A junction box sits between the main power lines and the house. It is smaller than a terminal box. More importantly, you can expand the box’s role to house additional connections down the line.
They differ from terminal boxes, which hold specific connections. Many people assume that transformers and junction boxes go hand in hand because contractors are always trying to conceal transformers. But that doesn’t mean you should pair these two devices.
Can You Put A Doorbell Transformer In A Junction Box?
So long as you keep this device outside the junction box, you should be fine. And if you must install the transformer in a junction box, don’t forget to separate the high and low-voltage wires.
The junction box is a convenient solution because it keeps the transformer out of the way. If you want to hide the device, the box will do that for you. However, it can also lead to overheating, especially if the junction box is small and doesn’t have vents. This is why many contractors prefer to mount the transformer on the side of the box.
Many junction boxes have exterior features that accommodate transformers. Additionally, installing a transformer in a junction box allows high and low-voltage wires to come into contact with one another.
The transformer is connected to 120V wiring from the service panel. However, it uses 24V wiring to take power to the doorbell button. You can insert a barrier to keep the wires separate. You should also provide sufficient insulation. But it is safer to use the knockout, leaving the transformer and its terminals exposed.
Some people dismiss overheating as a significant threat because doorbell transformers are rarely in use. However, many local authorities prohibit the installation of transformers in junction boxes because they can create heat while idle.
1). What Does The Transformer Do?
A doorbell is a low-voltage device. They cannot withstand the 120 or 240 volts you find in a conventional homestead. The transformer steps the voltage down to protect the doorbell. Finding a transformer in a house is challenging.
You need to follow the wires from the bell to locate the device. This may take you to the attic or the basement, depending on your setup.
2). Mounting The Transformer
You can start your search for the transformer at the service panel or breaker box. But you don’t have to look inside. People mount these devices on the exterior of the junction box. The transformer’s front terminals are exposed, but they are not dangerous because their voltage is low. They present a low electrocution risk.
3). Can The Junction Box House The Transformer?
Yes, it can. Or, at the very least, no one will stop you if the installation is in a residential setting. However, you may not pass an inspection, depending on the laws in your region. Your biggest concern is the size. Is the junction box big enough to accommodate the needs of the transformer?
Many junction boxes are too small to house the transformer. But technically speaking, you can install the transformer in most locations in a house.
4). What About The Doorbell Transformer Cover?
If your objective is to hide the transformer, use a cover. Foter has covers in various shapes, sizes, and colors. You can find a cover that matches your home’s decor. This option is safer than a junction box.
What Does The Code Say About Installing Doorbell Transformer In Junction Box?
The National Electric Code prohibits contractors from installing low-voltage wiring in a panel, conduit, or box that houses high-voltage circuits. Therefore, placing a transformer in a junction box is a bad idea.
But the NEC doesn’t have the final say. Check your local code. If it permits the installation of transformers in junction boxes, you can go ahead.
Where Else Can It Be Placed? Should I Hide It In Box Or Place It In an Open Location?
You can install the doorbell transformer wherever you want. That includes open or exposed locations. Transformers are low-voltage devices. They do not pose a significant threat to homeowners.
That being said, it is more convenient to place the device near the circuit breaker because this gives you easy access to high-voltage wiring. You can also install the transformer near the chime. People don’t hide transformers because the code demands it. They hide these devices because they are unsightly.
Occasionally, you find them in hallways. But most of the time, homeowners keep them in the closet, especially in homes with cubbies in the closet. If you don’t have a closet in the area, use the garage.
Most garages house inconvenient items such as washers. One more won’t change anything, especially a device as small as a transformer. Look for a place with unwanted electrical components and install the transformer.
Don’t limit your search to distant locations like the garage, attic, and basement. You are more likely to forget the location of the transformer, especially if you go years without tampering with it. If you have to follow the wires from the button to the junction box, it may take you longer than expected to find the transformer.
You are better off keeping the device within easy reach. Identify a location that already has many wires. For instance, if you have a high-end computer or an entertainment system, you can conceal the transformer within the wiring you’ve amassed over the years.
The NEC doesn’t say anything concrete about the location of the transformer. They don’t want you to keep it inside the service panel or raceway with high-voltage cabling. Beyond that, the NEC doesn’t care.
Fortunately, many transformers include instructions telling you where to mount them. Follow these instructions carefully. If the instructions are vague or silent about the location, use the local code for guidance.
If they are also silent about this issue, feel free to install the transformer wherever you want.
If It Is Possible, How Do You Install A Transformer In Junction Box?
Even if the practice is discouraged, you can install a transformer in a junction box using the following steps:
1). De-energize the circuit. Don’t tamper with electrical wires on a live circuit. Use the breaker to kill the power.
2). Find the junction box. If you already have a transformer in the junction box, follow the wires from the doorbell button to find the transformer and its junction box.
3). Remove the cover and identify the 120V wires. If you have an older transformer, remove it. Don’t touch the cables until you check them with a tester. The tester will confirm that the circuit is de-energized. Breakers can malfunction. You can’t trust a defective breaker to shut the power off.
4). Insert the transformer. Use the box’s knockout hole to bring wires into the box. Use pliers to tighten the mounting nut.
5). Put your gloves on. Even if the circuit is de-energized, you are encouraged to take all the relevant precautions. That includes wearing protective gloves before handling the line-voltage wires.
Strip the wires were necessary before connecting them to the relevant terminals. The ground wire runs to the green lead, the neutral wire to the white lead, and the hot wire to the black lead.
Push all the excess wiring into the junction box and slide the cover back into place.
6). Run the low-voltage wires to the transformer’s terminals. You can’t get this step wrong because you can use either terminal. They are interchangeable. If you’re satisfied with your work, energize the circuit and test the bell.
If it won’t work, open the junction box and check your wiring. You can also hire a professional to give the wiring a second look. If the transformer is faulty, get a replacement.