extension cords dangerous to plugin together

Plugging Two Extension Cords Together is Dangerous! Here’s Why You Can’t Attach Two.

AllumiaX Engineering
2 min readApr 22, 2019


Extension cords enable us to deliver power where needed. However, an extension cord is just a temporary solution, and should not be used as a long-term extension of your household’s electrical system.

Extension cords are designed to carry a certain level of current over a fixed distance which is the length of the cord. Once you have two identical extension leads connected in series, one after the other, the extension cord’s resistance effectively increases. This results in greater heating of the cord and possible damage to the insulation, which can be the source of fires and electrical shock.

Problem Arises When Joining Two Extension Cords

Another problem with interconnecting plug together arises when the cords become loose and pull apart, resulting in loss of power. There is also less current available to the load in this arrangement, so a fault that occurs far away from the source may result in the breaker failing to trip.

Using extension cords properly is critical to your safety. The Electrical Safety Foundation International (ESFI) offers a set of tips related to the use of extension cords for staying safe from electric shock and electrical fires.

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What’s Wrong in Attaching Two Extension Cords?

Assuming each extension cord is correctly rated and protected, once you have two identical extension leads in series, one after the other, the combined lead will experience a voltage drop per unit length and also increases the overall resistance of the two cords.

Read on to learn about safely using extension cords for a specific period of time.

Let us know if you have any queries regarding this topic and do provide us with your feedback in the comments.

About The Author

Abdur Rehman is a professional electrical engineer with more than eight years of experience working with equipment from 208V to 115kV in both the Utility and Industrial & Commercial space. He has a particular focus on Power Systems Protection & Engineering Studies.

Abdur Rehman is the CEO and co-founder of allumiax.com and creator of GeneralPAC by AllumiaX. He has been actively involved in various roles in the IEEE Seattle Section, IEEE PES Seattle, IEEE Region 6, and IEEE MGA.



AllumiaX Engineering

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