How to Determine Wattage of Light Fixture

How to Determine Wattage of Light Fixture

How to Determine Wattage of Light Fixture

How to determine the wattage of light fixture

How many times have we tried to fix light bulbs in your house? Many times, probably! However, not many of us know the details and the relationship between a bulb and its fixture properly.

This is one of the major reasons why there are fire scares or circuit drops at home when we try to fix light bulbs. If you thought that lights bulbs could be fixed into any empty fixture in your home, you are mistaken.

Every fixture, in a residential or commercial establishment, comes with a maximum wattage capacity. Therefore, when you try to accommodate bulbs more than its capacity into the fixtures, it results in overheating of the unit that may lead to fire accidents as well.

How do you ascertain the maximum wattage of a light fixture? There is always a sticker in a fixture that tells you the details about the maximum wattage it can hold. However, the key is to find out the exact location of the sticker inside or outside the fixture. Here are some fundamental ways that will help you to understand the wattage threshold of a fixture:

Lamp Socket

It may sound simple to people who know how to see the wattage, but it is still an important lesson for people who don’t know anything about the fixture’s wattage.

The first place that you have to check out is the lamp’s socket. Inside the socket, you will find a sticker with a silver shade to it. This sticker will give you the details about the maximum wattage that a fixture can accommodate.

Recessed light fixture

A recessed light fixture is a model that is installed well into the hollow hole of the ceiling. It is not as straightforward as the other normal fixtures when it comes to checking the wattage threshold. However, don’t worry; all you need to do is to see inside the can of the recessed light fixture to know how much of wattage the fixture can accommodate.

Remove the ceiling lights cover

More often than not, you will come to know of the maximum wattage of your light fixture when you remove the cover of your ceiling lights. The wattage sticker can be found easily when you remove the cover.

Watch out for the sockets of the lamps. Sometimes, the sticker can be found on the sockets, whereas on other occasions, the sticker can be found near the sockets as well.

Instruction manual

One of the most common and simple ways to check the maximum wattage of a fixture is to check the instructions manual of the light fixture. It is important that you keep the instructions manual safely when you buy light fixtures.

You can also check the box in which the fixtures were packed when you bought them. This box will tell you the details about the maximum wattage that a fixture can hold.

While these are some of the basic steps that are easy to follow by everyone, what we are going to tell in the following sections is slightly complex.

This section deals with finding out the wattage of a light fixture when you don’t find any details on the stickers or the manuals or sockets. What do you do then? You cannot use any bulb randomly, because you could then be causing a circuit trip in your home.

Understanding the maximum wattage of a bulb when the details aren’t straightforward

In this case, you have to be well aware of one term – Voltage. This is a detail that is provided on every light fixture very explicitly. This is usually represented in the form of a number followed by V. The second term that you have to be aware of is Amperes.

This is the amount of current that the fixture uses. This is represented by a number followed by A. You should then watch out for the term, Resistance. As the name suggests, this term is the opposition that the fixtures offer for the electric current that passes through it. This is represented by a number followed by the Ohms symbol.

The simple formula to calculate the maximum wattage of a light fixture is:

Wattage (W) = Voltage (V) x Current draw (I)

However, it is important to take into account the resistance factor as well when you want to calculate the maximum wattage of a light fixture. So, you can make use of this formula:

Wattage (W) = Square of Current Draw (I) x Resistance (ohms)

In some light fixtures, you will find details such as the Resistance and Voltage details. You will not find any information about the current drawn by the fixture. The formula to use in this case is:

Wattage (W) = Square of Voltage (V) / Resistance (Ohms)


We do understand if the formulae were a bit too complex for you. In most of the cases, you will get the details of the maximum wattage of the light fixture right from the instruction manual.

If you don’t understand any of these formulae, it is perfectly alright. In the case of the wattage details not being readily available, all you need to do is to call an expert electrician to calculate the accurate wattage of the light fixture.

Why is it important to know the wattage of a light fixture? This is because you need to know how much you can load on it, to the maximum possible extent. What happens when you keep blowing air into a balloon even after it has reached its maximum capacity? It bursts!

Similarly, fitting a bulb that has a higher wattage than the fixture, into the fixture can cause overheating, circuit trips and fire accidents, in some cases. Watch out for these issues in your home, because when left ignored, they turn into a huge problem.

If you notice a burning odor or burn marks at the bottom of the bulb, you have to change that particular bulb immediately. If you notice frequent tripping of circuit inside your home after changing bulbs, it means the electric lining in your house has been affected.

Watch out for the symptoms and be alert for slight changes. Change the light bulbs only after ascertaining the maximum wattage of the fixtures, so that you can be safe than sorry.

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