Safety in the Classroom:
Connection Leads
The electrical contact pin on a safety connection lead (1) is insulated while the contact on a "normal" connection lead (2) is exposed. Contact hazardous voltages should therefore only be used with safety connection leads. So-called "non-hazardous contact voltage" may also, however, be used with normal connection leads according to DIN EN 61010-1 (VDE 0411). Non-hazardous contact voltage is defined as: 33 V~ and 70 V-.
In 2003, the Standing Conference of the Ministers of Education and Cultural Affairs set limits for students up to and including the 10th academic year in Section I-8.2 of its "Guidelines on Safety in the Classroom (GUV-SI 8070)": voltages up to a maximum of 25 V~ and 60 V= are considered to be safe to come into contact with. Students above the 10th academic year may also use hazardous voltages if the educational objective cannot be attained with safe voltages. In this case, however, the teacher must be present, check the wiring and point out any potential hazards.
Important! Many leading manufacturers of training and educational equipment and systems, among them Phywe, include switch boxes in their product range, which are not fitted with safety sockets and which bear an imprint indicating a maximum voltage of, for example, 250 V~. This means that the electrical components used are permitted for the specified voltage range. However, responsibility for electrical safety lies with the relevant specialist, in this case the Physics teacher, for example. It is therefore imperative that you take suitable precautions such as "Only carry out work on the circuit when the power is switched off", etc. For student experiments, however, the above-mentioned maximum voltages must be observed!
In our opinion the following therefore applies: you can continue to use the normal connection leads without any problems as long as the relevant permitted maximum voltage is not exceeded. Ultimately, though, the relevant regulations that are in force in your community or which have been stipulated by the senior school authority are the definitive standard.
