How can a type 2 surge protection device protect your electrical equipment from surges

 

A voltage surge can last for only a few microseconds, yet it can damage control panels, electronic equipment and other connected loads. Lightning-induced disturbances and switching operations can create these sudden voltage rises. A surge protection device spd helps limit that voltage and reduce the stress reaching downstream equipment.

 

A Type 2 surge protection device protects electrical equipment by limiting transient voltage and diverting surge current away from downstream circuits. It is commonly installed at distribution boards to reduce the surge energy reaching connected equipment such as control panels, automation systems and electronic devices.

What is a Type 2 surge protection device?

A surge protection device type 2 is installed in low-voltage distribution systems to limit transient overvoltage. It is commonly fitted at a distribution board after the incoming protection, protecting circuits and equipment further down the installation.

 

Axis offers Type 2 SPDs for single-phase and three-phase applications.

Protection point	SPD type	Main purpose
Main incoming supply	Type 1	Handles high-energy surge exposure, including lightning-related surges
Main distribution point	Type 1+2	Combines Type 1 and Type 2 protection
Distribution board	Type 2	Limits transient overvoltage reaching downstream circuits
Close to sensitive equipment	Type 3	Provides additional protection for sensitive electronic equipment

 

How does a Type 2 SPD protect electrical equipment?

1. Limits excessive voltage

During a surge, the voltage across the circuit can rise far above its normal operating level. Sensitive components may not withstand this sudden increase.

 

A surge protection device type 2 limits the transient voltage to a lower level, reducing electrical stress on connected equipment. The remaining voltage is referred to as the protection level of the SPD.

 

This value is known as Up, or voltage protection level, and it is an important specification when matching an SPD to the withstand capability of the equipment being protected.

2. Diverts surge current

A Type 2 SPD connects in parallel with the circuit rather than directly in series with the load. When a surge occurs, the device provides a path for the surge current, helping keep the abnormal current away from sensitive equipment.

 

Axis Type 2 devices use Metal Oxide Varistors (MOVs). An MOV changes its resistance with applied voltage, allowing it to conduct during a surge and return to a high-resistance state during normal operation.

 

Check the SPD's surge-current ratings, such as In and Imax, against the expected surge exposure rather than choosing a device only because it has a higher kA rating.

3. Reduces damage from switching surges

Not every surge comes from a lightning strike. Switching operations in an electrical installation can also create transient voltage spikes.

 

This is where a surge protection device spd can help. Type 2 devices are intended for distribution-level protection and are commonly used to handle switching-related surges within the installation.

4. Protects downstream equipment

Equipment connected downstream can include PLCs, control panels, automation systems, communication equipment and other sensitive electronics. A surge reaching these devices can cause malfunction or permanent damage.

 

A surge protection device type 2 is placed upstream of these loads so that transient voltage is limited before it reaches them. The SPD connection length and installation arrangement can affect the protection available at the equipment.

5. Works as part of a complete protection system

A Type 2 SPD is one part of a wider surge protection arrangement. In installations with higher exposure, Type 1 or Type 1+2 protection may be used at the incoming panel, with Type 2 protection at a downstream distribution panel.

 

Selection must still match the electrical system. Check operating voltage, phase arrangement, discharge-current rating, voltage protection level and earthing arrangement before choosing a surge protection device spd.

What to check before choosing a Type 2 SPD

Before selecting a surge protection device type 2, check:

• System voltage

• Single-phase or three-phase configuration

• Earthing arrangement

• Maximum continuous operating voltage (Uc)

• Voltage protection level (Up)

• Nominal discharge current (In)

• Maximum discharge current (Imax)

• Required protection modes

• Upstream protection

• Installation and connection requirements

These details help ensure the SPD matches the electrical system, rather than being selected only by its surge-current rating.

 

At Axis, we offer Type 1, Type 1+2 and Type 2 surge protection devices for different electrical applications, including single-phase and three-phase systems. Our team can help identify the appropriate SPD configuration based on system voltage, phase arrangement, protection requirements and installation conditions.

 

Need a surge protection device type 2 for your distribution system? Speak with Axis engineers about your system voltage, phase configuration and protection requirements to identify the suitable specification for your installation.

FAQs

Is a Type 2 SPD enough to protect a building from lightning?

Not always. A Type 2 SPD provides distribution-level protection, but installations with higher lightning exposure may also require Type 1 or Type 1+2 protection at the incoming supply. The complete protection arrangement should be based on the electrical system, lightning exposure and applicable design requirements.

What is the difference between Type 1 and Type 2 SPD?

Type 1 SPDs are used at the incoming supply to handle higher-energy surge exposure, including lightning-related surges. A surge protection device Type 2 is commonly installed at distribution boards to limit transient overvoltages reaching downstream circuits.

Can a Type 2 SPD protect equipment from lightning surges?

Yes. It can limit transient overvoltages linked to lightning-induced surges. A suitable protection arrangement depends on the installation and its exposure.

Where is a Type 2 SPD installed?

It is commonly installed at a distribution or subsidiary panel downstream of the main incoming protection.

What is an MOV in a Type 2 SPD?

MOV means Metal Oxide Varistor. Its resistance changes with voltage, allowing it to carry surge current during a transient event.

How do I select a Type 2 SPD?

Check system voltage, phase arrangement, maximum continuous operating voltage, discharge-current rating, voltage protection level and earthing arrangement.