quote; When I was working with my father one time, a 110-vac receptacle was used to plug in some equipment at a customer's location which promptly burned up. It turned out someone had intentionally wired it for 220 and not changed the receptacle. I thought there might be some recetpticles also out there that could be wired for one of two differnt voltages and the blades changed to make it correct......
These are specialized situations where someone CREATED, or can create, an unsafe condition because they disregard safe practices. When that happens there is NO WAY to detect it without testing, but in the normal situation, you can usually depend on the receptacle being wired for its intended voltage and usage. I was once working on a commercial site. When I asked where there was a 120 volt receptacle, the fire sprinkler guys said, "right there on the wall". I looked at it and told them, "It may be a 120 receptacle but it is 240 because it is painted red". They told me it was impossible because they had been using it for their power vise for two weeks. I called the electrician over and asked him what the voltage was. He said, "240", to which the sprinkler guy said, "No wonder my vise has been running so fast. I was getting pipes threaded in half the time it usually takes."
If you KNOW what you are doing, and have some special need, you can wire almost ANY recepacle the way you want to, as long as you also wire the male plug the same way. I use a 20 amp receptacle and an "opposed" prong plug for a foot switch. The opposed prongs prevent the switch from being inserted into a standard outlet which would blow the breaker as soon as you stepped on the switch.
Last edited by hj; 06-11-2011 at 09:12 AM.