Laboratory Safety

The first thing you should be concerned about in the lab is the safety of yourself and your fellow students. There are a number of potentially serious hazards in this lab, but if you are aware of the dangers and use sensible precautions, you will be quite safe.

Electrical hazards

Electrocution is by far the most serious hazard. You will be working continually with electrical equipment, which sometimes uses high voltages. You should always be aware when you are working near exposed wires, and whenever you are changing high voltage electrical connections always double check that the power is turned off, and any capacitors, either inside the power supply or outside, are discharged. One of the primary dangers of working with high voltages is that you do not have to actually touch a wire to be shocked‑ the current can arc to your body even if you are a few mm away. A good standard practice when working with exposed high voltage is to always keep one hand in your pocket to avoid the possibility of a current entering your body through one hand and leaving through the other, because it is closest to ground. The reason this is particularly bad is that the current will pass through your heart and start it fibrillating. Most accidental electrocutions are due to fibrillation. For this reason the most lethal voltage levels are around 400-500 V, since this is most likely to lead to currents which cause fibrillation. Higher voltages (for example, 2000 V), while still dangerous, tend to cause the heart muscle to simply spasm, but beating will usually resume if the voltage is removed quickly. High voltage, high current sparks frequently cause very deep burns which take a long time to heal. The 120 V line power is relatively safe, but still can provide painful shocks and can be quite dangerous if your body is a relatively low resistance path, for example if your hands are wet when you touch the wire. Voltages below 50 V usually involve little danger.
Click here for additional notes on electrical safety.