The biggest risk with lighting, was made very clear. Death. It's obvious really that when working with anything electrical there's the risk of electrocution and death. There's also a big worry with people getting burnt. To overcome this there are various safety precautions to take:

• A health and safety check should be performed before every shoot
• Always wear gloves when handling lights to avoid burns
• Always check the gloves for holes. If there are any then throw the gloves away
• Perform a visual check of all equipment (wires should be checked for holes etc)
• Don't leave wires wound up as they can generate heat
• Wires should be stuck down or covered with rubber mats to avoid trip hazards
• Don't touch 'barn doors' when light is on without wearing gloves
• All lights should have a 'scrim' and circuit breaker
• The light wire should hang from the rear of the light
• Wire should hang to the floor, rather than being stretched to plug socket
• Lights should be left to cool for 5+ minutes after being used

The health and safety slide show can be found on the VLP here.