Services & DistributionQuestion 85 of 521
The general minimum vertical clearance of overhead service conductors above a roof surface (voltage not over 300 V to ground) is:
a.3 ft
b.6 ft
c.8 ft
d.10 ft
Explanation
Per 230.24(A), the general clearance above a roof is 8 ft (2.5 m), measured over the area where the conductors pass. Reduced clearances (such as 3 ft) apply only under specific listed exceptions like limited slope or attachment conditions.
Law Reference: 2023 NEC §230.24Practice all 521 questions free — no signup required.
Related questions on this topic
- A concrete-encased electrode (Ufer) must consist of at least 20 ft (6.0 m) of:
- A single made rod electrode is measured at 40 ohms resistance to earth. The code requires that it be:
- Overhead service conductors (service drop) over a residential driveway with no truck traffic must maintain a minimum vertical clearance above grade of:
- The point of attachment of overhead service conductors to a building must be at least what height above finished grade?
- A feeder supplies a single continuous load of 100 A. The minimum feeder conductor ampacity and overcurrent device rating is:
- A supply-side bonding jumper on the line side of the service, used to bond service raceways and enclosures, is generally sized based on:
Last reviewed: · editorial process
PrepPass Editorial Team · Verified against California CSLB C-10 Electrical Trade Examination · How we review