Extension Cord Polarity

A polarized power cord has prongs of different sizes.

Extension cord polarity. Lamp cords with pre molded plugs can be readily had from a proper electrical supply mcmaster carr or by hacking an extension cord of appropriate gauge typically 18 awg unless it s one heck of a lamp. Check the polarity and continuity between the plug and the jack. Some three prong plugs are also polarized and when they are the same rule applies. On a polarized grounded cord the smaller prong connects to hot and the semi rounded pin underneath the two prongs connects to ground.

The hot wire is always smooth on the outside of the cord while the neutral wire is ribbed on the outside. On cords of this type the larger prong connects to the neutral wire. Polarization is a way of making sure a switched light or appliance isn t energized and can t shock you when the switch is off. Check the voltage and polarity at the extension plug before use.

Use cords that are white translucent yellow brown or black avoid obvious i hacked an extension cord colors like dark green. Feel the other wire which is smooth. If the end has one prong larger than the other the larger one is negative. Strip the insulation off the wire by cutting and pulling the wire through the wire stripper.

A nonpolarized power cord has prongs of the same size. Connect the extension cable to the power supply and plug the power supply into an ac outlet. For flat cords with polarized plugs on the end the larger prong or terminal is the neutral wire. Make sure there are no signs of shorting.

The 16 gauge wire is rated to carry 13 amperes up to 1560 watts as compared to the formerly used 18 gauge cords that were rated for 10 amperes up to 1200 watts. Lamp and extension cords are usually 18 gauge but if you re not sure strip the wire through the 14 or 16 gauge slot first. You can only use a polarized plug with a polarized outlet. Perhaps the most common damage comes from pulling out the cord by the cord not the plug.

Eventually this stretches out the cord wires and separates the sheathing or outer jacket from the plug exposing the cord wires. If you have a wire where both sides are the same color which is typically copper the strand that has a grooved texture is the negative wire. If there is one side of the wire that has writing on it that is likely negative. Extension cords can be damaged in many different ways from dragging then along the ground to running over them with vehicles or closing them in a door.

Slide and screw the plastic sheath back into position. The larger prong connects to neutral. Flat cords that have only two wires such as those used in most lamps are not marked by colors. To prepare the cut end for a new plug cut or pull the two sides apart then strip off about 3 4 in.