A covered cord does not allow heat to escape which could result in a fire. If your extension cord happens to be a spiral type board, always unravel the entire cord and use it even though the distance to the power source may be a short one.
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Using more than one appliance may cause additional load on the extension board making it heat up and catch fire.
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Heavy reliance on extension cords means that your home has too few power outlets to meet your consumption. Arrange an electrician to install additional outlets wherever needed.
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