Page 40 - IEC Insights Mar-April2020

FEATURE

Figure 3 Figure 4 Figure 5

The brokenhearted homeowner opens Even with this being the case, there service conductors supported on and
the door and collects the note. The are still millions of overhead service cabled together with a grounded bare
note informs the homeowner that the installations throughout the country. messenger where the voltage does
customer’s electrical service equipment Let’s review figures 3, 4, 5, and 6 not exceed 150 volts to ground.”
is damaged and will need the attention concerning clearance requirements for
of a licensed electrical contractor before various overhead service conductors. Figure 4 shows another scenario, the
service can be restored. A call is placed to 3.7 m (12 ft) clearance requirement. This
an area electrical contractor for assistance. Article 230, Services, of the 2017 NEC requirement is for installations “over
The receptionist answering the phone speaks to the requirements for electrical residential property and driveways, and
takes the homeowners information and services. This article contains a lot of those commercial areas not subject to
proceeds to tell him that the electrical information about electrical service truck traffic where the voltage does
contractor and crew will be there in 3 installations, but I want to concentrate not exceed 300 volts to ground.”
to 5 days. Furious, the homeowner calls on Section 230.24(B) for clearances.
the utility and demands satisfaction. The opening text at 230.24, Clearances, Figure 5 details the requirements
A utility company customer service states that “overhead service conductors for the 4.5 m (15 ft). This application
representative visits the site and explains shall not be readily accessible and shall is for “those areas listed in the 3.7
to the customer the difference between comply with 230.24(A) through (E) for m (12 ft) classification where the
customer-owned equipment and utility- services not over 1000 volts, nominal.” voltage exceeds 300 volts to ground”
owned equipment. This is typically the first (see figure 4 and figure 5).
time the homeowner truly understands Moving on to Section 230.24(B),
the meaning of the term “service point.” Vertical Clearance for Overhead The last clearance to discuss is found in
Service Conductors. The text states figure 6. This is the 5.5 m (18 ft) clearance
that overhead service conductors not “over public streets, alleys, roads, parking
The NEC and Electrical in excess of 600 volts, nominal, shall areas subject to truck traffic, driveways
Service Requirements have specific minimal clearances from on other than residential property,
final grade. There are four conditions and other land such as cultivated,
Overhead electrical services are becoming of clearance height requirements grazing, forest, and orchard.” Some
less and less preferred as a way to provide discussed in Part B of 230.24. might question as to the applicable
electricity to new homes. Many municipal nature of this requirement to dwelling
design standards and utility regulations In figure 3, we can see the 3.0 m (10 units. There are several installations
are requiring the electrical service ft) clearance requirement. This is for when an overhead service conductor
conductors to be installed underground. electrical service entrance conductors passes over an alley or street to serve
This can be aesthetically pleasing but to buildings above areas or sidewalks a dwelling unit. Public service vehicles
also helps protect these conductors from accessible only to pedestrians. This such as sanitation trucks can sometimes
excessive wind, winter icing events, and distance is measured from final grade or come in contact with these conductors
accidental contact by vehicular traffic. other accessible surfaces “for overhead when driving around the neighborhood

38 Insights Magazine | March/April 2020 | www.ieci.org