Electric Service Entrance Requirements

The NEC 2020 cycle has seen an additional change that will affect electrical service facilities in residential buildings. New section 230.67 requires that all electrical services in residential units be equipped with a surge protection device (DSP). The SPD shall be an integral part of the service device or be mounted directly next to the service device and be a Type 1 or Type 2 SPD. Many manufacturers now offer home control panels with built-in SPD to meet this new code requirement. Similar to the emergency separation requirement, this spd requirement applies to both new services and services that are modified or updated. Based on a change incorporated into the NEC 2020, emergency separation in accordance with Article 230.85 is now required. This separation is designed to give first responders the ability to turn off the power supply to the entire home before entering to resolve the emergency. The NEC requires that the disconnect connection be installed outdoors in an easily accessible location and be identified as an emergency disconnection. In the previously mentioned scenarios, where the main separation has been installed outside inside the control panel or in an installed service separation due to the distance that the service entrance lines lead into the building, it is only a matter of changing the way the service separation is marked. It must be marked as „EMERGENCY DISCONNECTION, SERVICE DISCONNECTION“ or, if applicable, as one of the other two marking options listed in section 230.85. For an installation in which the service managers leave the meter, enter the house and enter directly into the control panel, an external emergency separation for the house should now be installed. Section 230.85 requires that an emergency disconnection be installed for all new electrical services, as well as for the modification or upgrade of an electrical service.

While some of the points discussed in this blog are new to residential electrical services, there are many that remain proven. For example, the sizing of conductors and service input lines, as well as the sizing of grounding and linking conductors, remain consistent with how they have been performed in the NEC for some time. To verify these requirements, the following scenario is used to explain each domain. The grounding electrode system in electrical services creates a common connection between electrical equipment, grounding electrodes present and/or required, and the Earth so that they are in the same relative potential. This helps stabilize the voltage on the system and limits the voltage that can be imposed on the system by lightning and other potential power surges. Section 250.50 of the NEC states that all grounding electrodes listed in points 250.52(A)(1) to 250.52(A)(7) that are present in the building or structure must be joined together to form the grounding electrode system. Here are grounding electrodes, some with specific requirements, approved by the NEC for grounding: Scenario: 200 amps, 120/240 volts, 3-wire single-phase electrical service with THWN copper service input conductors installed in the ANNEX 40 PVC channel and a copper grounding electrode conductor and copper bond wires. Once the work is done to determine the size of the electrical service and the desired location for some of the service equipment such as the control panel and meter, our next conversation with the utility or utility provider (POCO) must take place.

Although many POCOs work differently, it is quite common for them to give you information, for example, whether the house is powered above or below the ground, or if you have the option to choose. They will also confirm that the desired location of the meter works for what they need. In a country house scenario, the builder and POCO have probably already discussed these points and have a plan. However, in a scenario where a single custom home is built on 10 acres of land, this conversation with the POCO becomes even more important for the process and helps avoid hiccups. For example, depending on the rights of way available to the utility, they may only be able to bring energy to a certain corner of the house. If the meter is mounted in the opposite corner of the house, the POCO may not provide power until it is installed. Having the right conversations to gather the right information long before a screwdriver is turned to install the equipment is the key to any successful project. In most residential applications, the most common grounding electrodes integrated into the grounding electrode system are the concrete sheathed electrode (UFER), rod electrodes (grounding rods), and metal water pipes, although this is becoming increasingly rare due to the increasing use of plastic pipes instead of metal for water supply. Nec Table 250.66 is used to determine the wire size we should use for our grounding electrode conductor based on the largest (hot) service input conductor unearthed. Since we have previously determined that our service input leader will be THWN 2/0 AWG size copper and the scenario also indicates that the grounding electrode conductor must be copper, we can now use Table 250.66 to determine that we will use an AWG No. 4 copper grounding electrode conductor for this electrical service. The only caveat is that the grounding electrode conductor guided to the earth rods does not need to be larger than AWG No.

6 copper. All other conductive connections of grounding electrodes, e.g. to the metal water pipe and the concrete-coated electrode, shall be sized as the AWG #4 copper required in Table 250.66. To properly size our service input ladders, we turn to Table 310.12, which discusses wire size for single-phase housing services and feeders. Use of scenario information that we have an electrical service of 200 amps and use copper conductors; We find that our service input conductors for this electrical service must be 2/0 AWG copper THWN conductors. Many electrical services in private buildings must be answered before the installation can be carried out. Some electrical services for private households are prefabricated and already have the information at your disposal. For example, in custom home scenarios, it`s common to have to gather information from the builder and/or owner in advance. The equipment installed in the house may be minimal or extravagant, but the electrical needs of both must be met accordingly. The size of the house and the loads of the device have a direct impact on the overall size of the electrical service. As another example, if you work in a residential subdivision, the builder has probably already predetermined many points that you usually need to determine for yourself before installation, such as the size of the electrical service you need to install and the location of the control panel.