Don't Overload Power Strips!

March 2017

Multiple outlet power strips (surge protectors, temporary power taps, plug strips, etc.) are commonly used in both office and lab areas. These are designed for low power loads such as computers and similar electronics.  In the event that high-current devices such as space heaters, microwaves, toasters, ovens, and pumps are plugged into a power strip, overloading can occur resulting in tripped breakers or even electrical fires due to overheating.

The following precautions must be followed when using power strips:

  1. Power strips must be listed by a Nationally Recognized Testing Laboratory (NRTL). A logo such as “UL” or “CSA” is commonly found on the data plate.
  2. Multiple power strips must not be “daisy chained” together or used with extension cords.
  3. DO NOT exceed the load (ampacity) rating of the power strip. Most 120-volt power strips are rated at a maximum cord and plug load of 12 amps. Most appliances and lab equipment list the wattage and voltage on the data plate. Use the following equation to determine current load (amps):

          I = current (amps), P= power (watts), E = voltage

Just a few large appliances plugged into a power strip will easily exceed its maximum load. For example, a 1300-watt toaster and a 1,100-watt coffee maker have a combined load of 19.8 amps. This greatly exceeds the power strip load of 12 amps.

  1. High current equipment such as space heaters, microwaves, refrigerators, ovens, pumps, and furnaces should be plugged directly into a wall outlet.
  2. If a power strip is damaged or shows evidence of overheating, take it out of service immediately.

If you have any questions about use of power strips, contact the ETA Safety Manager, Ron Scholtz X8137 or the ETA Electrical Safety Officer (ESO), Ari Harding X2566.