What are the UL SPD Type categories and what do they mean?

Type 1 SPDs (Listed) – Permanently connected, hard-wired SPDs intended for
installation between the secondary of the service transformer and the line side of the main
service equipment overcurrent protective device, as well as the load side of the main
service equipment (i.e. Type 1’s can be installed anywhere within the distribution
system). Type 1 SPDs include watt-hour meter socket enclosure type SPDs. Being on the
line side of the service disconnect where there are no overcurrent protective devices to
protect an SPD, Type 1 SPDs must be listed without the use of an external overcurrent
protective device. The Nominal Discharge Current Rating for Type 1 SPDs is either
10kA or 20kA.

Type 2 SPDs (Listed) – Permanently connected, hard-wired SPDs intended for
installation on the load side of the main service equipment overcurrent protective device.
These SPDs may also be installed at the main service equipment, but must be installed on
the load side of the main service overcurrent protective device. Type 2 SPDs may or may
not require an overcurrent protection device per their NRTL listing. If a specific
overcurrent protection is required, the SPD’s NRTL listing file and labeling/instructions
are required to note the size and type of overcurrent protective device. Note: In some
cases the overcurrent protective device used can impact the nominal discharge rating of
the SPD. For example, the SPD may have a 10 kA nominal discharge current rating
when protected by a 30 Amp circuit breaker and a 20 kA nominal discharge current
rating when protected by a different but specific make and model of overcurrent
protection device. The Nominal Discharge Current Rating for Type 2 SPDs is 3 kA, 5
kA, 10 kA, or 20 kA.

 

Type 3 SPDs (Listed) – These SPDs are called, ‘Point of Utilization SPDs’, which are to
be installed at a minimum conductor length of 10 meter (30 feet) from the electrical
service panel unless they are evaluated at Type 2 SPDs (that is, they receive a Nominal
Discharge Current Rating of 3 kA minimum). Typically, these are cord-connected surge
strips, direct plug-in SPDs, or receptacle-type SPDs installed at the utilization equipment
being protected (i.e. computers, copy machines, etc.).

 

Type 1, 2, 3 Component Assembly SPDs (Component Recognized) – These SPDs are
intended to be factory installed into electrical distribution equipment or end-use
equipment. These are Recognized Component SPDs evaluated for use in Type 1, 2 or 3
SPD applications. Such component SPDs must pass all the same electrical safety failure
tests as listed Type 1, 2 or 3 SPDs. While these SPDs are 100% compliant from a safety
failure testing point of view, these Type 1, 2 and 3 component assembly SPDs have
conditions of acceptability such as exposed terminals or other mechanical construction
that requires them to be installed or housed within a listed assembly to provide protection
from exposure to live parts or other requirements. These Type 1, 2 or 3 Recognized
Component SPDs should not be confused with ANSI/UL 1449-2006 Type 4 Component
Assemblies and Type 5 discrete SPD components that require additional components
(possibly safety disconnectors), design and testing in order to be used as a complete surge
protective device.

 

Type 4 Component Assembly SPD (Component Recognized) –– These component
assemblies consist of one or more Type 5 SPD components together with a disconnector
(integral or external) or a means of complying with the limited current tests in UL 1449,
Section 39.4. These are incomplete SPD assemblies, which typically are installed in
listed end-use products as long as all conditions of acceptability are met. These Type 4
component assemblies are incomplete as an SPD, require further evaluation and are not
permitted to be installed in the field as a stand-alone SPD. Often, these devices require
additional overcurrent protection.

Type 5 SPD (Component Recognized) – Discrete component surge protection devices,
such as MOVs that may be mounted on a printed wiring board, connected by its leads or
provided within an enclosure with mounting means and wiring terminations. These Type
5 SPD components are incomplete as an SPD, require further evaluation and are not
permitted to be installed in the field as a stand-alone SPD. Type 5 SPDs are generally the
components used in the design and construction of complete SPDs or other SPD
assemblies.

2017-10-31T16:58:48+00:00