Precautions against burn injuries

Some electrical bums occur without the victim suffering an electric shock and merit, therefore, separate preventive measures. These are described in this section. [Pg.46]

Many burn injuries are caused by flame arcs emitted with explosive violence when short circuits occur in apparatus where the fault levels are high. The short circuits often take place during live working when conductive parts such as bolts, nuts and washers are accidentally dropped and bridge between a phase conductor and earthed metalwork, or between phases. Another common cause is the use of uninsulated or insufficiently insulated tools which can bridge conductors in the same way. [Pg.46]

Bare instrument probes can also cause short circuits, arcing and injury to the user. Only the contact points should be bare, with a maximum length of exposed metal of 4 mm, and the rest of the probe insulated. For some applications, probes with retractable contacts can be used with advantage. Advice on the safety standards for electrical instruments for use by electricians is published in the HSE s Guidance Note GS38. [Pg.47]

A common cause of RF contact burns is from the metal electrode jigs of dielectric heating and plastics welding apparatus, operating at radio frequencies. Unless the output is pulsed there is unlikely to be a shock risk, but an accidental hand contact, for example, will draw out an arc when the hand is removed and a high frequency burn will result. The burning is a function of the arc energy, and for low power apparatus only a minor burn is likely. More powerful equipment, above about 1 kW, can inflict more serious burns. [Pg.47]

Where a number of electrodes are clamped manually to the work piece, as in glue curing of joints in wood fabrications, a guard or fence can be used, interlocked with the electronic control gear to keep the operator away from the work piece when the electrodes are energised. [Pg.47]

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