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What is a plug-on current transformer with UL approval (CTB)?
The CTB is a plug-on current transformer with pluggable spring-loaded terminal (Cage Clamp) for tool-free secondary connection and a UL approval that also makes it suitable for systems with US-American or internationally standardized certification requirements.
When a CTB is the right choice
The CTB is suitable wherever a UL certification is required in addition to the pure measuring function – for example in export projects or systems with international acceptance requirements. Without this requirement, the classic plug-on current transformer (ASK) is usually the more obvious choice.
Technical features
- Primary current 50 A to 2.500 A
- Secondary current 1 A and 5 A
- Accuracy classes 1 and 3
- 20 % continuous overload possible
- UL-certified, plug-in terminal (Cage Clamp)
Mounting and safety
The secondary circuit of a current transformer must never be operated open during operation – before disconnecting measuring devices in the secondary circuit, it must be short-circuited.
The unbreakable, self-extinguishing polycarbonate housing guarantees maximum safety and durability
Versions at a glance
The available CTB variants can be found in the product list above. If you have any questions about the right selection, please use our contact form or call us.
Frequently asked questions
Der CTB hat dieselbe Aufsteck-Montage wie der ASK, zusätzlich aber eine steckbare Federzugklemme (Cage Clamp) für den werkzeuglosen Sekundäranschluss sowie eine UL-Zulassung für Anlagen mit US-amerikanischen oder international genormten Zertifizierungsanforderungen.
Immer dann, wenn die Anlage nach US-amerikanischen oder international genormten Zertifizierungsanforderungen abgenommen wird, etwa bei Exportprojekten. Ohne diese Anforderung ist der klassische ASK meist die naheliegendere und wirtschaftlichere Wahl.