Electrical wiring advice - Static caravan

by David Causton
(Perth)

I have fitted a heat trace cable to the cold water main under the caravan. I have connected it to a junction box with a 1mm twin and earth. From that junction box to a thermostat. From thermostat into the bedroom wardrobe consumer.

There is a gap for me to put a 6 amp breaker in there. Do I have to put a link wire from the bottom of my 6 amp breaker to the live.