What are the Legal Implications of Doing This? > 자유게시판

Locking connectors are designed so that different voltages and current ratings can not be accidentally intermated. If the neutral conductor were to break, disconnect, or develop high resistance, the appliance frame could become energized to dangerous voltages. NEMA 10s are classified as 125/250 V non-grounding (hot-hot-neutral), and were designed to be used in a manner that indirectly grounds the appliance frame to the neutral, which was common before the requirement of a separate safety ground was incorporated in the National Electrical Code. As commonly used, 10-30 and 10-50 plugs required the frame of the appliance to be indirectly grounded via a strap connecting to the neutral blade. The 14-50 has a rating of 50 A, and a straight neutral blade sized so that it does not mate with 14-30 connectors. The 14-30 has a rating of 30 A, and an L-shaped neutral blade. Miniature fuses may have an interrupting rating only 10 times their rated current.

However, to ensure that this protection has a rating matched to the appliance flexible cord fitted to the plug, a fuse rated between 1A and 13A is incorporated into each plug. Additional protection such as NM cable inside raceway is needed if the installation method is subjected to physical damage as determined by the authority having jurisdiction. This is resolved in most cases by the connector having a robust integral strain relief. The NEMA TT-30 (TT stands for Travel Trailer) connector is a 120 V 30 A recreational vehicle standard (hot-neutral-ground), also known as RV 30. The TT-30R receptacle is commonly available in nearly all RV parks in the United States and Canada, and all but the largest RVs manufactured since the 1970s use this plug to connect to power feeds. RVs in the US are equipped for 120 V 30 A or 240 V 50 A service, and use a cord to connect to a receptacle at the campsite, usually on a power pedestal with one or more receptacles providing 120 V 30 A (TT30R), 240 V 50 A (14-50R), or 120 V 15/20 A (5-20R) service.

They are also found on some RVs for connecting to shore power. NEMA 14-50 devices are frequently found in RV parks, since they are used for "shore power" connections of larger recreational vehicles. These sockets and plugs are four prong (see receptacle chart above) grounding devices (hot-hot-neutral-ground) available in ratings from 15 to 60 A. The voltage rating is 250 V. Of the straight-blade NEMA 14 devices, only 14-50 and 14-30 are in common use and either may be used for home charging of electric vehicles. NEMA 22 series devices are specified for three-pole plus neutral, five-wire grounding devices for 3-phase 277/480Y supplies. NEMA 13 series devices are three wire, three-pole, non-grounding devices for 3-phase, 600-volt equipment. According to NEMA, NEMA 23 straight-blade devices are "reserved for future configurations", so no designs for this series exist and no devices have been manufactured. According to NEMA, NEMA 21 straight-blade devices are "reserved for future configurations", so no designs for this series exist and no devices have been manufactured.

NEMA L1 series devices are single-pole plus neutral, two-wire, non-grounding devices for 125 volts single phase. There are however NEMA L21 series locking devices for 20- and 30-ampere devices specified and available for these applications. NEMA 21 series devices are specified for three-pole plus neutral, what is electric cable five-wire grounding devices for 3-phase 120/208Y supplies. Relying on the neutral conductor was a legal grounding method for electric ranges and clothes dryers, under the National Electrical Code from the 1947 to the 1993 editions (banned in 1996 edition). In February, 1979, the British Columbia Telephone Company (BC Tel) announced its plan to purchase AE's holdings, along with GTE Lenkurt Electric (Canada) Ltd. The 1911 General Electric Company (GEC) Catalogue included several earthed sockets intended for industrial use. Some local authorities continued to use them in new installations until the late 1950s. Many D&S sockets were still in use until the early 1980s, although the difficulty in obtaining plugs for them after around 1970 often forced their users to replace them with BS 1363 sockets. Scholes to propose their system as a possible solution for the new standard competing with the Dorman & Smith round pin solution, but it was not selected and the completely new BS 1363 design prevailed.