SPD Compatibility by Consumer Unit Brand

When replacing a Surge Protection Device (SPD), the brand and range of the existing consumer unit or distribution board are important considerations.

SPDs are not universal. Even when two devices have similar electrical ratings or fit onto the same DIN rail, this does not automatically make them suitable replacements for one another.

Do I Need the Same Brand SPD as My Consumer Unit?

The manufacturer's specified SPD arrangement should be the first place to look.

Consumer unit manufacturers commonly supply SPDs specifically intended for use with particular ranges of their equipment.

Common UK brands include:

• Wylex
• Hager
• Crabtree
• Schneider Electric
• FuseBox
• Lewden
• Contactum
• Eaton

Using an SPD associated with the correct manufacturer and range can make it considerably easier to establish the intended installation arrangement and compatibility.

Wylex SPDs

Wylex produces SPDs for use with its consumer unit and distribution equipment ranges.

When replacing a Wylex SPD, check the full part number printed on the existing device or cartridge.

Do not assume that every Wylex SPD is interchangeable. Different generations and ranges may use different devices, cartridges and connection arrangements.

If only the cartridge has failed, check whether an exact replacement cartridge is available before replacing the complete assembly.

Hager SPDs

Hager produces a wide range of surge protection equipment for domestic and commercial installations.

When identifying a Hager replacement, check:

• SPD part number
• Cartridge part number
• Type 1 or Type 2 classification
• Electrical ratings
• Number of poles
• Consumer unit or distribution board range

Hager has produced numerous SPD models, so matching the manufacturer alone is not enough to confirm compatibility.

Crabtree SPDs

Crabtree SPDs may be encountered in both domestic and commercial distribution equipment.

As with other manufacturers, the exact product range and part number should be established before selecting a replacement.

This can be particularly important with older or discontinued Crabtree equipment where the original component may no longer be part of the manufacturer's current range.

Schneider Electric SPDs

Schneider Electric produces SPDs across a number of electrical distribution product ranges.

When replacing a Schneider Electric SPD, identify the exact device rather than selecting another Schneider SPD based solely on its appearance.

Check the model number, SPD type, ratings, configuration and the manufacturer's information for the distribution equipment in which it is installed.

FuseBox SPDs

FuseBox consumer units commonly incorporate surge protection within the board.

When identifying a replacement FuseBox SPD or cartridge, check the exact product reference and specifications of the existing device.

Different versions or generations of equipment should not automatically be assumed to use identical surge protection components.

Lewden SPDs

Lewden supplies SPDs for use with its consumer units and distribution equipment.

Check the existing SPD's model number and electrical specifications before purchasing a replacement.

Where a removable cartridge is fitted, determine whether the cartridge itself has a separate replacement part number.

Can I Fit Another Brand's SPD?

An SPD from another manufacturer should not automatically be considered compatible simply because:

• It fits on a DIN rail
• It physically fits inside the enclosure
• It is also labelled Type 2
• It has a similar voltage rating
• Its terminals appear to be in similar positions

The manufacturer's instructions, electrical characteristics, connection arrangement, required protective devices and suitability for the particular assembly all need to be considered.

Replacing an SPD in an Older Consumer Unit

Finding replacements can become more difficult when the consumer unit or distribution board is from an older or discontinued range.

If the original SPD is no longer manufactured, start by recording:

• Consumer unit manufacturer
• Consumer unit or distribution board range
• Existing SPD part number
• Cartridge part number
• SPD type
• Electrical ratings
• Pole configuration
• Photographs of the existing installation

The manufacturer may have introduced a successor product, but a newer model should not be assumed to be a direct replacement without checking the relevant technical information.

Older original components may also still be available as surplus or discontinued stock.

The Most Important Rule When Replacing an SPD

Match by specification and confirmed compatibility – not appearance alone.

Two SPDs can look almost identical while being designed for different applications.

Where the exact original model is still available, searching by its full part number is generally the best starting point.

Where it is discontinued, establish whether the manufacturer specifies a suitable successor or replacement.

Finding Discontinued SPDs

ReCircuit Resale stocks a range of new, surplus and discontinued SPDs, cartridges and electrical distribution components from major manufacturers.

This can be particularly useful where an existing consumer unit contains an SPD that is no longer readily available through normal electrical wholesalers.

If you're unsure what replacement you need, provide:

• A clear photograph of the SPD
• A photograph showing the complete consumer unit or distribution board
• The SPD part number
• The consumer unit manufacturer and range

These details can make identifying the correct component considerably easier.

SPD Guides – Summary

This guide series has covered:

1. What Is an SPD and What Does It Do?
2. SPD Types Explained – Type 1, Type 2 & Type 3
3. How to Identify the Correct Replacement SPD
4. When Does an SPD Need Replacing?
5. Can You Replace Just the SPD Cartridge?
6. SPD Compatibility by Consumer Unit Brand

For replacement SPDs, cartridges and discontinued electrical components, browse the available stock from ReCircuit Resale or contact us with the part number you're trying to find.