Figure 5-6. - Meter socket and wiring.
Figure 5-5. - Service mast service entrance.
A weather head, also called a service head, as shown in figure 5-5, is used with a raceway to provide an exit for the conductors from the raceway. The weather head is designed to prevent the entrance of rain into the raceway. The conductor holes in the service head are designed to reduce abrasion to the insulation. Power delivered to the building may need to be measured to determine how much power is used. When this measurement is necessary, a watt-hour meter socket (fig. 5-6) is installed in the service entrance circuit so that a wattmeter may be included to record power consumption. Article 230 of the NEC© covers the service conductors and equipment for control and protection of services and their installation requirements.
The service entrance must provide a means of disconnecting the service entrance conductors from the interior building circuits. The service disconnecting means will be installed at a readily accessible location either outside of a building or structure, or inside nearest the point of entrance of the service conductors. A service disconnect, or main switch, can be used to turn off all interior power in case of a fire or other emergency conditions. A disconnect switch is also useful when work is to be performed on the panelboard or work is done on two or more circuits at the same time. Overcurrent protective devices are required for the service conductors in conjunction with the service disconnects.
Several types of service entrance disconnects are permitted. One of these is in the form of a knife-blade switch with one, two, or three blades, as needed, to openContinue Reading