Power Distribution Guide for Home Mining With Antminer KA3

This is a detailed power distribution guide for home mining with Antminer KA3 with the necessary electrical knowledge.

Choosing a mining pool and considering factors like electricity costs, power distribution, heat management, noise management, and getting started with Antminer KA3 mining can be challenging. Electrical power distribution is the most hazardous and poorly understood of these factors.

We intend to arm anyone interested in mining with an Antminer KA3 with the electrical knowledge necessary to get going as soon and safely as possible.

Electrical Setup Recommendation

If you have the option, we advise mining on 240V circuits with receptacles rated at 20A or 30A. Don’t worry if you don’t have this and can’t install circuits. Some ASIC miners can operate on 120V, the standard voltage used in the majority of North American homes.

Our preferred setup is 240V/20A circuits. Double-pole circuit breakers (20A rated), 12 AWG wires, and duplex outlets with NEMA 6-20R receptacles are required for this configuration.

If the panel is short on space, go with 240V/30A circuits. L6-30R receptacles, 10 AWG wires, double-pole circuit breakers rated at 30A, and UL listed PDUs with L6-30P plugs are all necessary for this configuration.

Regardless of whether you follow our advice or not, the following quick start guide will assist you in making sure that each part of your electrical setup is operating within safe parameters. As we go, we’ll use examples to illustrate the points that need to be taken into account.

Power Distribution Guide for Home Mining

Step #1. Calculate the Max Current Demand for Each Miner.

When preparing to install new miners, think about current (amps). Because all circuit breakers, electrical wire, outlet receptacles, power distribution units, and power cords have amp ratings, capacity planning is made simpler.

To begin, look up the Antminer KA3’s maximum power consumption in Watts in the user manual. The worst-case current demand can then be calculated by converting Watts to Amps. The voltage supplied to the miner affects how to convert Watts to Amps.

Current (Amps) = Power (Watts) / Voltage (Volts)

In North America, 120V and 240V are the most widely used residential voltages. A miner using 1200W will use 10A on 120V and 5A on 240V. In order to power more miners on the same circuit, higher voltages must be used because they can deliver the same power with less current.

A few modern miners, like the Antminer KA3, need two power inputs. Both inputs share the same amount of current draw. For instance, if a dual input miner needs 14A of current overall, each input will only use about 7A of current.

Antminer KA3 with two power inputs

Examples

Antminer KA3 with dual power input and 166T hash rate.

Max Power (Watts) @ 95T = 3154 + 5% = 3154.5W

Current Demand @ 240V = 3154.5W / 240V = 13.14A, 6.5A per input

Step #2. Double Check the Circuit(s).

Double Check the Breaker(s).

It’s crucial to check that the current demand from your miners doesn’t overload any components on the circuits where they’ll be installed. We must use the 80% rule to determine the circuit’s derated current capacity in order to verify this.

Circuit Derated Capacity = Circuit Current Rating * 80%

The National Electric Code (NEC) states that for continuous loads, a circuit may be loaded up to 80% of its current rating. As an example, your miners are considered a continuous load because their maximum current is anticipated to last for at least three hours.

The maximum ampere rating of the overcurrent protection device (OCPD), usually the circuit breaker, is used to rate circuits. As a result, a circuit’s derated capacity is equal to 80% of the circuit breaker’s current rating. Circuits with 20 amp breakers and 30 amp breakers each have a 16 amp capacity and a 24 amp capacity, respectively.

In North American residential homes with “Split-Phase” electrical service, single pole breakers are required to protect 120V circuits and double pole breakers are required to protect 240V circuits. A single pole breaker occupies one slot, while a double pole breaker occupies two slots in a panel.

Check the handle for a marking to determine the current rating of a circuit breaker. The number “20” will be prominently printed on the breaker handle, for instance, if it is a 20A rated breaker.

Single Pole (Left) and Double Pole (Right) Circuit Breaker

Check #1:

Current Demand < 80% Circuit Breaker Current Rating

Make sure the total current demand from all miners on the same circuit do not exceed 80% of the circuit breaker rating.

Double Check the Wires.

The electrical wires must be larger to prevent excessive heat that could melt the wire insulation and start a fire, which happens when the circuit’s amperage rating is higher.

Wire is sized by the American Wire Gauge (AWG) system. The diameter of the wire increases with decreasing gauge number. For standard non-metallic (NM) wire, reference the following table:

Verify again the size of the wires on your circuits. You should have been given consideration if the circuit was installed by a certified electrician, but don’t take our word for it—verify first. The wire insulation bears a printout of the wire size.

Check #2:

Wire Current Rating ≥ Circuit Breaker Current Rating

Make sure the wires’ current rating is greater than or equal to the circuit breaker’s current rating.

Double Check the Receptacle(s).

Electrical code mandates that the receptacle’s current rating cannot be less than that of the circuit breaker on circuits with only one outlet. The explanation is straightforward: for devices designed to plug into 20A outlets, the upstream breakers must trip at 20A, not 30A.

Check #3:

Receptacle Current Rating ≥ Circuit Breaker Current Rating

Check to make sure the circuit breaker’s current rating is greater than the receptacle’s current rating.

Circuits with two or more outlets are exempt from this rule. These circuits must comply with NEC Table 210.21(B)(3):

With one exception, 15A outlet receptacles can be used on circuits with 20A breakers. Each outlet in these configurations will only have a derated capacity of 12A, whereas the circuit as a whole will have a larger derated capacity of 16A.

Check #4:

Current Demand < 80% Receptacle Current Rating

Make sure the total current demand from miners on the same receptacle do not exceed 80% of the receptacle’s current rating.

Table of reference for typical types of outlets and their current ratings.

NEMA

Voltage

Current

Derating

5-15R

120 VAC

15A

12A

5-20R

120 VAC

20A

16A

6-20R

240 VAC

20A

16A

L6-20R

240 VAC

20A

16A

L6-30R

240 VAC

30A

24A

10-30R

240 VAC

30A

24A

14-30R

120/240 VAC

30A

24A

14-50R

120/240 VAC

50A

40A

Receptacles with the NEMA 10-30R designation are unsafe and out of date. The trash cans are typically found in houses that were constructed before 2000.

Is mining allowed to use a dryer outlet?

The use of a PDU with integrated branch circuit breakers that is UL listed is advised if you still decide to do this even though it is not advised. Branch breakers must comply with UL-489 listing requirements.

The example below assumes that miners will be linked to a dedicated circuit, which is strongly advised. no other home appliances or loads will be connected. It is advised to first measure or estimate the current demand for all connected devices if you intend to use a shared circuit to avoid overloading the circuits.

Question: How many Antminer KA3s can be safely powered on a 20A/240V circuit with NEMA 6-20R outlets and a 166T hash rate?

Answer: One.

Calculated current demand for the Antminer KA3 is 13.14A @ 240V.

Total current demand of a single KA3 at 13.14A is below the 16A derated capacity of the circuit and receptacle.

Step #3. Plug in the Miner(s).

The miners are attached to the outlets as the final step.

The two most typical input connector types found on ASIC miners are listed in the following table along with the corresponding mating connectors.

Connector (IEC)	Miner Input (IEC)	Current Rating	Diagram
C13	C14	15A (12A Derated)
C19	C20	20A (16A Derated)

ASIC miner power supplies are designed with International Electrotechnical Commission (IEC) connectors for international compatibility while the circuit receptacles are National Electrical Manufacturers Association (For use primarily in North America, NEMA) connectors.

A power distribution unit (PDU) or a straightforward power cord can be used to connect IEC to NEMA. PDUs are required for safe operation of 30A circuits. PDUs are not essential for 20A circuits.

Using Power Cord(s) Only

The simplest method involves using a power cord that is the right size, has an IEC connector on one end and a NEMA plug on the other.

NEMA 6-15P to IEC C13 Power Cord

The recommended power cords for attaching miners directly to circuits rated 20A or less are listed in the table. You can find the power cords you need by matching the outer columns to your setup.

Using a PDU

There are two main factors for setup compatibility, which will simplify PDU selection.

1. PDU Input Plug Type
2. PDU Receptacle Types

1. To connect to the NEMA outlet receptacle installed on the circuit, pick a PDU with a matching NEMA plug. To find the matching plug, simply replace the ‘R‘ with a ‘P‘ in the NEMA type. For example, the matching plug for a NEMA 6-20R receptacle is a NEMA 6-20P.

2. A C19 outlet should be present in the PDU if your miner has a C20 input. The PDU ought to have C13 plugs if your miner has a C14 input. Once that is done, standard C14 to C13 or C20 to C19 power cords can be used to connect the PDU to the miners.

What is Voltage, Current, and Power?  

This overly simplistic watermill analogy has many technical issues but is a good starting point for a basic understanding.

Voltage is the water pressure on the wheel.

Current is the amount of water flowing onto the wheel. 

Power is the rotational speed of the wheel.

The relationship between these is as follows.

Power (Watts) = Current (Amps) * Voltage (Volts) 

If we wanted to use this water wheel to power an ASIC miner, the wheels needs to spin at a constant rotational speed to keep the miner turned on. To achieve a certain speed we have two options.

Method #1: Increase the water pressure (voltage) on the wheel. This can be done by elevating the water spout, leveraging gravity.

Method #2: Increase the amount of water (current) flowing on to the wheel.

Both methods achieve the same effect of increasing the rotational speed (power) of the wheel. In electrical terms, it is better to run higher voltages to reduce current. Lower current allows for smaller wires, more capacity for more miners with existing infrastructure, and increased power supply efficiency.

What’s the difference between 110V, 115V, 120V, 220V, 230V, 240V?

You will often see these values being used to describe voltages in your home. We can categorize these into two groups…

• Group #1: 110V, 115V, 120V
• Group #2: 220V, 230V, 240V

The voltages in the same groups can be and are often used interchangeably. North American residential homes typically have “split-phase” electrical service from the transformer on the street. For split-phase service, the voltage measured from any “hot” wire to neutral (ground) is ~120V. The voltage measured from one hot wire to another hot wire on a different phase is ~240V.

The voltages are not constant and varies depending on a number of factors such as the number of loads connected, the time of day, etc. For example, if you were to measure the voltage at the input of an ASIC miner connected to a 240V outlet, there’s a small chance you will see exactly 240V. This is not a problem because the ASIC miner power supplies are designed to support a wide range of voltages.