35 kV Busbar Insulation (MPG35)

Thick-wall pre-cut insulation sections for 35 kV busbars, verified at 105 kV power frequency withstand.

Models MPG35
Operating temp -40 to +105 °C
Voltage class 35 kV
Standards GB/T 12706, UL 94 V-0, RoHS
Contact our engineers.
35 kV Busbar Insulation (MPG35)

Product Overview

MPG35 is the highest voltage grade of the MPG busbar tubing family: a thick-wall radiation-crosslinked polyolefin product formulated for insulating copper and aluminum busbars in 35 kV distribution equipment. Its 2.0+ mm recovered walls and 105 kV power frequency withstand capability bring shrink-to-fit insulation to primary distribution switchgear that previously required large air clearances or custom-molded covers.

MPG35 is supplied as pre-cut 1 m sections sized to standard busbar widths, which are slipped over the busbar before joint assembly. Upon heating to 110-130°C, each section recovers to grip the busbar surface without adhesive, relying on mechanical shrink force to maintain permanent contact. Busbar joint protection boxes are available per customer requirements for T-joints, L-joints and cross-overs.

Performance Data

PropertyTest MethodRequirement
Limited oxygen index (LOI)—>30
Low-temperature flexibility-40°CNo cracking
Flame retardancyUL 94V-0 equivalent
Tracking resistanceIEC 605871A 4.5 kV (typical for crosslinked PO)
PropertyTest MethodTypical Value
Long-term operating temperature—105°C
Tensile strengthASTM D63811 MPa
Elongation at breakASTM D638300%
Volume resistivityIEC 932×10¹⁴ Ω·cm
Water absorptionISO 62<0.5%
Tensile after aging (158°C, 7 d)ASTM D63811 MPa
Elongation after aging (158°C, 7 d)ASTM D638310%
Dielectric strengthIEC 24323 kV/mm
Power frequency withstand—105 kV, 60 s, no flashover
Wall bias—15%
Longitudinal change (200°C, 3 min)—-5%

Internal test data. Questions on parameters? Contact our engineers.

Size Specifications

ModelBusbar Width (mm)Recovered ID (mm)Section (mm)
MPG35-XX-25/1020-30<10Φ25 × 1000
MPG35-XX-30/1230-40<12Φ30 × 1000
MPG35-XX-40/1640-50<16Φ40 × 1000
MPG35-XX-50/2050-60<20Φ50 × 1000
MPG35-XX-65/2560-70<25Φ65 × 1000
MPG35-XX-75/3080-90<30Φ75 × 1000
MPG35-XX-85/3590-100<35Φ85 × 1000
MPG35-XX-100/45120<45Φ100 × 1000
MPG35-XX-120/50140<50Φ120 × 1000
MPG35-XX-150/60180<60Φ150 × 1000
MPG35-XX-200/60240<60Φ200 × 1000

Standard color: black. Custom colors available — contact our sales team.

Applications

Switchgear Busbar Insulation

Cover main, distribution and tie busbars in 35 kV metal-clad switchgear. Pre-cut sections and joint boxes replace custom-molded boots at every busbar joint.

Generator Bus Duct

Insulate isolated phase bus and non-segregated phase bus runs in power generation facilities. The tracking-resistant formulation handles thermal cycling and vibration in rotating machine connections.

Transformer Bushing Connections

Insulate LV bushing leads and delta connections in dry-type and oil-filled transformer enclosures. The 105°C continuous rating matches Class A and Class B insulation systems.

Standards

FAQ

How much clearance can I save with MPG tubing?
At 35 kV, MPG35 reduces clearance from 320 mm to 200 mm (phase-to-ground) and 150 mm (phase-to-phase). Actual values depend on your panel design and applicable standards.
What is the difference between MPG10 and MPG35?
Both are 105°C-rated crosslinked polyolefin, but MPG35 has thicker walls (2.0+ mm recovered) and passes a 105 kV/60-second power frequency withstand test (vs. 45 kV for MPG10). MPG35 also has stricter wall bias (15% vs. 30%) for more uniform insulation. Use MPG10 for 10 kV systems and below; use MPG35 for 35 kV systems.
How do I select the correct size?
Measure the busbar width (the largest dimension perpendicular to the direction of slide-on). Select a size where the expanded ID exceeds the busbar diagonal by at least 15%, and the recovered ID is smaller than the busbar width to ensure a tight fit. For rectangular busbars, use the diagonal: √(width² + thickness²).
Do you supply busbar joint protection boxes?
Yes. Busbar joint boxes are available per customer requirements for all MPG grades. These cover T-joints, L-joints, and cross-overs where standard tubing cannot provide complete coverage. Contact us with your joint configuration drawing.
What heat source is needed for installation?
Heat guns with reflector attachments work well for individual busbars. For batch production, infrared ovens or induction heating systems provide uniform shrinkage. Target temperature is 110-130°C; avoid exceeding 150°C as this may cause surface gloss loss or wall thinning.

Still deciding? Contact our engineers.

Tell us your cable size, voltage and environment. We reply within one business day.

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