Contactors vs Relays

Contactors vs Relays

August 26, 2019

The terms relay and contactor are often used interchangeably when people discuss electrical systems. However, there is actually a difference between the two, and it’s important to understand why so that you can make appropriate decisions concerning your electrical maintenance. At Mr. Electric of Dallas, we enjoy helping local North Texas home and business owners improve the safety and efficiency of their electrical systems. Are you interested in learning more about contactors and relays? Then this is the article for you. 

Open or Closed Contact

A contactor almost always uses open contacts, whereas relays will utilize both Normally Open or Normally Closed, depending on its purpose. If you’re using a de-energized contactor, then there isn’t a connection. However, with a relay, a connection might remain.

Load Capacity

A contactor is capable of handling loads greater than 10A, while relays can normally only carry 10A or less. 


Contactors usually carry high electrical loads, so they frequently come with bonus safety features like spring-loaded contacts and arc suppression. In addition, many contactors will also be connected to overloads, which interrupt circuits if a current exceeds a specific threshold. This helps keep the equipment safe from damage from electrical currents. While some relays will have overload protection, most do not. 


Relays are normally only used for single phase purposes and are rated for 250V maximum. In contrast, contactors can be used in 3-phase applications and are rated for as much as 1000V.

Why Do Contactors and Relays Matter? 

Circuits can be overloaded if they aren’t using the appropriate equipment. Therefore, a relay should only be used when the current is less than 10A, with 250VAC on a single phase. If your electrical needs require more than that, then it’s vital that a contactor is used instead. Most property owners are not aware of whether they are using a relay or contactor. However, if you are experiencing frequent problems with your electrical circuits, there are many factors to consider. Be sure to call a trusted local electrician in Dallas so you can ensure that your electrical components are properly installed and in working order. At Mr. Electric of Dallas, we offer professional inspections for DFW area homes and businesses. We also offer emergency repairs and replacements if necessary. 

Need a Certified Electrician in North Texas? Call Mr. Electric of Dallas Today

Are you having issues with your circuits or wiring? Then call the experts at Mr. Electric of Dallas. Our team of certified, licensed and insured experts are always ready to lend a helping hand. We proudly offer a wide range of commercial and residential electrical services including electrical system installation, wiring upgrades, circuit repairs, panel box replacement, lighting system installation and more. Our local electricians provide quality, dependable services in Dallas, North Dallas, Lakewood, highland Park, Farmers Branch, Inwood, University Park, Coppell, Irving, Oak Lawn, Arlington and surrounding DFW cities. Contact our office to learn more about our offerings or to schedule a convenient appointment with a licensed plumber near you.