Low voltage
The term Low voltage refers to voltages of less than 50 V (alternating voltage) or 120 V (direct voltage) respectively, according to standard DIN EN/IEC 60449. Plugs, connectors and sockets below 50 V do not require a protective conductor contact, and their clock positions are not standardised.
Due to the lack of a protective conductor contact in plugs and sockets with a rated current under 50 V, the connectors and receptacles are equipped with an earth nose and an auxilliary nose, the plugs have the corresponding grooves. The earth nose is always in clock position 6h. The position of the auxilliary nose depends on the rated voltage and frequency mentioned in table 208 and 209 from EN IEC 60309-2 (see below for more information). Contact bushings in sockets and connectors with a rated current below 50 V have to be arranged according to EN IEC 60309-2.
Arrangement of the minor keyway for various voltages and frequencies
Rated operating voltage V | Frequency Hz | Clockface position of keyway (major keyway = 6 o´clock) |
20 to 25 | 50 and 60 | no minor keyway |
40 to 50 | 50 and 60 | 12 |
20 to 25 and 40 to 50 | 100 to 200 300 400 > 400 to 500 DC | 4 2 3 11 10 |
25 | DC* | 8 * for portable electrical incubators – use with 12 V or 24 V direct-current voltage in ambulances or helicopters. |
Positions 1 and 9 are reserved for future standards. For design reasons, positions 5, 6 and 7 are not available for use.
If the rated operating voltage is indicated by a colour coding in addition to compulsory markings, such colour coding must be in accordance with EN IEC 60309-1:2023:
Rated operating voltage | Colour code | RAL* |
20 to 25 V | violet | 4001 |
40 to 50 V | white | 7035 |
* RAL determined by MENNEKES, as in EN 60309-1:1999 no specification is provided for.
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