How to Calculate the Amp and Power Load of LED Lights

Step	Formula	Example
Find current	Amps = Watts / Volts	300W / 120V = 2.5A
Add fixtures	Total amps = amps per fixture x quantity	10 fixtures x 2.5A = 25A
Check continuous load	Continuous load <= breaker amps x 0.80	30A breaker x 0.80 = 24A max continuous

The load and capacity of your electric transformer becomes vital for numerous reasons when adding new electrical devices including luminaires, the fancy word for light fixtures. If you are considering adding new lighting, then the load planning task is quite important. For a one for one LED Light replacement, the task is quite easy as you know your AMP and power load will go down. (unless you are using LED Fixtures with higher wattage than current draw) 

 Understanding the load needs of your building will enable you to choose an electrical setup with an appropriate size.  It is very typical for the transformers to be undersized and poor in older homes and businesses.  However, before diving into the nitty-gritty of calculating amp load or electrical load, let us try and understand what a circuit breaker and amp load exactly are!

Now, let us move on towards the facets of a circuit breaker and circuit breaker load. A circuit breaker is a device that intervenes with the abnormal or faulty current. In other words, it is a device that disrupts the flow of high magnitude current and performs the function of a switch. A circuit breaker is fashioned to close or open an electrical circuit and protect the electrical system from damage. It is unsurprising that, like other electrical appliances, a circuit breaker can also malfunction and cause numerous problems in case of an overload. As such, the power of your home can be dismissed for several hours. Therefore, it is crucial to understand that the load a circuit breaker will be handling is manageable and doable. So, we need to understand the amp load and ensure that it is balanced. 

The term amp load is used to indicate the power you get from the main electricity source or transformer.

Amperage is the official term used for the measurement of the total electrical capacity, as such the name – amp load. In older homes, the electrical service usually delivered 30 to 60 amps. Homes built after the 1960s commonly carry 100 amp service, and most modern and spacious homes have 200 amp service installed, which may even extend to 400 amperes. 

If you are keen on calculating whether your electrical services are sufficient, you must calculate the amp load. It needs mathematics calculations and a lot of zeal. 

 

To begin with, it is crucial to recognize that calculating the amount of power that you can use depends on the amperage load of different fixtures and electrical appliances.  That is depending on the voltage. 

Example:  a 300 watt fixture / 120 volts = 2.5.  So we know that it needs 2.5 amps of capacity.  In a 240 volt setup the divisor is double so we know it's half, or 1.25.  It looks like this: 300/240=1.25

You can see how even 10 of these 300 watt fixtures is 3,000 watts and still only 12.5 to 25 amps depending on voltage.    on a 30 or 50 amp breaker you still have lots of room.  

PRO TIP: The load must not be higher than 80% of the total electricity capacity. 

The above formulas can help you find the capacity of the electrical service. 

We can also use the Amps x volts formula to figure out the electrical services of the residential as well as commercial buildings. Considering that a home’s primary electricity service is 120 volts, then the total would sum up to –

LED surge protectors;  one of the jobs of a breaker is to 'trip' in order to prevent damage to devices, fires or other problems.    A lower lighting load is good for energy use, but it does not replace surge protection. A breaker is sized to protect conductors from overcurrent; it is not a fine surge filter for LED drivers. Lightning, utility switching, and dirty power can damage LED fixtures without creating the kind of sustained overcurrent that trips a breaker. For outdoor lighting we recommend you add surge protection.  For outdoor pole lighting its almost required to have whole breaker surge protection.   At $200-$500 its cheap insurance against major failures that are often not covered by warranty.  

At this point most LED light retrofit users are done and can get on to install, but for those needing more we'll look at Electrical load.

You now know how to calculate the capacity of individual circuits so we'll now review a larger full building’s electrical service. At first glance, it may seem as simple as calculating load is all about totaling the electrical load of the light bulbs, fans, heaters, and other appliances of your house and then comparing them to the total capacity of your electrical service. Well, it's anything but easy.   You can measure the load by simply adding up the wattage ratings of various fixtures and appliances of your home that are extracting power simultaneously. But, we tend to forget that we don’t use all our hard-wired devices simultaneously. It is highly unlikely for all the light bulbs, fans, ovens, toasters, heaters, and coolers of your house to run simultaneously. As such, professional electricians opt for alternative techniques to calculate the load. We have cataloged a few popular uses by experts to determine load.

1. Getting the total of the wattage of fixtures and individual branch circuits

2. Adding the wattage rating of all permanent appliances such as dryers, water heaters, and so forth

3. Subtract 10000

4. Multiply whatever figure you get by 0.40

5. Add 10000

6. Get the wattage rating of air conditioners as well as heating appliances. Add the larger numbers of the two. It is noteworthy to mention that we don’t add both the numbers because we don’t heat and cool simultaneously. 

7. At last, divide the total figure you get by 240

As per electrical experts, a 100 amp electrical service is extensive enough to power most residential circuits;  a 200 amp transformer is good for homes and buildings above 5,000 square feet or maybe where solar panels are installed.   A 300 to 400 amp transformer is necessary for buildings that are more than 35,000 square feet. We highly recommend upsizing the service when the heat load goes beyond 5,000 watts. 

To conclude, we can understand the various facades of amp load, a circuit breaker, and a circuit breaker load. It is noteworthy to mention that LED lighting plays a massive role in easing the burden from your primary electricity service and balancing the load. Therefore, LED lights lower the risks of overload, risky power cuts, and appliance failure. If you are interested in saving energy, it's time to go LED