Camlock (electrical)

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Cam-locks
Cam-lock prior to use
Cam-lock prior to use
Cam-lock in use
Cam-lock in use

A camlock, (named after the Cam-lok connector made by the Crouse-Hinds Company, a division of Cooper Industries) or 'cam' for short is often used in temporary electrical power production and distribution. Interchangeable connectors are made by Leviton, Hubbell, and other companies. The most common form is the 16 series, rated at 400 amperes with 105 °C terminations. Also in common use is the 15 series (mini-cam), rated at 150 amperes.

They are generally used where more than 50 A is required or 3 phase connections are needed, and to connect large generators or building disconnects to distribution panels or lighting dimmer racks. They are usually found only in professional environments.

The colors correspond to the different functions of the terminals. Extra caution should be used to verify correct phase in relation to color coordination with foreign companies and equipment in traveling productions. The common American colors are:

120/208 volt wye and 240 volt delta
Green Equipment Grounding Conductor
White Neutral (Grounded conductor)
Black Ø 1
Red Ø 2
Blue Ø 3
277/480 volt wye or 480 volt delta
Green Equipment Grounding Conductor
White Neutral (Grounded conductor, if used)
Brown Ø 1
Orange Ø 2
Yellow Ø 3

It is very often assumed that these colors are dictated by the National Electric Code (NEC), however they are not. The NEC only requires that green must only be used for the Equipment Grounding Conductor (NEC Article 250.119) and only white or grey for the Neutral (groundED) conductor (NEC Article 200.6). These colors may not be used for any other purpose, nor may their purpose use a different color. No other colors are specified by the NEC for general power distribution.

The UK system uses the following colour codes: (as the use of Camlocks has been declining, it is very unlikely to find any matching the new colour codes)


UK Camlock Colour Codes
Colour (Old) Colour (New) Use
Green Green Earth
Black Blue Neutral
Red Brown L1
Yellow Black L2
Blue Grey L3

Extra care should be taken when connecting together systems using old and new colour codes, especially as black was originally used to indicate neutral and is now a phase colour, and blue which used to denote a phase is used to denote neutral.


See also[edit]