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In both those instances the white wire should be identified as being hot, usually with black tape inside junction boxes. The neutral wire is identified by gray or white insulated wire, perhaps using stripes or markings. With lamp cord wire the ribbed wire is the neutral, and the smooth wire is the hot. NEC 2008 400.22(f) allows surface marking ...
As previously with round lamps, the US permitted only two standardized sizes of rectangular sealed-beam lamp: A system of two 200 by 142 mm (7.9 by 5.6 in) high/low beam units corresponding to the existing 7-inch round format, or a system of four 165 by 100 mm (6.5 by 3.9 in) units, two high/low and two high-beam. corresponding to the existing ...
The first rubber-insulated cables for US building wiring were introduced in 1922 with US patent 1458803, Burley, Harry & Rooney, Henry, "Insulated electric wire", issued 1923-06-12, assigned to Boston Insulated Wire and Cable . These were two or more solid copper electrical wires with rubber insulation, plus woven cotton cloth over each ...
At least two separate faults would be required to allow this relay to close inadvertently. Double switching , double cutting , or double breaking is the practice of using a multipole switch to close or open both the positive and negative sides of a DC electrical circuit , or both the hot and neutral sides of an AC circuit.
Between 1940 and 1956, all U.S. cars had to have two 7-inch (178 mm) round headlamps with dual filaments, so each lamp provided both a high and a low beam light distribution. In 1957, a system of four sealed-beam headlamps—two per side, of 5 + 3 / 4 inches (146 mm) diameter, was allowed in some U.S. states. The following year in 1958, all ...
Some telephone technicians used mnemonic phrases, such as red-right-ring-rear, or ring-right-red-rough, to remember that the red wire connects to the right-side post in the wall jack and to the ring on the plug and to the rear lug on main distribution frames. Sometimes rough or ridge was added for jumper wires with a tactile code. [citation needed]
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The positive wire is made of hard iron, while the negative wire consists of softer copper-nickel. [11] Due to its iron content, the J-type is slightly heavier and the positive wire is magnetic. [12] It is highly vulnerable to corrosion in reducing atmospheres, which can lead to significant degradation of the thermocouple's performance. [13]