Long long ago I was asked to investigate a situation where there was a house with an external sleepout. If an appliance cord is wired incorrectly, strange things may happen, or it nothing obvious may happen but trhe appliance may become letally dangerous. body then this may be a very very very bad idea indeed. If the metal parts are a toaster or electric jug or vacuum cleaner or. This may affect the ability for house fuses or breakers to operate correctly and WILL trip residual current devices.Īny appliance which has the earthed metal parts connected to Neutral (which they should not have) will have the metal parts placed at phase potential if feed PN are reversed. If neutral and ground are connected within the appliance it will still usually operate but large metal parts connected to ground will now be at neutral potential. In a grounded appliance there SHOULD be minimal effect. In a DI appliance there is minimal effect. Phase and Neutral can usually be reversed at the appliance feed point without causing immediate hazard. Neutral is usually held at ABOUT ground potential but is NOT connected to the ground lead within the appliance. The mains feed consists of two wires - usually termed Phase and Neutral. Systems with resdiual current tripping (named variously ELCB/GFI/RCD) devices can detect very small currents to ground (<= 20 mA) and discnnect the circuit in <= 1/2 a mains cycle. If an electrical path develops between supply "Phase" and the earthed metal parts, ground current will flow and curcuit protection will operate (fuse or circuit breaker). If you eg stand in a puddle while holding it and pour water into it, or use it while in a bath or shower, you may exceed the regulatory conditions of use envelope.Ī safety ground is an arrangement that connects accessible or modestly insulated metal parts of the appliance to system (in this case "usually" house) ground. DI means that the appliance is never electrically unsafe under regulatory acceptable conditions of use. Modern appliances are EITHER double insulated or have a safety ground.ĭouble insulated is more a level of insulation than two physical layers of insulation. In the real world, people do die from this, alas. What sorts of appliances will malfunction or worse, potentially harm someone, if plugged into an outlet that is wired backwards?īadly designed (and thus uncertified) ones. If one prong is intended to be hot, surely it would be a big deal if it is not? It is those appliances in particular that I am concerned about. It seems sensible to me to assume that one prong is wider for a purpose. Wiring codes, require that side of the plug to be wired to neutral, while the shorter side is to be wired to hot. Many appliances with a ground prong obviously go in one way only.īut there are also many appliances with two vertical prongs and no ground prong, but one vertical prong is slightly wider than the other and that is supposed to go into the taller slot (on the left in this diagram). Many appliances have two equal sized vertical prongs and no ground prong so they can be reversed. North American outlets are as shown here: I apologize for not clarifying my locale and its specifics. What sorts of appliances will malfunction or worse, potentially harm someone, if plugged into an outlet that is wired backwards? Obviously lamps and fans will have no issues, but I'm concerned. The few things that were plugged into those sockets worked fine. I've switched off the breaker to that circuit so people don't use those until I've remedied the wiring. I've identified 3 outlets (all on the same circuit) where the live and neutral wires are reversed. The house I recently acquired had some wiring done in the basement by the previous owner.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |