Storm Power’s Design Guide to Flexible Insulated Busbar

General Design Guide for Flexible Insulated Busbar


Custom part fabrication with Flexible Insulated Busbar will conform to fit requirements when installed, but dimensions may vary when loose. This is due to Flexible Insulated Busbar's inherent flexibility; its shape can be altered slightly during handling and shipment. This will quickly be remedied as the parts are assembled into their application.


From a design aspect, solid copper bar (especially thickness over 0.125”) has the ability to be bent and maintain angles throughout handling, shipping and installation.

Not so with Flexible Insulated Busbar. It is flexible by design.  

Flexible Insulated Busbar material is annealed laminated layers of copper that when bent slide upon each other. Annealing softens the copper allowing the layers to bend easier without impacting insulation integrity.

The outer sleeve of vinyl serves as a flexible insulator, but does not allow the bends to have a permanent set like a solid copper bar.  So bends are made prior to installing holes. (opposite of solid copper bar).


If Flexible Insulated Busbar is only cut to length and holes punched, linear dimensions such as overall length can be maintained.  For parts with bends and/or twists, it is unlikely overall length will be held to general tolerances. So, if a rigid dimension MUST be held for overall length, one might consider using solid copper bar instead.


Hole Diameters & Slots

Generally, hole diameters and slots can be held to ± 0.015".
Edge-of-hole/slot to edge-of-part minimum distance is 0.188" or 1.5 times the total laminate thickness.
Slotted holes are recommended where additional forming/manipulation is anticipated during installation.


Hole Centers - Cut Lengths

±0.060" on straight lengths. Parts with multiple bends and/or twists could require more tolerance.


Bending Radii

It is preferred that all radii be consistent on each part. That is, all are 0.50" or all are 0.75".


Bending Angles

Due to Flexible Insulated Busbar's inherent flexibility, individual layers of laminate sliding upon each other during bending, and the “memory” factor of the insulation, it is recommended angular requirements be treated as reference dimensions.



Flexible Insulated Busbar can be twisted along its length. The best results are obtained when the twists are 90 degrees or less and the material allowance for the twists is a minimum of three times the width (including insulation- 0.079" per side).


Insulation Stripping

±0.060" on straight flat lengths without bends or twists, with generally square insulation cut on all sides.
On ends near a bend or twist, insulation will move and be pulled into various shapes due to the forces placed on it. As a result, distance from the end of part may vary between top and bottom surfaces. With thicker material (more laminates) this effect is more pronounced. A tolerance of ±0.060" is achievable on either the top or bottom surface, but not both because of this effect. A minimum length of 0.50" from the end of the insulation to the start of any bend is recommended.



Finishing of ends, if required, is done by hand; this is not normally necessary with production tooling.



To avoid damage to insulation, Flexible Insulated Busbar should not be handled when it has been exposed to temperatures of 30° F or less for any length of time.