How Many Amps Does a 1000 Watt Ballast Use? [a Short & Sweet Answer]


Written by

Thomas Carter



Marcos E. Williamson

how many amps does a 1000 watt ballast use

When getting a 1000-watt ballast for different applications around the home, you might want to know “How many amps does a 1000 watt ballast use?”

The answer depends on the voltage of the system it is wired to. For example, when connected to a 120V system, it would draw about 8 amps. In a 240V system, a 1000 ballast watt would use roughly 4 amps.

So, the amp in 1000 watt ballasts is calculated using the formula Amps * Volts = Watts (with 1000 going into the Watts variable).

But there is more to know about this topic of 1000w to amps. Continue reading to find out all the details!

How Many Amps Does a 1000 Watt Ballast Use?


How Many Amps Do I Need?

This depends on your required input voltage. If your setup is 1000W 120V, then you will need 8 amps. If your voltage is 240, you will need only half as many amps (4 amps). So, the pattern is the higher the input voltage, the lower the amps needed.

However, it is important to note that this can vary depending on the efficiency of the ballast and other factors like voltage fluctuations. Electronic ballasts, for instance, are often 100% or 88% efficient, while magnetic ones use 12% more power in comparison.

How to Calculate the Amps Drawn?


As mentioned in the introduction, there is a formula that we can use to compute the amps that a ballast draws when wired to a certain voltage system. The formula is Amps * Volts = Watts.

Let’s say we have a 220V system. We would plug 220V into the Volts variable and 1000 into the Watts variable to get Amps * 220 = 1000.

From here, we would get the Amps itself by dividing 1000 by 220. We would be left with around 4.5. Hence, the answer to, “How many amps does a 1000 watt ballast draw from a 220V system?” is 4.5 amps.

Tips to Find the Right Ballast


There are a few different factors that you must take into account to pick the right ballast ffor your needs.

  • Input Voltage: Look at the accepted range of volt your ballast offers. If the ballast that you are eyeing cannot support the input voltage you have, then you will need to look for a different ballast or change your wiring/outlet.
  • Bulb Type: This is more important if you are considering older makes of ballasts. They are usually only compatible with a metal halide lamp or an HPS light.
  • EMI (Electro-Magnetic Interference): Ballasts with low EMI will not interfere with your other electronic communication devices, wifi, and cables. That said, you probably won’t need to worry much regarding this area when shopping, since the US only permits sale of devices with acceptable interference.
  • Ballast type: Some ballasts have watt selectors that allow them to run several bulbs up to 1000 watt lights, and a few can reach 1150 watts. Magnetic ballasts also tend to be more affordable than electronic ones.
  • Circufit Breaker: Ballasts with built-in breakers are typically preferable. They can help you avoid hot restrikes and limit damage to your lights.

Frequently Asked Questions (FAQs)


How many amps does a 1000 watt led light draw?

It would draw a bit more than 8 amps (8.33) when wired to a 120V system and slightly over 4 amps (4.17) when connected to a 240V system.

How many ballasts per light fixture?

This varies from fixture to fixture. Some have several tubes and a ballast for each tube. But some have two built into one case tube.

What is the electricity cost for a 1000 watt grow room?

The specific cost depends on the type of grow light you use, how long you run it, and your local energy cost. Remember that electric companies charge by kilowatt hours, not by amps or volts. A 1000W system running for 1 hour will cost 1 kilowatt hour.

If we use the average US electrical rate, that’s 0.148 dollars per hour.

How much does a 1000 watt HPS draw?

It draws 9 amps when connected to a 120V system. You can use this as the reference number for calculating the amp draws with other voltage systems.


So, to wrap up this short blog post on “How many amps does a 1000 watt ballast use?” a 1000 watt ballast typically uses around 8.3 amps when running at full power. But this can vary depending on the efficiency of the ballast and other factors such as voltage fluctuations.

It is always a good idea to check the specifications of your specific ballast to ensure that you are using the correct amperage. Additionally, it is important to make sure that your electrical circuit can handle the requirement of your ballast to avoid any potential safety hazards.

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