Cutter Designs

DIY Custom Power Supply

1x - XFR-1006E Transformer

1x - Fuse Holder and 1amp Fuse

1x - Male extension cord end

1x - 15a Single Pole Switch w/ Pilot Light

1x - Lutron D-600R Dimmer Switch

1x - Double Pole Double Throw Toggle Switch

2x - Panel Mount Binding Posts

10’ - 14ga stranded connection wire

5’ - 14-2 copper service/housing wire

~9x - Connection/Screw Caps

Those items that are underlined provide direct links to suppliers/retailers that sell the products online.

CLICK HERE_DIYPSDesign_files/2013,%200429%20-%20Custom%20Power%20Supply_2.pdf
PDF available for download_DIYPSDesign_files/2013,%200429%20-%20Custom%20Power%20Supply_3.pdf

Listed herein are the visual and printable schematics for your own

Do-It-Yourself Step Down Power Supply

The following section is in direct response to many visitors asking how to make their own power supply and/or wanting a more powerful power supply that costs less than those commercially available.

For years our recommendation has been to purchase a commercially available DC power supply for use on all hobby hot wire foam cutters. Not only this, but to specifically shy away from any AC power source and/or creating your own power supply using a doorbell transformer (which is a AC Step Down Transformer).

There were a few reasons behind this recommendation, but was seated primarily in safety of you or those around you. The fact of the matter is, most AC transformers commercially available are meant for use in high end settings and provide anywhere from 120-240 volts and up to 5000 watts. It would have been irresponsible to recommend the casual hobbyist to purchase and use on of these dangerous supplies.

Next, commercially available doorbell transformers are simply not rated for any application that requires more than 1.5 amps to heat their nichrome wire. As a result, many people would find that after prolonged use or excessive power supply demand, the door bell transformer would simply short out.

So rather than provide unreliable and unsafe options, we have always taken the stance to recommend commercially available DC power supplies which were safer to use.


1x - Triple Gang Electrical Box

10-12”  -  2x4 plank wood

Structural Components

Electrical Components


Jacobs Online (while being a wonderful source of NiChrome Wire) created custom AC Step Down Transformers with hot wire foam cutters in mind!

They worked directly with the manufacturer to create a power supply that had a wide range of temperatures for all gauges and lengths of NiChrome Wire.


The Jacobs’ transformers are exactly what you need if you have any interest in making your own power supply. So stop searching the internet for something better, because the fact of the matter is, there is nothing better we’ve been able to find. And yes, this is an unpaid endorsement. They’re really that good!


We’ve selected the XFR-1006E as the optimal step down transformer for all hobby sized hot wire foam cutters. Jacobs Online has other power supplies that may be a better fit for your project, but this one was selected because of the range of wires it can heat at a large range of lengths.

Before proceeding to the steps below, it is important that you understand how transformers function. Jacobs Online has written a wonderful article that discusses their function. You can find it following this link.

Jacobs Online has their own recommendations for power supply design from which we adapted our design. In fact, we tried to include as many components in our design in order to show how each are wired and function. For most applications our design is more than what is practically needed, but you may find it the right fit for your project. Follow this link to Jacobs Online power supply diagrams.

Remember, this is meant to be a guide only and we do not take responsibility for any loss or damage to you or personal goods. Proceed at your own risk.


By now you should have read through Jacobs Online’s transformer informational page as well as reviewed some of their designs. The XFR1006E power supply is able to provide two main electrical states.

Parallel Arrangement - Double Amperage - 6 volts / 16.7 amps

Series Arrangement - Double Voltage - 12 volts / 8.3 amps


When placed in parallel (6v/16.7a), the power supply is able to provide enough amperage to higher gauge nichrome wire (14g-20g) to achieve cutting temperatures (600-800°F). The graph shows that it can power up to 30 inches of 14 gauge.

When placed in series (12v/8.3a), the power supply is able to provide enough voltage to push an electrical current through the resistance of smaller gauge wires to achieve cutting temperatures.

With a series circuit, the positive and neutral leads are tied together as a daisy chain.

The only real connection that needs to be created is between the two middle terminals.

The final connection between the positive and neutral leads (outside leads) occurs as the electrical current flows through the hot wire foam cutter.

With a parallel circuit, the positive leads and neutral leads are bundled together. From their respective connection points, they are then attached to the hot wire foam cutter.


DPDT (on-off-on)

At the heart of this circuit is a toggle switch called a

“Double Pole Double Throw (On-Off-On) Toggle Switch”

The purpose of this switch is to isolate the left and right sides of the switch, while activating the top and bottom set of terminals through the middle/common terminal.

While the sentence is a little hard to write and read, the next series of diagrams should help illustrate the point.

When Side A is activated, it directly attaches all positive leads and neutral leads to one another. This therefore places the circuit into parallel arrangement.

Take a few moments and study the wire attachment to the DPDT switch. It is important to note that all neutral leads are attached to one side of the switch, and the positive leads are attached to the other. It is very important that you do not reverse or interchange positive and neutral leads between sides.

Also, not all DPDT switches have ground terminals.

When Side B is activated, it directly attaches the power supply in a daisy chain arrangement to achieve a series circuit. Take note that side B is the only exception when the left and right sides of the DPDT are allowed to touch and/or interchange. The red indicates attachment through the switch or the power supply.

Now visit the video section to see how this power supply is assembled.


On the primary windings or the “input” side of the transformer, you will notice that there are two black wires and two red wires. Depending on what country you are in, these wires allow the user to select either a 110-120v input or a 220-240v input.

110/120v Input
220/240v Input

If you live in a country providing 110/120v input, then you will need to arrange the primary windings (input) in a parallel circuit.

To do this, you will need to wind the red wires together and attach them to the Household-Hot wire. In this design, the Household-Hot will be coming from the dimmer switch.

Similarly the two black wires will need to be wound together, and then attached to Household-Neutral.

If you live in a country providing 220/2400v input, then you will need to arrange the primary windings (input) in a series circuit.

To do this, you will need to start by winding the first red wire to Household-Hot. In this design, Household-Hot is coming from the dimmer switch.

Then wind the two middle wires together (one is black and the other is red).

Finally, connect the black wire to Household-Neutral