Contents Introduction Overhead Underground Meters Glossary

DIRECT-CONNECT METERS

Direct-connect meters carry full load current and connect directly across full line voltage. Direct-connect meters are also called self-contained meters.

Direct-connect, socket-type meters are installed on these services:
       ▪ Single-phase, up to 400 amps
       ▪ Three-phase, up to 200 amps, and with motors up to 60 hp for 120/208 or 120/240 volt service, and up to 125 hp for 277/480 volt service

Services larger than these are metered using instrument-rated meters with current transformers. If the voltage is over 600 volts, voltage transformers are used.

Services Metered Using Direct-Connect Meters
Services metered by direct-connect meters, are illustrated here.

For single-phase services:

120/240V 3-Wire
120/208V 3-Wire Network

For three-phase services:

       120/208V 4-Wire Wye                    277/480V 4-Wire Wye                  120/240V 4-Wire Delta