All junctions must be accessible in a box according to the electrical code, so you'll surely need one here. You have two options (that I am aware of): make a huge hole in your siding or put a retrofit light box into the wall hollow. These are called "security boxes" and require a permit from your local building department.
The easiest way to comply with this requirement is to use a security device from GE. They come in a variety of styles and prices and can easily be installed by anyone who knows how to turn off the power at an outlet. The light will stop working if it's not in a security device because that means electricity is flowing into dead space under the siding. Such space cannot contain electrical wiring or devices so they must be protected by a security device.
There are other options for remote-controlled lights on doors or windows. These work fine as long as they're not also used as interior lights, which they usually are. If they are also used as interior lights then they violate the circuit requirement that only one bulb serve as a backup for each location where a doorbell button is located. This would mean that only one window could be opened from inside the house without breaking the law.
Remote-control lights allow you to open both doors from the outside while still giving the appearance of only having a left side door when there is no one out front.
Choose from a variety of junction box sizes to get the one that is right for your project. It's ideal for exposed interior applications like conduit in an unfinished basement. These boxes are affordable and simple to set up. Electrical boxes made of plastic can be installed beneath walls. They're lightweight and easy to install using screws or adhesive strips.
The best option for a basement finish project is a metal box with heavy-duty connectors. These can also be used inside walls if you want to hide the wiring within the wall. The advantage is that you can cut any size hole into the wall without having to worry about breaking a cable.
Concrete basements are usually finished with drywall over wire insulation and covered with paint or wallpaper. The type of box used depends on how the wiring is going to be accessed later. If the wires are going to be accessible but not readily visible, then use a metal box with wire holes large enough to fit a hand. This gives you room to work with when installing new circuits or trying to find a broken cable.
If the wiring is going to be visible all the time, then you should use a metal box with drywall cover plates. You can find these boxes at home improvement stores. They're designed to look like wood paneling and come in a wide variety of colors.
The last option is a plastic box with wire holes large enough to fit a hand.
A light fixture cannot be installed without a junction box, unless the fixture has its own junction box. The simplest way for installing a light in an interior space where there is no box is to install a remodel box. Install a waterproof surface-mount unit in outdoor areas. Then, either remove the faceplate or cover it with a shade. Finally, connect it to the existing wiring inside the house. You will need to use color-coded wire to connect the black and white wires together and then connect them to the hot terminal on the surface-mount box.
Installing a light fixture without a junction box can be dangerous because you will not have the protection of a breaker if something goes wrong. Also, any exposed metal parts of the light fixture can cause serious injury if someone touches them.
The National Electrical Code requires that all circuits containing lighting equipment be protected by a circuit breaker or fuse panel. If you are not sure if your home was built with breakers, call your local utility company before you start work on your lights. They should be able to tell you if your home is up to code and help you determine what type of protection is needed.
Lighting is one of many things that can cause damage to your home if not done properly. If you are not sure how to safely work with electricity, hire a professional electrician.
The quick answer to the question of how to install a light fixture without an electrical box is that you don't. The electrical box, also known as a junction box, is a regulatory requirement designed to prevent fires and other electrical catastrophes. But it can be difficult or expensive to find parts that will fit into a fixture without first installing some form of electrical box.
The easiest way to install a flush-mounted ceiling light is by using a kit that includes all the parts you need (pictured below). These usually include the frame, glass assembly, and ballast all in one package. You just have to supply your own screws. Ceiling lights are available in a wide variety of styles and sizes and can be hardwired into the wall with ease. If you want to replace a standard lamp holder with a ceiling light, this is simple enough. Just buy a new one that fits your new light, attach it to the wiring inside the old socket, and you're done. Replacing a fluorescent tube fixture with a compact florescent replacement tube is similar. You'll just need to make sure that you don't exceed the capacity of the current breaker before making any changes.
If you don't have access to these types of kits, there are several different ways to install a ceiling light. One option is to use self-contained fixtures which can be installed directly into the drywall at any height.