SRBP Washers

SRBP Washers

SRBP Washers

Advanced Seals & Gaskets Ltd offer a multitude of washers converted using a wide selection of sealing and gasketing materials, sourced from a network of suppliers, some of which are needed for specialist applications.  One range on offer from our vast catalogue are various types of electrical insulating materials with one type being Synthetic Resin Bonded Paper Electrical Insulation, sometimes also called SRBP Paper, SRBP Board or Phenolic Paper Laminate.

SRBP is usually manufactured in sheet form usually at 1220mm x 1220mm and in a range of  thicknesses from 0.5mm to 20mm from which washers can be cut or pressed.   All our SRBP washers are manufactured in-house using a combination of a skilled workforce and high spec machinery in practically any size and quantity, with a plain or self-adhesive finish to one or both faces.

SRBP washers are produced using samples, dimensions or drawings provided by our customers which would detail the Outer Diameter (OD), Internal Diameter (ID) and the thickness, from a one off sample to multi-thousand batch runs, we have a machine to quickly and accurately produce perfectly formed washers in a range of sizes, these include a number of presses and CNC machines.

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Product Enquiry

For information on SRBP Washers please complete the following quick enquiry or call us on +44(0)1384 252555.






    Key Characteristics of SRBP

    • Colour: Brown
    • Sheet Size: 1220mm x 1220mm
    • Thicknesses available:  0.5mm to 20mm
    • Temperature: Up to +105°C continuous
    • Standards: BS EN60893, standard 3-4 PFCP201
    • BS EN60893, standard 3-4 PFCP203
    • BS EN 60893 Standard: 3-4-PFCP206

    Full technical data can be supplied upon request,
    or downloaded from our online portal.

    Product Specification Sheet

    What are SRBP Washers?

    Washers are a flattened ‘ring’ of material consisting of an ID (inner diameter) and OD (outer diameter), which can be placed between  two surfaces to reduce friction, prevent unsteadiness,  to create a smooth, level surface for nuts and bolts to rest on, to create a better fit for fixtures and fittings and can be used as a air/water tight seal.  Synthetic Resin Bonded Paper or SRBP  is a brown coloured composite material made of compressed layers of paper which is impregnated with a plasticized phenol-formaldehyde resin and bonded under pressure and high temperature, designed for it’s electrical insulation properties ideal for washer conversion.

    Why use SRBP Washers?

    SRBP Washers are often found used within electrical insulation applications, providing a barrier to restrict the flow of electrical current, protecting electrical conductors from coming into contact with people or tools during installation, repairs or when an electrical appliance or device is being used.

    Electrical insulation washers also prevent electrical arcing (electrical current flows through the air between two conductors, as a result of the electrical breakdown of gas that produces an ongoing electrical discharge) and are used in other electrical insulation applications.

    Although paper types of insulating material don’t usually offer the mechanical characteristics or strength of those made using fabric, they offer superior electrical insulation properties, making them better suited to medium or high voltage applications, even in applications where there is exposure to humidity and oil.  Because of the rigidity of SRBP, we can convert the sheets using the same processes used for plastics such as routing, drilling, milling and sawing, in order to produce parts such as washers.

    Grades of SRBP Electrical Insulation

    Low Voltage

    • Meets BS EN60893, standard 3-4 PFCP201
    • Temperature: Up to +100°C continuous
    • More economical grade
    • Used in Low voltage applications

    Medium Voltage 

    • Meets BS EN60893, standard 3-4 PFCP203
    • Temperature: Up to +105°C continuous
    • Better oil absorption than the high voltage grade
    • Low water absorptionUsed in Medium voltage applications

    High Voltage

    • Meets BS EN 60893 Standard: 3-4-PFCP206
    • Temperature: Up to +105°C continuous
    • Good electrical properties both in air and oil.
    • Low moisture absorption.
    • High thermal resistance
    • Used in High voltage application

    Advantages of Using SRBP Washers

    Customers using washers made from SRBP benefit from a number of advantages.  SRBP is manufactured in a wide range of thicknesses and is available in 3 grades for use with varying levels of electrical voltage.

    As well as the excellent electrical insulation properties, SRBP washers offer good mechanical strength, low moisture absorption, with the material itself   being easy to cut and form into washers of any size using a range of techniques including routing, drilling, milling and sawing,  which can be found utilised in electrical components, electrical switchgear, lighting, transformers and within many engineering applications.

    The Benefits of Using SRBP Electrical Insulation

    • Excellent electrical properties even when submerged in oil.
    • Easy to machine
    • Low moisture absorption even in humid conditions
    • Operating Temperature of 105°C continuous (+120°C intermittent)
    • High thermal resistance.
    Have a Question About SRBP Washers?

    Please contact us using the form below or by calling us on +44(0)1384 252555.