Screw terminals are commonly used to connect a chassis ground, such as on a record player or surge protector. Most public address systems in buildings also use them for speakers, and sometimes for other outputs and inputs. Alarm systems and building sensor and control systems have traditionally used large numbers of screw terminations.
Grounding screws are often color-coded green and, when used on consumer electronics, often have a washer with gripping "teeth".
The wire is wrapped directly under the head of a screw, held by a metal plate forced against the wire by a screw, or may be held by what is, in effect, a set screw in the side of a metal tube. The wire may be directly stripped of insulation and inserted under the head of a screw or into the terminal. Otherwise, it may be either inserted first into a ferrule, which is then inserted into the terminal, or else attached to a connecting lug. which is then fixed under the screw head.
Depending on the design, a flat-blade screwdriver, a cross-blade screwdriver, hex key, Torx key, or other tool may be required to properly tighten the connection for reliable operation.
Material
| Insulation material |
PA66 |
| Flame retardant rating |
UL94V-0 |
| Conductor material |
Copper alloy |
| Plating of conductor surface |
Sn plated |
Electrical
| Standed |
UL IEC |
| Rated voltage |
300V 250/320/630V |
| Rated current |
15A 12A |
Mechanical
| Temp.range |
-40ºC-+105ºC |
| Stripping length |
7-8mm |
Multiple screw terminals can be arranged in the form of a barrier strip (as illustrated at the top right), with a number of short metal strips separated by a raised insulated "barrier" on an insulating "block" - each strip having a pair of screws with each screw connecting to a separate conductor, one at each end of the strip. These are known as connector strips or chocolate blocks ("choc blocks") in the UK. This nick-name arises from the first such connectors made in the UK by GEC, Witton in the 1950s. Moulded in brown plastic they were said to resemble a small bar of chocolate.
A similar arrangement is common with paired screw terminals, where metal tubes are loosely encased in an insulating block with a set screw at each end of each tube to hold and thus connect a conductor. These are often used to connect light fixtures and are shown at the right.
Alternatively, terminals can also be arranged as a terminal strip or terminal block, with several screws along (typically) two long strips. This creates a bus bar for power distribution, and so may also include a master input connector, usually binding posts or banana connectors.
COMPANY PROFILE
☆ Privately held company, established in 1999
☆ Sales volume over 16 Million USD since 2017
☆ OEM & ODM company, with employees more than 250 persons, 7260 square-meters in size
☆ Service for economical solutions and innovative wire harnesses design & manufacturing
☆IATF16949 (2016) & ISO 9001 (2015), and UL certified supplier with wiring No. E468011 & cable No. E479323
CERTIFICATION
Q&A
1. Q: Can you help to design?
A: Yes, we are an ODM / OEM company, beyond we have been specializing in wire harness & Cable assembly since 1999.
2. Q: When will you start to help design?
A: We sketch simple solution for initial discussion, after quotation and order placed then start to drawing and double confirm with client for the design.
3. Q: What if quality issues occur when customer discover?
A: Our quality and engineer team will positively respond for the quality issues with 72 hours, as we are intend to make long-stand strategy with customer and the value is to provide better service.
4. Q: Do you have any standard products to cut down customers lead time for prototype and tooling cost?
A: Yes, there are over 1000 sets of molds and some of them can be used for customer directly. Moreover, Edgar is specialized in wire harness over 20
years with 5000+ products
CONTACT US
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