5kW at 220V.
Using the information available at the time:
From the information I had about the equipment, the dryer was primarily an electric heating appliance with only a relatively small fan motor. I therefore did not expect the type of large starting current associated with a substantial motor load.
Based on the expected operating characteristics and the information available at the time, I selected a 2P 20A ELCB for each dryer branch circuit.
This was a field judgment for this particular installation. It should not be interpreted as a general rule that every 3.5kW dryer should use a 20A breaker.
Upgrading the Main Distribution Panel
The original main breaker was a 2P 30A ELCB.
With two dryers rated at 3.5kW each, the connected dryer load alone was approximately 7kW, with only a relatively small amount of additional load expected at the site.
I replaced the existing 30A main breaker with a 2P 40A MCCB.
At single-phase 220V, 40A corresponds to a theoretical apparent-power limit of:
The existing service conductors, the 50(10)A utility meter, expected load pattern, and the site's 5kW contracted power were all considered when reviewing the existing supply.
A substantially larger electrical service would have required a broader review of both the installation and the utility supply conditions.
To make room for the additional branch breakers, I also removed the existing power factor correction capacitor from the enclosure.
The upgraded panel included:
- 2P 40A MCCB as the main breaker
- Additional 2P 20A Earth Leakage Circuit Breakers
- 30mA leakage sensitivity on the installed branch ELCBs
Agricultural distribution panel after upgrading the main breaker to 40A and adding dedicated 20A branch circuits.
Installing Two Feeder Circuits
Before I arrived at the farm, the customer had measured the route and told me that approximately 40m of cable would be required for each dryer circuit.
Based on that information, I prepared two runs of CV 3C 2.5mm² cable.
After completing the actual installation, approximately 5–6m remained from each 40m length. The real cable route was therefore closer to 35m per circuit.
Each three-core cable was used for line, neutral, and protective earth, with one conductor serving as the protective earth conductor.
The basic installation sequence was:
- Confirm the planned cable route
- Install CD conduit where required
- Insert fish tape through the conduit
- Pull the CV 3C 2.5mm² cables
- Terminate the circuits at the new enclosure
Installing the feeder route across the farm and pulling the CV cables through the conduit using fish tape.
The Equipment Layout Was Different From the Drawing
This became the most useful lesson from the project.
Before construction, the customer provided a drawing showing the two dryers installed in separate locations. The customer also told me by phone that he had measured the cable route and that two 40m runs would be sufficient.
Based on that information, I prepared and began installing two independent feeder circuits.
After the wiring work had already begun, I learned that the two dryers would actually be installed side by side.
If I had known the final equipment layout from the beginning, I would have considered:
↓
One 6mm² Feeder
↓
Local Distribution Panel Near the Dryers
↓
40A Main Breaker
↓
Separate 20A Branch Circuits
Existing, As-Built, and Alternative Design
The diagram below compares three different configurations.
- Existing System: The agricultural electrical system before the upgrade.
- As Built: The configuration actually installed during this project.
- Alternative Design: The arrangement I would have considered if the final dryer locations had been known before the wiring began.
The alternative design shown here was not the system installed at this site. It is included to explain how accurate equipment-location information can change feeder and distribution planning.
Comparison of the existing electrical system, the actual installation, and an alternative local distribution design.
Weatherproof Distribution Box at the Dryer Location
At the dryer location, I installed a 300 × 200 weatherproof enclosure for the final circuit connections.
The two dryer feeder circuits were brought into this enclosure. A small window-type ventilation fan was also supplied from one of the dryer circuits.
The ventilation fan was a very small load compared with the dryer. Because I did not record its exact nameplate rating, I am not assigning a specific wattage to it here.
Temporary Cable Routing for Seasonal Use
There was another site-specific condition that affected the work.
The farm layout would change after the chili pepper growing season, and the customer planned to remove the cables after harvest.
For a permanent outdoor installation, I would normally prefer a properly protected permanent cable-routing method rather than leaving feeder cables exposed at ground level.
In this case, however, the customer specifically requested a temporary seasonal arrangement that could later be removed.
Temporary feeder cable routing across the field for seasonal use.
Working Against the Weather
The work was carried out in midsummer. The temperature was above 30°C (86°F), humidity was high, and heavy rain was forecast for later in the afternoon.
We started at approximately 9:30 AM and completed the work at around 3:00 PM.
The site was approximately 80km from my home, requiring roughly 2.5 hours of driving each way. With rain approaching, efficient preparation was particularly important that day.
Completed electrical installation at the dryer location before the two dryers were delivered.
Tools and Materials Used
The main tools and materials used during the installation included:
- Battery-powered hydraulic crimping tool
- Fish tape
- Cable cutter and wire stripper
- Multimeter
- 2P 40A MCCB
- 2P 20A Earth Leakage Circuit Breakers
- CV 3C 2.5mm² cable
- CD conduit
- Cable lugs and connectors
- 300 × 200 weatherproof enclosure
The battery-powered hydraulic crimper was particularly useful because it allowed cable terminations to be completed quickly and consistently while we were working against the approaching rain.
Electrical tools, CV cables and connection materials prepared on site before installation.
Final Result and Field Lesson
By the end of the work, the electrical infrastructure was ready for the two 3.5kW dryers, although the machines themselves had not yet arrived at the farm.
Looking back, the most valuable part of this project was not the physical installation itself.
The two independent feeder circuits were installed according to the equipment-location information available when the job began. Once I learned that the dryers would actually be placed side by side, it became clear that a different distribution arrangement could have been cleaner.
If I were planning the same installation again with the final layout known in advance, I would consider bringing one larger feeder to a local distribution panel beside the dryers and branching the individual circuits there.
On a small electrical project, equipment location can affect the wiring design almost as much as equipment capacity. Confirming the final equipment position before preparing long feeder runs can reduce unnecessary cable and produce a cleaner distribution layout.
Electric Korea
Korean Electrical Construction · Field Experience · Safety · Technical Education
Website: electrickorea.co.kr
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