Electrically Insulated Bearings reliably prevent current discharge. Electrically Insulated Bearings provides bearings with oxide ceramic insulating layers on the bearing ring. Applied with plasma technology, the insulation has a guaranteed breakdown resistance of at least 1000V AC or DC. Two variants are available:
SQ77: Insulation on the outer ring
SQ77E: Insulation on the inner ring

Product range

SQ77 (insulated outer ring)
Cylindrical roller bearings 
Design variants: NJ, NU, NUP
Dimension series: 210-230, 310-330
Cages: brass and polyamide
Radial clearance groups: C0, C3, C4
Deep groove ball bearings 
Dimension series: 6212-6226; 6312-6326
Cages: brass
Radial clearance groups: C3, C4
Other types and SQ77E (insulated inner ring) upon request

Advantages

Higher operational reliability through optimum protection against electrical corrosion
More economic than, for example, insulation on housings or shafts
Interchangeable: Same key dimensions and technical properties as conventional bearings
Coating resistant to damage if correctly handled