Electrical Safety Mark Gough Electrical Inspector Northern Specialist Group

Topics Covered Duties of Inspector Generation Distribution Case Studies

Duties LEGAL prevent danger to your self and others affected by your undertaking. Recent case inspection company fined £ and possible manslaughter charge Moral to ensure safety Fairground Operators and members of public Economic Comprehensive inspection and testing is a skilled job and takes time. FFI, loss business you and operator, PN’s IN’s Fines, court costs etc all uninsurable

Fairground Generation Generator or transformer Note 5 conductors Essential

230 V 50 Hz If you touch the ride with fault and adjacent metalwork what will happen Oooerr! Generators with 4 conductors

230 V 50 Hz Current flows from the supply, through the fault, through her and back to the supply via earth. Aaagghhh! Protection against Indirect Contact

230 V 50 Hz What happens when I introduce the same type of fault as before? Protective Conductor Fuse If you add an earth conductor 5 wire system

230 V 50 Hz Protective Conductor Fuse ‘Earth Fault Loop Impedance’ It’s determined by the voltage and the ‘Earth Fault Loop Impedance’ – a very important system parameter. If it’s too high not enough current will flow to blow the fuse quickly enough to prevent danger. Protection against Indirect Contact

230 V 50 Hz Fuse Not Again!! Here the fairground owner has joined the neutral and earth. What Would happen? Protection against Indirect Contact

230 V 50 Hz Fuse Oh for Goodness Sake!! Here the return is damaged The exposed metal work of the ride could become live. If the return is damaged Protection against Indirect Contact

230 V 50 Hz Protective Conductor Fuse Now let’s introduce a ‘bonding’ conductor that connects the exposed metalwork together. Protection against Indirect Contact

230 V 50 Hz Protective Conductor Fuse Protection against Indirect Contact This is clever stuff. I wish I could be an Electrical Engineer. We have here the concept of Earthed Equipotential and Automatic Disconnection of Supply (EEBADS) – the fundamental safety system in the UK for protection against indirect contact electric shock.

At Generators Check 5 conductors (no more or less) Do an earth loop impedance test or earth to neutral continuity Fused correctly working 100mA RCD? Earth spike? Preferable not as important as earth neutral continuity test

What can be done including 30mA RCD

Distribution 30mA RCD sockets and lighting Suitable plugs Short runs Damaged Cables Overloaded Circuits

Recap Generators 5 core AND earth neutral continuity (ELI test) 100mA RCD time delayed Final circuits 30mA RCD BSEN plugs / sockets Encourage use of plug in testers

Competence Costs BUT Incompetence Costs More