Wire Insulations

Bridgeport Insulated Wire stocks a wide variety of products. Included in the wide list of products manufactured by Bridgeport are round wire sizes #28 through #44 ASW enameled with many of the INSULATIONS listed in NEMSA MW-1000 wire specifications. Other products include Litzendraht, Gripeze, Bifilar, and other numbers of Parallel Bonded wire, server all combinations of base coat and bondable topcoats, triple and quadruple INSULATIONS thicknesses; bare, plated, and tinned copper conductors, single end, stranded, and bobbin wound multiple end; enameled resistance wire, and stranded resistance wire; stranded enameled copper wire as large as #12 AWG. 

All of our wires can be further insulated with single and double wraps of textile fibers including Glass, Daglas, Nomex, Nylon Cellulose Acetate, and Kevlar. 

FORMVAR (Class 105) (NEMA MW 15) (JW-1177/4)

FORMVAR is a polyvinyl formal resin enamel successfully used as a general purpose insulation for many years. Uses include the manufacture of oil filled transformers and electrical motors. It is an extremely tough and abrasion resistant insulation capable of withstanding severe wind ability and forming requirements. It is compatible with most varnished and encapsulants

TERASOD (ALSO ISOWELD) (Class 180) (MW-77C) (JW-1177/39)

The base resin in this wire enamel is a modified polyesterimide. It has excellent physical and electrical properties and can be soldered without prior removal of the insulation at temperatures of 850 degree Fahrenheit and higher. This insulation is available with nylon topcoat (MW-78C) (JW-1177/40) which enhances its wind ability and increases its heat shoccapabilities. It is also available with various types of bondable topcoats.

OMEGA (Class 200) (MW-74C)(JW-1177/43)

This insulation is another superior high temperature enamel based on polyester-aside-imide resins. It can be freely substituted for dual coated class 200 magnet wire in the finer sizes.

SY BONDEZE (Class 105)(MW-29C)(JW-1177/30)

This insulation is similar to POLYBOND with the exception that a layer of polyamide (nylon) is superimposed over the underlying polyurethane before the application of the butyral topcoat. This provides for higher cut-thru values than obtainable with Polybond, upgrading it to Class 130. 

POLYURETHANE ENAMEL (Class 155) (NEMA MW 79C) (JW-1144/41)P

Polyurethane resin modified with other resins comprise the enamel coating on this type of magnet wire. This film is an all purpose enamel that can be wound easily and rapidly into many types of coils. It’s unique property is its ability to be soldered without prior removal of the enamel. It is an excellent enamel for the manufacture of Litz wire because of ease of soldering, very high moisture resistance, and low dielectric losses at high frequencies.

ISONEL (Class 155)(MW-5C)(JW-1177/10)

This insulation is manufactured from a modified polyester based on terephtalic acid. It can be substituted freely as replacement for lower class insulations in many applications with a substantial increase in the temperature rating of the component. The solvent resistance of ISONEL is very good and practically all types of impregnating varnishes may be used with it.

ISOMID with AI TOPCOAT (Class 200) (MW-35C)(JW-1177/14

This insulation consists of ISOMID enameled wire with a polyamide-imide topcoat. It has superior burnout, heat shock, and cut-thru resistance. It also has excellent wind ability properties permitting its use in practically all applications subjected to continuous high temperatures and sudden overloads.


This insulation consists of Polyuretane Enamel with an additional overlying film which imparts a high friction surface to the wire. It is used as a substitute for the textile insulated wire in the manufacture of universal wound coils or other types of self supporting coils forms. Gripeze is solderable without stripping to the same degree as Polyurethane. This insulation is made in two grades: Gripeze #1 which has the same dimensions as Heavy PolyuretaneGripeze #2 which has the dimensions of Triple Polyuretane.

POLY-NYLON (Class 155) (MW-80C) (JW-1177/42)

This construction consists of a nylon enamel film over a polyurethane enamel base coat. The addition of the nylon improves cut-through temperature, wind ability, resistance to abrasion, and resistance to chemicals and solvents without any significant change in soldering properties. Because of these improved properties, this insulation is the preferred type in wire sizes 30 AWG and larger where a soldier able film is required.

ISOMID (Class 180)(MW-30C)(JW-1177/12)

This insulation is a superior high temperature enamel prepared from a polyester-polyimide polymer. It can be freely substituted fro dual coated high temperature polyester type films, and has improved heat shock, cut-through, thermal flexibility, and Freon resistance at higher temperatures.

POLYMIDE (ML) ENAMEL (Class 220)(MW-16C)(JW1177/15)

This insulation has the best high temperature properties of all wire enamels developed to date. Its burnout, heat shock, and cut-thru or thermoplastic flow resistance far exceeds that of all tether enamels.

POLYBOND (Polyurethane with a Thermaplastic Cement Overcoat) (Class 105)(MW-3C)(JW-1177/30)

This insulation consists of Polyurethane enameled wire and an additional layer of thermoplastic cement. The thickness classifications are identified as Ploybond #1, which is Single Polyurethane with sufficient overcoat to increase the diameter of the wire to that of Heavy Polyurethane, POLYBOND #2, which is Heavy Polyurethane and a layer of overcoat cement with dimensions of Triple Polyurethane. The application of heat or a suitable solvent, or both, cements all of the turns together, forming a solid bodied mass. The bondable topcoat is based on polyvinyl butyral resin.

BONDABLE TOPCOATS available from Bridgeport that can be applied to all Bridgeport Insulated Wire base coats.

Polyvinyl Butryal   125*C  100-120*C  Yes 
Polyester  150*C  150-160*C  Yes 
Aromatic Polyamide  180*C  190-220*C  No 


  • Cotton Insulated Wire (Class 90 and 105)(MW-11C)(JW-1177/46) 
  • Nylon Fiber Insulated Wire (Class 90 and 105) (MW-22C)(JW-1177/47) 
  • Cellulose Acetate Rayon Fiber Insulated Wire (Celanese)(Class 90 and 105)  
  • Nomex Fiber Insulated Wire (Class 200) 
  • Kevlar Fiber Insulated Wire (Class 220) 
  • Glass Fiber Varnish Bonded Wire (Class 180)(MW-51C)(JW-1177/33)

Next Steps

Contacus today for consultation on your next wire construction.