A double male cord is unsafe because it leaves a male cord cap with 115-volts exposed to kill somewhere in your home. Touch it with wet feet and it will be nice knowing you.
From now on, plug in your lights to test to see if everything is working, and then hang them up with the power off, (in case there is a loose wire that could shock you). This way you won’t hang them up backwards again. Plus it’s a lot easier to repair a dead bulb or two when the strings of lights are on the ground.
Why is one of the two plug prongs on my lights and extension cords larger?
The reason one of the prongs on all-new extension cords and electrical appliances are bigger is to polarize the appliance. If all plugs, extension cords, and appliances are properly polarized the chances of an electrical shock are greatly minimized.
In normal house current, one of the wires is normally safe, the white wire. It is the wire that is connected to the ground rod and the cold-water plumbing. This means that when you touch it, you and the earth are the same, hence no shock.
This rule is by no means always true. There are switch leg situations that use the white wire as a ‘hot’ wire. There is also the ‘untrained’ who could have switched the colors of the wire in a circuit box prior to your location. The point here is that ‘nothing is always’, a favorite quote at the store.
The black, ‘hot’, wire is potentially 115 volts opposite of the ground. Grab it and the electricity will flow through you and into the ground. The black wire that is switched, fused, and connected to the smaller slot of the two prongs of a receptacle. Why the little slot? It is the one that is harder for children to poke metal objects into.
In a lamp, the hot wire is connected to the base of a light socket. This makes changing light bulbs safer because your finger will have to get to the bottom of the lamp socket to receive a shock.
Always kill the power before working on any electrical items. Working with live electrical wiring is best left only to the professionals. We don’t want to lose any customers to careless wiring accidents. Electricians’ rule: keep one hand in your back pocket.