Architectural Electrical Symbols used in house (dwelling) construction
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Architectural Electrical Symbols
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Great drawings. Many folks don't know these symbols.
Thanks!Last edited by Speedy Petey; 10-09-2007, 08:48 PM.
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When you have a SERVICE ENTRANCE PANEL the neutral is always bonded to the enclosure by means of a bondingscrew (green) OR A neutral bonding jumper. - in the case of a sub panel the neutral bar is not bonded to the enclosure but there is an auxillary ground strip that is fastened to the enclosure. The theory is that objectionable current - fault current - is routed to earth ground whenever there is a short or a leakage path to ground. The purpose is to have the fault take a more direct path to ground and trip the breaker or blow a fuse eliminating a hazard. A motor winding can develop a fault path through its enamelled insulation and ground itself to its metal case but because of a high resistance may not blow a breaker through the neutral wire but enough to energize the ground path because the motor case is grounded the breaker will blow. a motor lead's path is from a hot to the motor winding which is a coil - through the coil to the neutral wire with 120 volts. a break or abrsion in the middle causes a leakage path even tho the neutral is still connected to the coil's exit path.
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Any panelbox may serve as a main panel housing a main breaker and branch circuit breakers. a sub panel is a similar panelbox minus a main breaker. Its terminations are usually just main line lugs. branch circuit breakers connect on the stabs of the panel. A double pole circuit breaker feeds this panel from the main panelbox.
The sub is just an extension of the main box to keep load conductors short(er) than running all the way back to the main.
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