Underground electrical service entry (C) Daniel Friedman Table of Underground Electrical Service Cable Sizes & Amps

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Buried or underground electrical service entry cable ampacity & underground electrical service ampacity ratings:

How to determine the size, capacity, or ampacity of electrical service at a building.

This article explains how to estimate the electrical service size, (or "electrical power" or "service amps") at a building by visual examination of the buried service entry cables and other details that are available by simple visual inspection.

We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

UNDERGROUND Electrical SERVICE LATERALS - delivering current to a building

Electrical Services provided through underground conduit do not permit visual inspection of the service conductor prior to the electric meter and actual conductors are visible only in the service panel.

It is possible to guess at the cable run in a conduit by the diameter of the conduit itself [Table 2.] But for conductors from the utility company's drop to the meter, conduit size sets only the maximum conductor that could be contained, not necessarily the actual size.

Table 2. [Electrical Service Conductor Cable Sizes & Amps Ratings for] Service Conductors in Conduit

Rigid non-metallic
conduit or iron pipe diam.


1" in Canada

1001 1/4"
200 2"

Notes to Table:

Pipe sizes are nominal; for copper wires.

Watch out: Do not attempt to open the meter base. If you are unable to determine the wire ampacity because there is no view, or because its dimension is not one with which you are familiar, say so.

Service Entry Wiring Guides, Procedures, & More Sizing Tables


Continue reading at VISUALLY DETERMINE AMPS & VOLTS or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.


Or see ELECTRICAL INSPECTOR SAFETY PROCEDURES important basic safety procedures, clothing, and equipment for home inspectors and electrical inspectors.

Or see SE CABLE SIZES vs AMPS for more wire size guidelines

Or see SIZE of WIRE REQUIRED for ELECTRICAL RECEPTACLES for receptacle circuits and similar wiring situations

Or see these

Articles on Building Electrical Service Wiring - SEC Cabling

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UNDERGROUND SERVICE LATERALS at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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