Does anyone know if there are new sybols for themal protection of magnetic ballasts out? class "P" ballast used to be a "P" inside a triangle. i am running across ballasts with a "P" in a circle with a "T" is this a new symbol for thermal protection?
dwolf351
This may help Welcome to ET...:thumbup:
http://www.robertsonww.com/products/info/1004.pdf
Class P Standards
The National Electrical Code (NEC) requires
indoor fluorescent fixtures to incorporate ballast
thermal protection. Underwriters Laboratories
has implemented this requirement by developing a
standard encompassing ballast protection. Ballasts
meeting this standard for protection are designed
class “P”.
Such a ballast is protected internally by a device
which will disconnect the ballast from the power
line in the event that the temperature limit is
exceeded. This protection guards against excessive
temperatures which may be caused by abnormal
voltage
or internal faults that may occur at the end of
ballast life. It does not affect normal ballast
operating temperatures.
All Class “P” magnetic ballasts have thermal
protective devices. Electronic ballasts are not
required to have an actual thermal switch for
Class “P” listing. Class “P” listing denotes that the
case temperature will not exceed a specified value in
the event of a component failure. Many electronic
ballasts comply with Class “P” requirements
by means of “Inherent Thermal Protection”
incorporated in the circuitry. Such ballasts are
marked accordingly. These ballasts are fully tested
to all Class “P” requirements, just as those with
thermal protection devices. They comply by virtue
of the fact that the circuitry will shut down and
inherently stop producing heat, thus resulting in
no temperature increase in the event of internal
component failures or application abnormalities.
Class “P” requirements are specified by UL,
not CBM. A Class “P” ballast may be a CBM
ballast, but only if it meets the ANSI performance
specifications. The designation Class “P” alone
does not signify CBM Certification.
http://www.robertsonww.com/products/info/1004.pdf
Class P Standards
The National Electrical Code (NEC) requires
indoor fluorescent fixtures to incorporate ballast
thermal protection. Underwriters Laboratories
has implemented this requirement by developing a
standard encompassing ballast protection. Ballasts
meeting this standard for protection are designed
class “P”.
Such a ballast is protected internally by a device
which will disconnect the ballast from the power
line in the event that the temperature limit is
exceeded. This protection guards against excessive
temperatures which may be caused by abnormal
voltage
or internal faults that may occur at the end of
ballast life. It does not affect normal ballast
operating temperatures.
All Class “P” magnetic ballasts have thermal
protective devices. Electronic ballasts are not
required to have an actual thermal switch for
Class “P” listing. Class “P” listing denotes that the
case temperature will not exceed a specified value in
the event of a component failure. Many electronic
ballasts comply with Class “P” requirements
by means of “Inherent Thermal Protection”
incorporated in the circuitry. Such ballasts are
marked accordingly. These ballasts are fully tested
to all Class “P” requirements, just as those with
thermal protection devices. They comply by virtue
of the fact that the circuitry will shut down and
inherently stop producing heat, thus resulting in
no temperature increase in the event of internal
component failures or application abnormalities.
Class “P” requirements are specified by UL,
not CBM. A Class “P” ballast may be a CBM
ballast, but only if it meets the ANSI performance
specifications. The designation Class “P” alone
does not signify CBM Certification.
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