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NEMA Terminal Blocks
Medium Duty - Phenolic
273
Thomas & Betts Electronics/OEM Division Tel: 901-252-5000 Fax: 901-252-1312
Dimensions shown are for reference only. Dimensions are in inches.
500 SERIES
TECHNICAL DATA
Voltage Rating: Blocks meet 300 volt creepage
and clearance requirements of NEMA, UL, and
CSA for general industrial control equipment and
panel boards. Withstand voltages greatly in
excess of IEEE switchgear standards for 750
volts. Quick connect Blocks retain 300V rating
with insulated female quick connects.
Housing:
MATERIAL: Phenolic; Filled, flame retardant
MAXIMUM SERVICE TEMP.: 150C (302F)
BREAKDOWN VOLTAGE AC, 60HZ
Contact to Contact: 6,600V (3,800V w/ Quick
Connect)
Contact to Ground: 9600V
DIELECTRIC STRENGTH: 300 Volts/mil thickness per
ASTM D149 (25C-RH40% at Sea Level)
UL HIGH VOLTAGE ARC TRACKING TEST
(INCHES/MIN.): .49-.58
WATER ABSORPTION (24 HRS. % WT. GAIN): 0.45%
per ASTM D570
FLAMMABILITY: UL94V-1
CHEMICAL RESISTANCE: Resistant to acids, alka-
lines, and aliphatic hydrocarbons and ketones,
per ASTM D543.
RADIATION RESISTANCE (ERGS G-1 (C)): 2.7 x 108
COLOR: Black
Standard Contacts
Electrical grade copper or copper alloy conduc-
tor. Steel Screws. Tube and screws are plated to
resist corrosion in most industrial applications.
Environmental Contacts
(for highly corrosive atmospheres)
TUBULAR SCREW: Electrical grade copper tube
with nickel plating. Nickel plated brass screws.
STRAP SCREW: Nickel plated brass straps and
screws. Nickel plating exceeds specification QQ-
N-290 Class I, Type VII. Maximum Width of Lugs
IS
5/16"
LR25557
E63810
Group Circuits with Interlocking Fanning Strips