These practical activities are great to get your class involved in home safety. Let them create role plays and you will be surprised at how creative they can be, all whilst working together. I love the idea of a field trip, but if it's just not practical you could consider having a guest speaker come and talk to your class instead.
The Child Accident Prevention Trust has put together these few lesson plans regarding safety in the home. They can be adapted for various ages and abilities and even include homework and extension activities. Follow the plans exactly, or use some of the activities in your own lessons.
This site covers an extensive range of home safety areas so you can pick and choose depending on the needs of your class. I really like 'when it's just you after school' as many students are probably home alone at times, often with other siblings too.