Is PVC allowed for service entrance conductors?

Yes. NEC 230.43 lists rigid polyvinyl chloride conduit, Type PVC, among the permitted wiring methods for service entrance conductors.

Does the exposed PVC riser have to be Schedule 80?

Where subject to physical damage, yes. NEC 352.12(C) prohibits PVC subject to physical damage unless identified for that use, and 300.5(D) lists Schedule 80 PVC as acceptable protection from the required cover depth to 8 feet above grade.

Can underground service entrance PVC enter the bottom of a main disconnect?

Q: Do you have to seal an underground service raceway?

Yes. NEC 300.5(H) requires the end of an underground raceway within the building to be sealed with an identified compound to prevent moisture and gases from entering, and 230.53 requires service raceways to be raintight and arranged to drain.

Yes. Bringing an underground service raceway up through the bottom of a meter main or a service disconnect is the standard way it is done, and PVC is a permitted service raceway. There are four details that make or break the inspection, and none of them are about the direction of entry.

PVC is a listed service raceway

Section 230.43 of the 2023 NEC lists the wiring methods permitted for service entrance conductors, and rigid polyvinyl chloride conduit, Type PVC, is on that list along with rigid metal conduit, intermediate metal conduit, electrical metallic tubing, service entrance cable, and others. Article 352 governs its installation. Section 352.10 covers permitted uses, including direct burial and concealed installations.

Physical damage and the exposed riser

Section 352.12(C) prohibits PVC where subject to physical damage unless identified for that use. Schedule 80 PVC is identified for areas subject to physical damage, which is why the exposed riser from grade up to the enclosure is normally Schedule 80 even when the buried portion is Schedule 40. Section 300.5(D)(4) requires direct buried conductors and cables emerging from grade to be protected by an enclosure or raceway extending from the minimum cover distance required by 300.5(A) to a point at least 2.5 m (8 ft) above finished grade. Section 300.5(D)(1) lists the acceptable protection methods, which include rigid metal conduit, intermediate metal conduit, Schedule 80 PVC, RTRC-XW, and other approved means.

Burial depth and the trench

Table 300.5(A) sets minimum cover. For service raceways in residential work, Schedule 40 PVC generally needs 18 in. of cover in a normal location under column 4, and 24 in. under a driveway or parking area, with reduced depths permitted under a building or under a concrete slab as the table describes. Section 230.6 also matters, because conductors are considered outside a building when installed under not less than 2 in. of concrete beneath a building, in a raceway encased in not less than 2 in. of concrete or brick, or in a raceway under not less than 18 in. of earth beneath a building. That is how service conductors legally travel under a slab to reach the disconnect.

Drainage, sealing, and the bushing

Section 230.53 requires service raceways to be raintight and arranged to drain. Section 300.5(H) requires the underground raceway end within the building to be sealed with an identified compound to prevent moisture and gases from entering, and requires a bushing or terminal fitting where conductors emerge from a raceway. A bottom entry into a wall mounted meter main is the easiest place to satisfy the drain requirement, and duct seal in the raceway end after the pull satisfies the sealing requirement. Section 300.4(G) requires an insulating bushing where 4 AWG and larger conductors enter the enclosure, and every service conductor of consequence is larger than 4 AWG.

Disconnect location

Section 230.70(A)(1) requires the service disconnecting means to be installed at a readily accessible location either outside the building or inside nearest the point of entrance of the service conductors. Section 230.70(A)(2) prohibits installing it in bathrooms. For one and two family dwellings, Section 230.85 requires an emergency disconnect at a readily accessible outdoor location with the specified marking.

Field takeaway

Bottom entry with PVC is fine. Use Schedule 80 on the exposed riser, hit the Table 300.5(A) cover depth, seal the raceway end per 300.5(H), install a bushing on the conductors, and keep the disconnect nearest the point of entrance.