Cut Sheet

How to Achieve a Good Electrical Connection
THE QUALITY OF AN ELECTRICAL
CONTACT IS DETERMINED BY:
TWO WAYS TO CONNECT
IN PARALLEL:
Belleville
washer
Flat
washer
Flat
washer
Belleville
washer
1. CONTACT SURFACE CONDITIONS
The surface has to be flat but not polished. Another important point: cleaning
the surfaces before connection. They must be oxide and grease free.
2. CONTACT SURFACE(S) - OVERLAP
The overlap (H) should be not less than 5 times the thickness (e)
of the thinnest of the conductors.
3. CLAMPING TORQUE CALCULATION
With a class coated bichromated bolt (SAE Grade 5), using “Belleville
and Flat” washers tightened with a torque wrench, without lubrication.
• SAE Grade 5 hardware can be used except where otherwise
designated by the designer of the pieces installed
• Belleville and Flat washers to provide resistance to vibration
• Slotted holes are acceptable in applications where additional
forming is anticipated during installation
Bolt size 1/4”-20 5/16”-18 3/8”-16 7/16”-14 1/2”-13 9/16”-12 5/8”-11
Torque
(foot-pounds)
9 18 31 50 75 110 150
Alt - Metric
Bolt size M6 M8 M10 M12 M14 M16
Torque
(newton-meters)
13 30 60 110 174 274
Top ERIFLEX FLEXIBAR must be
stripped and bent to insure good
contact area
Install with Grade 5 or better
hardware and torque
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Grade 5 Bolt
Grade 5 Bolt
Belleville Washer
Belleville Washer
Belleville Washer
Belleville Washer
Contactor /
Circuit Breaker
Contactor /
Circuit Breaker
Grade 5 Nut
Grade 5 Nut
Flat Washer
Flat Washer
Flat Washer
Flat Washer
ERIFLEX FLEXIBAR
ERIFLEX FLEXIBAR