Frequently Asked Questions

We get a lot of questions about our power supplies here at OhmKat.  This FAQ should answer many of the questions you have.  If you can’t find an answer to your question here, please contact us at

General Questions

Why should I buy your Power Supply?  Isn’t a transformer with PTC good enough?

The transformer with PTC is not a safe approach to use with your video doorbell. Even though it may work okay for a certain period of time, as some positive reviews show, it could potentially result in failure and damage at some point in time. The video doorbell has a software triggered short which allows it to operate across different operating environments and installations. In case of a transient short due to a bug or a delay, the PTC transformer will send excessively high current through the bell, and damage/burn the bell. The PTC transformer needs time to get up to a disconnect temperature. This review posted to Amazon is an example of what could potentially happen:

OhmKat power supply ensures that under all operating conditions your bell remains protected. 

What is your warranty policy? 

We stand by our products and we offer a Lifetime Replacement Warranty.  If your Power Supply does not function or fails to meet your expectations, we will help you fix the issue, offer you a replacement or refund your purchase price. 

How long is the cord?

The standard cord length for all OhmKat Power Supplies is 12 ft.  The cord is 6 ft. from the transformer to the split connection, and 6 ft. from the split connection to the video doorbell.  You can safely extend the length of the Power Supply without any loss of performance.  We recommend one of three ways.  First, we sell an extension wire for the section between the  split connection (purchase here).  Second, you can use a standard extension cord or surge protector to extend the distance from the outlet.  Third, for long runs, you can purchase 20 gauge doorbell wire and connect it to our  transformer wire.

Can two extensions be used without affecting performance?

Yes, you can use two extensions. The length of the wire does not affect performance.

Can this adapter work with 220-240v power outlet?

We offer specific transformers for 230v outlets.  Our 230v transformers come with an EU plug.

Why won’t my doorbell connect to the wifi?  Doesn’t your Power Supply provide enough power?

Our Power Supplies do not affect the wifi connectivity.  If there is an issue with the video doorbell connecting to wifi the issue is with the wifi signal itself.  However, if your video doorbell is not receiving a strong enough signal, the app will not have accurate information about the bell’s operating status. Please check the distance to your wifi transmitter as video doorbells need a strong signal to operate. 

Will this work with my door bell wires?

The OhmKat Power Supply is designed to work without doorbell wires. If you have doorbell wires, and they are functional, you can install your Video Doorbell directly. If there is an issue with the installation, you can always use an OhmKat Power Supply later.  Make sure you do not connect a Power Supply and doorbell wires simultaneously.  This could damage your video doorbell.

How do I connect this to my doorbell so my doorbell rings?

Our Power Supplies are designed for situations where there is not currently a doorbell.  If you have a doorbell, you should not need our Power Supplies.  However, we understand that sometimes people have trouble installing a video doorbell with their existing doorbell wires and then purchase our Power Supply.  In this instance, it is very important to not connect your existing doorbell wires and our Power Supply to your video doorbell simultaneously.  This could damage your video doorbell.    

We also now offer a wireless chime that integrates with all our power supplies.  It is an easy plug and play installation.

Even without a chime you will receive notifications of people at your door through the app on your phone. 

I have a doorphone and my existing doorbell is connected with phone cable. Will the phone cable carry enough power to run my video doorbell from this power supply?

Our power supply is designed to plug directly into an electrical outlet. It is not designed to operate over a phone line, which does not have enough power without independent electrical power.  However, if you have an outlet near the inside of the door, you should be able to easily install your video doorbell using our Power Supply.

I don't have an easy way of getting power to my front door, is there a way to plug this unit into a usb battery?

We have not designed our power supplies to plug into a usb battery.  They are designed to plug directly into an outlet.  The length of our Power Supplies is 12 ft.  If your installation location is further away from an outlet, you can use an extension cord, or purchase our extension wire.

What is the power rating of this? what voltage and wattage? The Power Supplies have specific capabilities and tolerances depending on the type of video doorbell you purchased.  We tested all our power supplies extensively across the entire operating power range and they provide a good margin of safety across all operating conditions. There have been thousands of hours of reliable field operations for all units.  This is a complete power supply that does not need any additional resistors or other components. 

Can this be plugged into an outside outlet? Is there any weatherproofing?

It is not designed for open exposure to the elements. Ideally, the section from the small box to the transformer should be protected from the elements.  We are working on a solution to this problem as we get the question regularly.

Can I wire this unit directly into 110v wiring without using the plug into the wall? I'd like to strip the wires and wire it in directly.

No, we have not designed our Power Supplies for that use. The transformer is an integral part of the power management.

Ring Video Doorbell and Ring Video Doorbell PRO

I have a Ring PRO but purchased a Power Supply for the original Ring Video Doorbell.  Can I use it anyway?

No! Do not use the Power Supply for the incorrect unit.  It will not work.  Please return the Power Supply and we will send you the correct version.

Why isn’t my Ring PRO working?  What is wrong with your Power Supply? 

The Ring PRO is a very sophisticated and feature packed video doorbell.  Lots of people love its functionality.  However, in working with many customers, we have discovered some potential issues with the Ring PRO that may cause it to not work as expected.  Most importantly, a small percentage of Ring PROs do not function properly upon installation.  Sometimes they work for a short period of time and then stop.  Other times they get slightly hot or show insufficient power.  These are issues unrelated to our Power Supply.   

If you have an issue with your Ring PRO, please let us know and we will work with you as best we can.  However, also understand that the issue may be with the Ring PRO itself and you may have to exchange it for a different unit.  Before you consider that option however please go through the following checklist:

  1. Did you purchase the correct Power Supply? Please check to make sure you have the correct model.  The Ring PRO will not work if connected to the Power Supply designed for the original Ring.
  2. Does the outlet have power? Plug a lamp or another device into the outlet to ensure it has power.  Sometimes the issue is simply that a light switch was turned off by accident.
  3. Are there any loose connections? The wires need to be securely attached to the Ring PRO. Please remove it and reinstall, double checking that the wires are securely attached to the screws and that the Ring PRO clicks in securely.
  4. Is anything else, such as the Pro Power Kit, connected to the bell? If so, it will not work. The Power Supply should be the only thing connected to the Ring PRO.
  5. Did you select the “No Chime” option upon installation? Selecting the wrong mode may cause the Ring PRO not to work.  If you are not sure, please reset the Ring PRO and restart installation, being sure to follow the instructions provided with your Power Supply.
  6. Was the Power Supply inadvertently shorted during installation? This may happen if it was plugged in prior to installation and the wires touched. Please let us know and we will provide a new harness.
  7. Was the button on the Ring PRO pressed for 10 seconds or more? Doing this may cause a short.
  8. If you have a multimeter, please check the power output. Let us know what you find and we will guide you through the issue.

Answering these questions will help us troubleshoot and solve your problem. If the issue is with the Power Supply, we will provide a free replacement.  However, if the issue is with the Ring PRO, you may need to exchange it.

Will this keep the doorbell charged so if there is a power outage or something similar it will default to battery power?

Yes, however this only applies to the original Ring Video Doorbell as other units do not have independent batteries that can power the doorbell without electricity. 

Does this product negate the need for the Ring Pro-power cable?

With this product you do not need the Ring Pro Power Cable. The Ring Pro Power Cable is for use with an existing doorbell transformer.

The OhmKat Video Doorbell Power Supply is designed for situations where you cannot or do not want to use an existing doorbell transformer (i.e., you do not have a doorbell). When using the OhmKat Video Doorbell Power Supply, you no longer need to power the Ring with doorbell wires, and instead connect the Power Supply to the Ring and plug it directly into an outlet. It is a great option for those people who do not have a doorbell or are having issues with an existing doorbell and no longer want to use it.

I connected this device to my doorbell pro but in the device health it states poor voltage... any way to fix this?

The key is the white light ring on the unit. If it is lit, then it is getting the correct power. The power supply has been tested thoroughly to power the Ring under all operating conditions. The Ring app often provides a finicky indication of poor voltage. It may change during the day to good or very good. If your Ring is working, the Power Supply is doing its job well regardless of the voltage indication in the app.

How come my power supply is not charging the ring video doorbell at all?

The Ring PRO doesn't charge as it doesn't have a battery.  If you have an original Ring, it charges it slowly, like a trickle charger.  Over time it will charge the battery and maintain a full charge once fully charged.

According to the Ring website a 25 to 30 ohm, 20 to 50 Watt resistor is required with the transformer. Is the resistor included in this package?

This is a complete kit. It includes all components necessary to power your video doorbell. No additional resistor is required. However, please be sure to purchase the correct Power Supply as the electrical requirements of each doorbell is very specific.

Will this work on the Ring stick up cam?

Sorry, but it is not currently designed for the Ring Stick Up cam. But thank you for the suggestion. We are looking into it.

Will this charge/work with the Ring if it is not powered all the time (I want to plug it into an outside light that is only on a few hours a day)?

 It really depends on how long it is plugged in. The good news is that the hours you have it plugged in should charge it enough to work for the rest of the day without an issue. If you find that the Ring is not sufficiently charged after a few weeks, leaving the light on for a single day should provide enough charge for several weeks of regular use.

You should never have to remove the Ring for charging which is required without a direct power source.



This seems too good to be true. Is it possible that this could cause fire and I am wondering why would Nest not provide something similar? 

We created these Power Supplies because, like our customers, we did not have an existing doorbell and wanted to install a Video Doorbell.

To ensure safety, we built our Power Supply using high quality, robust components and have tested it extensively under all operating conditions. The Power Supplies we have sold to customers have had thousands of hours of successful field operations. In all the testing and hours of operation, we have not had a single case of our Power Supply causing a fire. The Power Supply will break its internal fuse under any adverse condition and keep the circuit completely safe. Unlike other suggested workarounds out there, our Power Supply is designed to protect the Nest Hello if it inadvertently shorts itself (which sometimes it does). Just using transformers with PTC will not do it.


We can't speak for Nest. All we can do is create a great product that helps customers solve a problem.

My Nest Hello is behaving weird.  What should I do?

When installed correctly your Nest Hello should operate properly.  Often issues that appear to be Nest or power related are due to poor wifi connectivity.

To test for the issue please do the following:

  1. Please cycle your WIFI device (your router and wifi extender if any).
  1. Your OhmKat has unique "One Touch Power Test" capability. Remove the tinned ends from behind the NEST and short these tinned ends while looking at the LED light on the OHMKAT. In 10 seconds or so if the LED distinctly dims out, and then when you untouch the lead ends(it is restored to full bright) and you can repeat this, then your OHMKAT is good and supplying full power.
  1. Once you have tested the OHMKAT, please check for any loose connections. You can check for looseness at the split connection or at the terminal points behind the NEST doorbell.
  1. If 1, 2 and 3 test out okay, then to test the NEST doorbell remove it from OHMKAT ends, and use a micro USB (a typical micro usb adapter) to power it. See if NEST then holds the connection for a few hours, then reinstall.

If you are still having problems, reach out to use at

Nest says I need to use the chime connector.  What should I do?

In a normal installation with a traditional door bell, yes, you will need the chime connector (the white disk that comes with the Nest).  However, we have built the necessary protections into our power supplies which makes the chime connector redundant.  For installations with our power supplies, please connect the Nest Hello directly to the power supply and plug it in.  It is that simple.


 Will the chime work with 230v?

Yes, the Chime is dual voltage. It can be plugged into either 110 or 240V. The plug is a US 2 pin plug, so depending on the region you want to use it in, you will have to use an appropriate adapter but the adapters are easy to find.

 Can I buy more than one chime to work with my video doorbell?

Yes, you can pair as many chimes as you like to a single video doorbell.  Here are the pairing instructions:

 Please plug in the second non-paired receiver into a socket. With the sender plugged in at the split connection, do the following.

  1. Select the melody on the receiver using the button on the side of the receiver.
  2. Then press and hold the volume button(other button on the receiver's side). DO NOT KEEP IT PRESSED FOR MORE THAN 5 SECONDS as this will wipe the pairing.
  3. Press the Nest doorbell button so that the sender sends a pairing communication to the receiver. You should hear the chime Ring. Just make sure that in Nest App chime setting is on.
  4. Repeat 3 if not successful. Once it rings, it is paired.
  5. Once paired both receivers will ring when the Nest bell is pressed. You can set receivers to independently different melodies.

Let us know if you face any issues.