Filing Down Polarized Plug Could Cause Shock Hazard
Question: Can I file down the wide tip on a polarized plug without bad effects?
Answer: No. Inserting a polarized plug incorrectly, which is possible if you file down the wide prong, could cause a shock hazard by making the appliance cabinet live even when the switch is turned off. The slots in a polarized receptacle are different sizes to prevent this very thing. The wide slot is connected to the neutral wire and the narrow one to the hot wire. The polarized plug ensures that the inlet side of the appliance switch is connected to the hot lead. This keeps components beyond the switch inside the appliance from being electrically hot when the switch is turned off.
If you have nonpolarized outlets and need to plug in a polarized appliance such as a television set, don’t ever file down the wide plug prong. Instead, you should replace the receptacle with a polarized outlet and make sure it has been wired correctly with the neutral wire going to the terminal for the wide prong and the black hot lead going to the one for the narrow prong.
If you decide to do the job yourself, you can get the polarized outlet at any hardware store or home center. The copper-colored screw is the one to which you attach the black wire and the silver-colored one is for the white wire.
Plugged-In Transformer Still Uses Electricity
Q: I have a question regarding rechargeable tools and small appliances around the home. Most rechargeable items plug into a charger/transformer that, in turn, is plugged into a wall outlet. If the transformer is plugged in, but the appliance is not connected to the charger cord, does the transformer still use electricity? Is there any fire hazard with these transformers?
A: The transformer does use electricity, but at a lesser amount than it would draw if the appliance was plugged into the transformer while being recharged. Providing that the transformer is used properly, and has a UL listing attached to it (or any other third-party testing agency’s label) then there is generally no fire hazard associated with the device.
Water Heaters Differ in Thermostat Settings
Q: Most hot-water tanks have a dial for water temperatures at their bottom. They read hot, warm and normal. What are the temperatures? I have heard that the minimum temperatures should be 120 F and the maximum 140 F.
A: Not all water-heater manufacturers use the same names for the thermostat settings. Nevertheless, the settings are basically hot, medium and warm. On some water heaters, there is also a vacation setting. According to manufacturers, the respective temperatures are 160 F, 140 F, 120 F and 60 F. These temperatures are not precise as there can be a difference of 10 degrees or more between the dial setting and the water’s temperature.
The thermostat for a tank-type water heater is at the lower portion of the tank.
Since hot water rises, the temperature of the water at the top of the tank (where the hot water outlet pipe is located) will be higher than the water surrounding the thermostat.
You must also consider that as the hot water flows through the distribution pipes, some heat will be lost. Consequently, the water temperature discharging from the various faucets will be lower than the water temperature at the top of the heater tank.
For the most part, a thermostat setting that produces a water temperature of 140 F will be adequate for household appliances such as clothes washers and dishwashers. However, when dishes are to be washed by hand or when bathing, a water temperature of 120 F is probably too hot for most people and needs to be tempered with a bit of cold water.
Setting the thermostat so its temperature exceeds 140 F is wasteful of energy and will shorten the life of the water heater. Water temperature in excess of 160 F is a potential hazard because of the possibility of being scalded while showering if the shower’s mixing valve is faulty.
Replace Rotting Railroad Ties, Not Entire Fence
Q: I built a retaining wall of used railroad ties. In a few areas, the rot is creating holes. Is there any way I can remedy this situation besides rebuilding the entire wall?
A: There really isn’t much you can do about repairing the rotting sections in your retaining wall. There are epoxy fillers that are used to rehabilitate rotting trim in houses but they are not intended for retaining walls. If you only have a few sections that are rotted, and if the structural bracing for the wall (tie backs and dead men) has not deteriorated, then reconstructing the entire wall should not be necessary. You can remove the extensively rotted ties and replace them.
Rotten used railroad ties are not unusual. This is because the species of wood that are used for railroad ties are difficult to impregnate with creosote. Consequently, there is quite a lot of untreated wood and moisture in the interior of the ties. When the ties dry, they check and split, exposing the interior portion to some decay.
Furthermore, creosote consists of hundreds of components, some of which are soluble in water. Over time, the creosote retained in the tie is depleted as these components leach out. Eventually, decay occurs in the ties.
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To submit a question, write to Popular Mechanics, Reader Service Bureau, 224 W. 57th St., New York, NY 10019. The most interesting questions will be answered in a future column.
