INFORMATION & REQUIREMENTS ELECTRIC SERVICE - NStar

ARTICLE 715
86
3. Three phase, 3 wire delta, 240 and 480 volt service:
A 5 terminal meter socket with manual bypass is
required. (See Sketch 19)
4. Three phase, 4 wire wye, 120/208 and 277/480 volt
service: A 7 terminal meter socket with manual bypass
is required. (See Sketch 20)
C. 400 Amperes or Less (320 Amperes Continuous
Load Capacity)
In general, self-contained socket metering (class 320) is
standard practice on single phase and three phase
installations where the service capacity is greater than
200 amperes and less than or equal to 400 amperes and the
voltage is not greater than 480 volts.
All class 320 meter installations shall be pre-approved by
the local inspection authority prior to starting work.
All approved class 320 meter sockets must be listed for use
by a recognized testing agency and have a single lever type
manually operated bypass, locking jaws, and safety shield.
All 480 volt, 3 wire and 4 wire services shall be equipped
with a disconnect switch ahead of each meter socket and
shall be within sight of the meter socket (cold sequence). If
the disconnect switch is not visible at the meter location
then it must be a lockable device.
The following is a list of socket meter requirements for
class 320 meter sockets:
1. Single phase, 3 wire, 120/240 or 120/208 volts:
A 5 terminal (in the 6 o’clock position) meter socket
with manual bypass is required. (See Sketch 21)
2. Three phase, 4 wire wye, 120/208 or 277/480 volts:
A 7 terminal meter socket with manual bypass is
required. (See Sketch 22)
ARTICLE 716-720
D. Sockets for 200 Amperes or Less Residential or
Commercial Underground Services
All 200 amperes or less 120/240 or 120/208 voltage
residential or commercial underground services shall be
ringless type with lugs on the left side of the meter socket
and bus bar connections to the line side of the meter jaws:
Residential Milbank CAT#U1980-0 or equivalent cooper
B-line CAT#EN20L44GRST or equivalent Siemans/Landis
& Gyr CAT#SUAS877-PG or equivalent.
Commercial-MILBANK CAT #U3924-XL or equivalent.
Any conduit attaching to this meter socket should have
expansion joints.
716. Cover Plates
In those instances where the meter cannot be immediately
installed upon completion of the wiring in the meter socket,
the customer is responsible to have a rigid plastic transparent
cover with blades installed in the meter socket. This cover
shall prevent accidental contact with any energized parts of the
socket as well as providing physical protection until the meter
can be installed. Under no circumstances shall cardboard be
substituted for the above described cover.
INSTRUMENT TRANSFORMER INSTALLATION
720. Instrument Transformers and Enclosures
It is the responsibility of the customer to contact the NSTAR
New Customer Connect Tech Center or the NSTAR web site
(www.nstar.com) for the proper dimensions and mounting
provisions for each set of metering current transformers.
The customer will furnish and install:
A. Current transformer cabinet with the following:
87