Lighting branch circuit
The electrical applications of different voltages
(i) The voltages does not exceeds of 120 volt is used as the followings:
- Luminaries (lighting fixtures).- Cord and plug connected loads 1440 VA.
-The voltage of 120 volt between conductors is used to supply the followings:
-The terminals of lamp-holders which rated by this limit of voltage the auxiliary equipments of electric discharge lamps such as ballasts and starting devices.
-Cord and plug connected or permanently connected utilization equipment.
(ii) The voltage of 277 volt to ground used to supplies the following:
-Electric discharge luminaries.-The incandescent luminaries which supplied be voltage of 120 volt output from Step-down autotransformer.
-Lamp-holders which rated by this value of voltage.
-Auxiliary equipments of electric discharge lamps.
-Cord and plug connected or permanently connected of utilization equipment. The voltage of 600 volt between conductors which used to supply the electric discharge lamps where the height of must not less than 6.7 meter for high ways roads and bridges and less than 5.5 meter for tunnels.
Street-tunnel lighting
Continuous and non-continuous loads
The rate of over current protective device must be not less than the rate of non-continuous loads plus 125% of continuous loads.For example:
If the continuous load is equal to 16 ampere we can select the over current– protective device according to 125%x16=20 ampere.
And the branch circuit rating can be indicated as 20 ampere.
Continuous load branch circuit
The ground fault circuit interrupter protection for personnel
When fault circuit contact with ground the high current pass through the circuit and this value of current must be reduced by any protection methods.Storage or equipment
For attics, under floor spaces, utility rooms, and basements at least one lighting outlet containing or controlled by a wall switch shall be installed where these spaces are used for storage or contain equipment requiring servicing. At least one point of control shall be at the usual point of entry to these spaces.The lighting outlet shall be provided at or near the equipment requiring servicing.Other than dwelling units
For attics and under floor spaces containing equipment requiring servicing, such as heating, air-conditioning, and refrigeration equipment, at least one lighting outlet containing a switch or controlled by a wall switch shall be installed in such spaces at least one point of controlled shall be at the usual point of entry to these spaces the lighting outlet shall be provided at or near the equipment requirement servicing.Lighting outlets required
-dwelling units:
In dwelling units, lighting outlets shall be installed in accordance with:-habitable rooms:
At least one wall switch controlled lighting outlet shall be installed in every habitable room and bathroom.-additional locations:
Additional lighting outlets shall be installed in accordance with :(1) At least one wall switch controlled lighting outlet shall be installed in hallways, stairways, attached garages, and detached garages with electric power.
(2) For dwelling unit ,attached garages ,and detached garages with electric power ,at least one wall switch controlled lighting outlet shall le installed to provide illumination on the exterior side of outdoor entrances or exits with grade level access ,a vehicle door in a garage shall not be considered as an outdoor entrance or exit.
(3) Where one or more lighting outlets are installed for interior stairways , there shall be a wall switch at each floor level , and landing level that includes an entryway , to control the lighting outlets where the stairway between floor levels has six risers or more.
15-and 20- ampere branch-circuit
A 15-and 20- ampere branch-circuit shall be permitted to supply lighting units or other utilization equipment or a combination of both, and shall comply with:-cord and plug connected equipment not fastened in place:
The rating of any one cord and plug connected utilization equipment not fastened in place shall not exceed 80 percent of the branch-circuit ampere rating.
General load branch circuit
30-ampere branch circuits
A 30-ampere branch shall be permitted to supply fixed lighting unites with heavy-duty lamp-holders in other than a dwelling unit(s) or utilization equipment on any occupancy.A rating of any one cord-and plug-connected utilization equipment shall not exceed 80 percent of the branch-circuit ampere rating.
Required outlets
-cord pendants:
A cord connector that is supplied by a permanently connected cord pendant shall be considered a receptacle outlet.-cord connections:
A receptacle outlet shall be installed wherever flexible cords with attachment plugs are used. Where flexible cords are permitted to be permanently connected, receptacles shall be permitted to be omitted for such cords.-Appliance outlets:
Appliance receptacle outlets installed in a dwelling unit for specific appliance, such as laundry equipment, shall be installed within 1.8 m of the intended location of the appliance.Dwelling unit receptacle outlets:
This section provides requirements for 125 volt, 15 and 20 ampere receptacle outlets, receptacle outlets required by this section shall be in addition to any receptacle that is part of a luminaries (lighting fixture) or appliance, located within cabinets or cupboards.40 and 50 Ampere branch circuit:
A 40-50 ampere branch circuit shall be permitted to supply cooking appliances that are fastened in place in any occupancy. in other than dwelling unites, such circuits shall be permitted to supply fixed lighting unites with heavy-duty lamp holders, infrared heating units, or other utilization equipment.A range, oven, or cooking unit to be connected to a 50-ampere branch circuit if the following four conditions are met:
· The taps are not longer than necessary to service or permit access to the junction box.
· The taps to each unit are properly spliced.
· The junction box is adjacent to each unit.
· The taps are of sufficient size for the load to be served.
· The taps to each unit are properly spliced.
· The junction box is adjacent to each unit.
· The taps are of sufficient size for the load to be served.
Tap conductors permitted
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